Inorganic Chemistry of the Main-Group Elements

A Specialist Periodical Report

Inorganic Chemistry of t h e Main-group Elements Volume 3

A Review of the Literature Published between September 1973 and September 1974 Senior Reporter C. C. Addison

Reporters

M. G. Barker G. Davidson M. F. A. Dove P. G. Harrison P. Hubberstey A. Morris R. J. Pulham D. B. Sowerby

All of: Department of Chemistry, University of Nottingham @ Copyright 1976

The Chemical Society Burlington House, London W I V OBN

ISBN 0 85186 772 3 ISSN 0305-697X Library of Congress Catalog Card No 72-95098

Filmset in Northern Ireland at The Universities Press, Belfast Printed by photolithography, and bound in Great Britain at The Pitman Press, Bath

Preface The general layout of Volume 3 follows closely that which has been successful in the first two volumes, so that discussion of the elements takes place in eight chapters. Each chapter is concerned with one of the Main Groups of the Periodic Table, and the volume is again written by members of the Department of Chemistry in the University of Nottingham. Volume 2 was larger than Volume 1, and there are so many current topics of interest that it would have been easy, on scientific grounds alone, to continue this expansion. However, other factors, largely economic, now arise which require that future volumes should be limited in size, and in consequence Volume 3 is appreciably smaller than Volume 2. This has been achieved to a small extent by treating groups of references together in tables and lists, but to a greater extent by considering carefully the amount of physical data which is appropriate to this particular Report, and limiting such data to the minimum necessary to illustrate the property under discussion. More important still, the authors are no longer able to claim that their articles are comprehensive. Instead, we have attempted to include all themes of current interest, and hope that it will be possible to deal with items which are at present chemically isolated, by back reference in a future volume. The authors have also discussed whether there are any general trends which have become apparent. Although there are variations from Group to Group, there is an overall impression that the quantity of worthwhile published research in the area of Main-group chemistry has diminished somewhat during the past year. C . C . Addison.

...

111

Con tents Chapter 1

Elements of Group I

1

By R. J. Pulham

1

Introduction

1

2

TheAlkaliMetals

1

3

Alloys and Intermetallic Compounds

7

4

Solvation of Alkali-metal Ions Aqueous Solvation Non-aqueous Solvation

9 9 13

5

Compounds containing Organic Molecules or Complex Ions

17

6

Alkali-metal Oxides

35

7

Alkali-metal Halides

38

8

Lithium Compounds

42

9

Sodium Compounds

46

10

Potassium Compounds

51

11

Rubidium Compounds

53

12

Caesium Compounds

54

13

Molten Salts Nitrates Halides

55 56 57

Elements of Group II

64

Chapter 2

By R. J. Pulharn

1

Beryllium

64

2

Magnesium

70

3

Calcium

79 V

Contents

vi

4

Strontium

86

5

Barium

89

Chapter 3 1

2

3

4

Elements of Group Ill By G. Davidson

95

Boron General Boranes Borane Anions and Metallo-derivatives Carbaboranes Metallo-carbaboranes Compounds containing B-C Bonds Aminoboranes and Other Compounds containing B-N Bonds Compounds containing B-P Bonds Compounds containing B-0 Bonds Compounds containing B-S or B-Se Bonds Boron Halides Boron-containing Heterocycles Metal Borides

95 95 96 100 106 116 129

Aluminium General Aluminium Hydrides Compounds containing A1-C Bonds Compounds containing A1-N or Al-P Bonds AI-S, or Compounds containing A1-0, AI-Se Bonds Aluminium Halides

131 136 138 143 145 150 158

159 159 160 161 163 165 172

Gallium General Gallium Hydrides Compounds containing Ga-C Bonds Compounds containing Ga-N, Ga-P, or Ga-As Bonds Compounds containing Ga-0 or Ga-S Bonds Gallium Halides Other Gallium Compounds

175 175 175 176

Indium General Compounds containing Bonds between In and Group VI Atoms

181

176 177 179 180

181 181

vii

Contents Indium Halides Other Indium Compounds Thallium

5

Thallium(n1) Compounds Thallium(1) Compounds Other Thallium Compounds

Elements of Group IV

Chapter 4 1

2

By P. G. Harrison a n d P. Hubberstey Carbon Carbon Allotropes Structural Studies Chemical Studies Graphite Intercalation Compounds Alkali Metals Halogens, Halides, and Oxides Methane and its Substituted Derivatives Theoretical Studies Structural Studies Spectroscopic Studies Chemical Studies Formaldehyde and its Substituted Derivatives Formaldehyde, Carbonyl Halides, etc. Formic Acid and Formates Derivatives of Group VI Elements Oxides, Sulphides, and Related Species Carbonates, Thiocarbonates, and Related Anions Derivatives of Group V Elements Cyanogen, Cyanides, Cyanates, and Related Species Silicon Germanium, Tin, and Lead Hydrides of Silicon, Germanium, and Tin Silicon Solid-state Chemistry Silicon Dioxide Silicates Germanium(rv), Tin(rv), and Leaduv) Oxides, and Related Germanates and Stannates Molecular Silicon(rv)-, Germanium(1v)-, Tin(Iv)-, and Lead(rv)-Oxygen Compounds Oxides Alkoxides and Related Derivatives Carboxylates and Oxy-acid Derivatives

183 183 184 184 185 188

190 190 191 193 195 197 198 199 201 20 1 202 205 207 212 212 215 215 215 220 223 223 226

226 229 229 232 240 24 1 241 243 249

...

Contents

v111

Halides of Silicon, Germanium, Tin, and Lead Pseudohalide Derivatives of Silicon, Germanium, Tin, and Lead Sulphur and Selenium Derivatives of Silicon, Germanium, Tin, and Lead Nitrogen and Phosphorus Derivatives of Silicon, Germanium, and Tin Derivatives of Silicon, Germanium, Tin, and Lead containing Bonds to Main-group Metals Derivatives of Silicon, Germanium, Tin, and Lead containing Bonds to Transition Metals Bivalent Derivatives of Silicon, Germanium, Tin, and Lead Unstable Silylenes and Germylenes Halogen Derivatives Oxygen Derivatives Sulphur Derivatives Nitrogen Derivatives Interactions of Bivalent Germanium and Tin Compounds with Transition-metal Derivatives

3

Chapter 5

Intermetallic Phases Binary Systems Ternary Systems

Elements of Group V

25 1

258 259 264 275 280 294 294 295 298 303 305

305 309 309 311

314

By A. Morris and D. €3. Sowerby

1

Nitrogen Elementary Nitrogen Bonds to Hydrogen N H and NH2 Species NH, NH: NH,OH and Derivatives N2H2and its Derivatives N,H, and Derivatives Bonds to Nitrogen hides Other Species Bonds to Oxygen N*O NO NOz-NzO,

314 3 14

316 3 16 316 318 318 320 321 323 323 325 325 326 326 327

ix

Contents

Nitric Acid and Nitrates Fremy’s Salt and Derivatives Nitrogen Oxides and Atmospheric Chemistry Bonds to Fluorine Bonds to Halogen

2

3

Phosphorus Phosphides Hydrides Compounds containing P-P bonds Bonds to Boron Bonds to Carbon Phosphorus(rr1)Compounds Phosphorus(v) Compounds Bonds to Silicon Bonds to Fluorine Phosphorus(rr1)Compounds Phosphorus(v) Compounds Oxyphosphorus(v)Compounds Bonds to Chlorine Phosphorus(II1)Compounds Phosphorus(v) Compounds Oxyphosphorus(v)Compounds Bonds to Bromine or Iodine Bonds to Nitrogen Phosphorus(Ir1)Compounds Phosphorus(v) Compounds Compounds containing P-N-P Bonds Compounds containing PnNn Rings Compounds containing Heteroatom Ring Systems Bonds to Oxygen Compounds of Lower Oxidation State Phosphorus(v) Compounds Monophosphates Apatites Diphosphates Cyclic Metaphosphates Polyphosphates Phase Studies Powder Diffraction Data Bonds to Sulphur or Selenium Arsenic Arsenic and Arsenides Bonds to Carbon

329 333 333 335 336 337 337 337 338 340 341 34 1 343 344 344 344 347 350 35 1 35 1 352 354 357 357 357 360 3 62 363 370 371 37 1 372 375 378 378 379 379 3 80 38 1 381 3 84 384 385

Contents

X

Halogens Nitrogen Oxygen Sulphur or Selenium

386 388 389 392

Antimony Antimony and Antimonides Bonds to Carbon or Nitrogen Bonds to Halogens Antimony(n1) Compounds Antimony(v) Compounds Bonds to Oxygen Bonds to Sulphur, Selenium, or Tellurium Bismuth

393 393 393 395 395 397 399 400

Bonds Bonds Bonds Bonds

4

5

Chapter 6

to to to to

Elements of Group VI

40 1

403

By M. G. Barker

1

2

403 Oxygen The Element 403 405 Ozone 406 Oxygen Fluorides Hydrogen Peroxide 406 407 Other Hydrogen-Oxygen Compounds Water 408 Sulphur 409 409 The Element Sulphur-Halogen Compounds 412 41 5 Sulphur-Oxygen-Halogen Compounds 418 Sulphur-Nitrogen Compounds 418 Linear Compounds 423 Cyclic Sulphur-Nitrogen Compounds Cyclic Compounds containing Sulphur, Ni427 trogen, and other Elements in the Ring 430 Other Sulphur-containing Ring Compounds 43 1 Sulphur-Oxygen Compounds 43 1 Binary Oxides 433 Sulphates Fluoro- and Chloro-sulphates 436 Other Oxyanions of Sulphur 437 439 Sulphuric Acid and Related Compounds Sulphides 440 Hydrogen Sulphide 440 Metal Sulphides 44 1 Group IV Metal Sulphides 443

xi

Contents

3

4

Group V Metal Sulphides Other Metal Sulphides Other Sulphur-containing Compounds

446 447 448

Selenium The Element Selenium-Oxygen-Halogen Compounds Selenium-Oxygen Compounds Selenates and Selenites Acids of Selenium Selenides Other Compounds of Selenium Tellurium

45 1

The Element Tellurium-Halogen Compounds Compounds containing Tellurium-Oxygen Bonds Tellurides

Chapter 7 The Halogens and Hydrogen

45 1 454 45 5 456 459 459 46 1 462 462 463 467 467

469

By M. f. A. Dove

1

2

Chapter 8

Halogens Elements Halides Interhalogens and Related Species Oxide Halides Oxides and Oxyanions Hydrogen Halides

469 469 473 476 48 1 483 487

Hydrogen Protonic Acid Media Hydrogen-bonding Miscellaneous

489

The Noble Gases

495

489 490 494

By M. f. A. Dove

The Elements

495

Krypton, Xenon, and Radon@)

496

Xenon(rv)

498

Xenon(w)

499 502

Author Index

503

1 Elements of Group I BY R. J. PULHAM

1 Introduction In this chapter individual references which are inter-related are grouped together to make assection and, therefore, reference to several alkali metals may feature in a single section. Each reference, however, appears oncG only ill not be within this chapter so that, if described in one section, it w duplicated in any other. Single references to topics are presented systematically in the section on the appropriate metal. The elements of Groups I and I1 are so closely linked in some instances that a section describing them jointly is presented to avoid duplication in Chapter 2. Such a case is the section on ‘Molten Salts’, which covers the chemistry of the molten salts of both Groups I and I1 but is presented only in this chapter.

2 The Alkali Metals The electron afFinities/eV (&0.05),determined from the threshold energies of the photo-detachment cross-sections of the atomic negative ions, are 0.61, 0.53,0.50,0.48,and 0.47 for Li, Na, K, Rb, and Cs, respectively. The values for Rb and Cs were obtained by extrapolating the cross-section below 0.5 eV. All values for the alkali metals are abstracted from a set covering the elements of the short periods.’ The reaction cross-sections of alkali-metal atoms with Br, have been obtained by direct measurements of alkali-metal atom decay rates. The alkali-metal atoms were produced in the presence of a known amount of Br, by photodissociating the bromide of the particular alkali-metal atom with a short pulse of U.V. light. As the atoms reacted with Br, their decay rate was determined from the transmission of alkali-metalatom resonance light through the vapour. The reaction cross-sections/& as computed from the decay rates are Na, 116; K, 151; Rb, 197, and caesium, 204, and are accurate to ca. 15%.’ Theory and experimental practice in the field of soft X-ray emission from metallic solids have been briefly reviewed, D. Feldmann, R. Rackwitz, E. Heinicke, and H. J. Kaiser, Phys. Letters (A), 1973,45,404. J. Maya and P. Davidovits, J. Chem. Phys., 1973, 59, 3143.

1

2

Inorganic Chemistry of the Main -group Elements

and measurements on a number of systems including Li, Na, and Mg, are critically evaluated. Comparison is made with the results of other techniques and theory to establish the pertinence of soft X-ray measurements and to indicate specific guidelines for further enhancing their value. An exhaustive annoted index of measured spectra is also provided.' X-Ray photoelectron spectra of Li and Na obtained in ultrahigh vacuum show rich plasmon structures on all peaks. Both the photoemission and Auger peaks showed large extra-atomic relaxation energies. The sodium valence band showed an approximately E '', behaviour, as expected for a nearly free-electron metal, but it has some a n ~ m a l y Further .~ X-ray photoemission spectra of valence and core electrons in Na and NaOH have been measured from clean and oxidized Na films. Clean metal surfaces were prepared by sequential evaporation to give films contaminated with only half a monolayer even after several hours. From these films an analysis of lineshapes of core-electron spectra revealed evidence for the effects of electron-hole interactions. The valence band of Na was determined as free-electron-like again, with an occupied bandwidth in hgreement with theory. Accurate binding energies/eV for the core Na, 2p, 2s, and 1s electrons are 30.58k0.08, 63.57*0.07, and 1071.76 0.07, respectively. By comparison with core-level spacings in the free ion and crystal, the measured 2s and 1s electron binding energies in the metal were anomalously large. The valence band of NaOH resembled that of H,O(g) after shifting the vapour spectrum to lower binding energies. Evidence was found for weakly chemisorbed N, on the NaOH surface.' The work function of rubidium films deposited on quartz substrates at lo-'" Torr has been determined photoelectrically as 2.261 *O.OlS eV at 140 K. On warming to 1SO-200 K, an irreversible decrease occurred in photoelectric yield.6 Semi-empirical potential-energy surfaces have been calculated for the alkali-metal atom-dimer exchange reactions of Li and Na. The surfaces exhibit a potential well at small internuclear distances which extends into the entrance and exit valleys without an energy barrier. The alkali-metal triatomic complex is deemed most stable in the linear or near-linear configuration but remains stable, however, over all bent configurations. In the mixed complex, the configuration with the lighter Li in the central position is the more stable, i.e. NaLiLi is more stable than LiNaLi, and NaLiNa is more stable than NaNaLi.' It is considered that the diatomic ox molecular orbitals rather than the p atomic orbitals can probably function as . the metallic orbitals in the simplest account of the Pauling valence-bond theory of electron conduction in alkali metals.' High-temperature vapour pressures and critical points have been determined for potassium and

*

*

A . J. McAlister, R. C. Dobbyn, J. R. Cuthill, and M. L. Williams, Report 1974, NBS-SP-369. S. P. Kowalczyk, L. Ley, F. R. McFreely, R. A. Pollak, and D. A . Shirley, Phys. Reu. ( B ) , 1973, 8, 3583. P. H. Citrin, Phys. Rev. (B),1973, 8, 5545. T. W. Hall and C. H. B. Mee, Phys. Status Solidi ( A ) , 1974, 21, 109. J. C . Whitehead and R. Grice, Mol. Phys., 1973, 26, 267. R. D. Harcourt, J. Phys. (B), 1974, 7, LA-L45.

Elements of Group I 3 rubidium. These lead to values of the enthalpy of vaporization of the K and Rb monomers at 0 K of 23.816’ and 20.3 kcal mol-l,lo respectively. The critical density of Rb is 0.347 f 0.002 g ~ m - ~ . ” The ignition and combustion of sodium has been reviewed’’ and the ignition temperatures of both sodium and potassium have been experimentally determined under conditions of slow heating in air, dropping the metal into hot air, and heating the metal under argon followed by exposure to air or oxygen.” In a theoretical treatment for solutions of non-metal X in a liquid alloy A-B, a parabolic dependence of solvation energy on the number of atoms A and B in the solvation shell of atoms X has been introduced in place of the usual linear relationship. Calculations of the activity coefficient of oxygen as a function of alloy composition using this modification agree with available experimental data. Although the concept is developed solely for oxygen (and other non-metals) in transition-metal alloys, it appears generally applicable to solutions of non-metals in liquid alkali metals a l ~ 0 . A I ~previous model for solutions of non-metals in liquid alkali metals has been extended. Electronegative non-metals are considered as anions in the liquid and solvated by cations. A method is given for calculating the Coulomb interaction between screened potentials round cations and anions in the free-electron gas of the metal using the Fourier convolution theorem.” The solubilities of the salts NaBr and NaI in liquid sodium have been determined from 150 to 450°C. The labelled halides (Na32Brand Na1311), as dried-down deposits on steel surfaces, were equilibrated with both static and flowing liquid sodium, which was subsequently analysed for halogen by gamma spectrometry. The solubilities, S/p.p.m. by weight, of NaBr and NaI respectively are given by the equations: log S = 9.00 - (5100 K/T) and

log S = 8.72 - (4650K/T)

The slopes of these lines provide partial molar enthalpies of solution of 97.5 f4.7 and 89.2 f2.6 kJ mol-’ for NaBr and NaI, respectively, where the thermodynamic reference state is the solid halide. The solvation enthalpies derived from these values are -265.6*9.9 and -225.0k7.9 kJ mol-’ for bromide and iodide ion, respectively. The salts are considered to dissolve in the metal as the dissociated ions, solvated by liquid metal, and the solutions show large deviations from ideal but small deviations from regular behaviour.16 The solubilities of potassium chloride in liquid potassium and in

lo l1

l2

l3 14

Is l6

W. R. Jerez, V. S. Bhise, S. DasGupta, and C. F. Bonilla, Proc. Symp. Thermophys. Prop., 6th, 1973, p. 353. V. S. Bhise and C. F. Bonilla, Proc. Symp. Themophys. Prop., 6th, 1973, p. 362. J. W. Chung and C. F. Bonilla, Proc. Symp. Themophys. Prop., 6th, 1973, p. 397. R. N. Newman, Ignition Combustion Sodium-Review, 1972, RD/B’/N229. V. A. Polykhalov and V. F. Prisnyakov, Atomnaya Energii, 1973, 35, 51. C. Wagner, Acta Met., 1973, 21, 1297. P. J. Gellings, A. Van der Scheer, and W. J. Caspers, J.C.S. Faraday 11, 1974, 70, 531. C. G. Allan, Report 1973, TRG-Report-2458.

Inorganic Chemistry of the Main-group Elements

4

solutions of potassium (20 and 30 atom %) in lead have been determined. Samples of the metallic melt were drawn through porous glass filters and converted into aqueous solutions, and the chloride ions were determined mercurimetrically, using diphenylcarbazone as indicator. The solubility of KCl increases in both solutions with increasing temperature, but dilution of potassium with lead causes a sharp decrease in the solubility of KCl. The low-temperature data for potassium are probably all that exist at present, and they are provided in Table 1.” Table 1 Solubility (s) of potassium chloride (mole ‘/o salt) in liquid potassium TemperaturePC s/(mole ‘/o salt) TemperaturePC . s/(mole YO salt) 158 180 183 214 240 3 10

7.4 x lo-’ 9.4 x 1 0 - ~ 1.02 x 1.25 x lo-’ 1.26 X lo-’ 2.98 x lo-’

370 390 395 508 600 625

5.10 X lo-’ 1.25 x lo-’ 1.26 x lo-’ 5.56 X lo-’ 1.71 3.30

The high-temperature physical properties of the sodium coolant and oxide fuel used in fast nuclear reactors have been reviewed, and the review includes enthalpy, heat capacity, vapour pressure, density, surface tension, viscosity, thermal conductivity, and speed of sound measurements. l 8 In the control of impurities in liquid-sodium coolant loops, analytical methods for measuring the impurity content have been reviewed.” Instruments for monitoring specific impurities, e.g. 0, H, and C, in sodium have been covered in another review on instrumentation for monitoring liquid sodium in nuclear reactors.” Fission products produced in Na-K coolant, and which form oxides, are present as a fine suspension, which tends to deposit on transition-metal surfaces. The deposited material, which can be radioactive, can be removed by water.’l The state and behaviour of the non-metals oxygen, hydrogen, and carbon in liquid sodium are currently under investigation. Preliminary results from concentration measurements on oxygen and hydrogen suggest that the ion 02-exists in the solution and reacts with hydrogen, the excess being converted into sodium hydride, thereby affecting the equilibrium pressure.22 The general equation: log S = 6.2571 - (2444.5 K/T) has been derived for the solubility of oxygen in liquid sodium by combining additional data with previously published results. The equation provides an

’’ V. Busse-Macukas,

A. G. Morachevskii, S. I. Statsenko, L. V. Rorisova, and V. I. Markin, Zhur. priklad. Khim., 1973, 46, 2300. l 8 M. G. Chasanov, L. Leibowitz, and S. D. Gabelnick, J . Nuclear Materials, 1973, 49, 129. lY H. Ullmaun, Kernenergie, 1974, 17, 5. ’O D. J. Hayes, J. Phys. (E), 1974, 7, 69. 2 1 R. A. Davies and J. Drummond, J. Brit. Nuclear Energy SOC., 1973, 12, 427. 2 2 K. Furukawa and H. Katsuta, Bussei Kenkyu, 1970, 13, 418.

Elements of Group I 5 enthalpy of solution of 11.184 kcal mol-' for oxygen in the metaLZ3The determination of traces of carbon and oxygen in sodium and caesium has been described, based on the reactions "C(y,n)"C and 160(y,n)150,respec8 bremsstrahlung tively, induced by irradiation of Na and Cs with ~ 3 MeV for 5 and 2 minutes, respectively. Because the half-lives of "C and "0 are 20.3 and 2.03 minutes, respectively, the sample can be etched free of surface contamination after irradiation. The method enables determination of oxygen and carbon concentrations as low as 0.3 p.p.m." Corrosion of transition metals by liquid alkali metals continues to be of interest. In the absence of dissolved oxygen in sodium, the solubilities of iron, nickel, and chromium in the alkali metal are slight. In the early stages of corrosion of stainless steel, corrosion rates are high, decreasing asymptotically to a steady-state value. Corrosion rate increases linearly with oxygen content in the liquid Similarly with vanadium in sodium. At 600°C the ternary oxide Na,VO, was observed on the surface of vanadium after immersion in sodium containing dissolved sodium oxide. The compound was identified by X-ray powder diffractometry, which was recorded through a matrix of sodium. Vanadium oxides were detected beneath the ternary oxide layer, and the change in lattice parameter of the vanadium substrate indicated the occurrence and amount of oxygen in solid Specific transition-metal oxides also react with sodium to give ternary oxides. Thus Nb& NbO,, NbO, and Ta205react at 400 and/or 600 "C to produce cubic Na3M04(M = Nb or Ta) together with M as equilibrium product^.^' Sodium vapour reactions appear less straightforward. Sodium gas at 3.3 x lo-' Torr reacted progressively with increasing temperature with a-Fe203and a- or P-NaFeOz to produce mixtures of metallic iron with (a) unidentified phase, (b) Na,,Fe,O,,, and (c) Na,FeO,. The magnetic properties and paramagnetic resonance spectra indicated that FeI'I exists in these compounds. Attempts to synthesize the unidentified phase in the pure state from reactions of sodium The bemonoxide, Na20, with NaFeO, and Fe,-, 0 were haviour of liquid potassium towards vanadium oxides has been assessed and compared with that of sodium and of lithium. The oxides V,Os and VO react at 63 "C,V203at 180 "C, but VO does not react below 400 "C, the maximum temperature studied. Potassium converted VO, into KVO, whereas v205 and V 2 0 3gave VO and KVO,, but both these compounds were oxidized by dissolved K,O to produce K3V04.29 The rate of reaction of hydrogen with stirred liquid sodium has been investigated at constant volume over the temperature range 160-295 "C and at pressures from 5.0 to 33.0 kN m-'. The rate of absorption is proportional to J. D. Noden, J . Brit. Nuclear Energy SOC.,1973, 12, 329. C. Engelmann, F. Nordmann, and G. Tinelli, Report 1973, CEA-CONF-2330. 2 5 J. R. Weeks and H. S. Isaacs, Adu. Corrision Sci. Technol., 1973, 3, 1. " M. G. Barker and D. J. Wood, J. Less-Common Metals, 1974, 34, 215. 27 M. G. Barker, A. J. Hooper, and D. J. Wood, J.C.S. Dalton, 1974, 55. '* A. Tschudy, H. Kessler, and A. Hatterer, Compt. rend., 1973, 277, B, 687. 29 M. G. Barker, A. J. Hooper, and R. M. Lintonbon, J.C.S. Dalton, 1973, 2618. 23

24

6

Inorganic Chemistry of the Main -group Elements

hydrogen pressure, confirming a first-order reaction. The activation energy for the reaction was 69.0 f 8.0 kJ mol-’, compared with previously reported values of 72.4, 71.6, 69.1, and 41.9 kJ m01-l.~’Previous work on the kinetics and thermodynamics of both the sodium-hydrogen and sodium-hydrogenoxygen systems has been reviewed, and possible reasons are suggested for the observed differen~e.~‘ The solubility of hydrogen (0.03-1 p.p.m.) in sodium has been redetermined by means of a meter based on the diffusion of hydrogen through a nickel membrane. The results, which include data of other workers, are summarized by the equation: log(S/p.p.m. by weight) = 6.067 - (2880 K/T) For unsaturated solutions the amount of hydrogen in solution is governed by the pressure. Over this region the Sievert’s constant, K , is slightly affected by temperature and is given by the equation:32 log(K/p.p.m. T0rr-l”)

= 0.860 - (122.0 K/T)

A new type of battery is described which utilizes alloys of lithium with lead, zinc, or tin as anode, fused LiCl-KCl as electrolyte, and chlorine as cathode. Liquid lithium alloys are used instead of pure lithium since they are more dense and sink below the electrolyte. The e.m.f. of this cell is much lower than in the conventional lithium-chlorine battery but cell structure is simpler, and the operating temperature and self-discharge rate are much lower.33 Lithium anode electrochemical cells can be made to operate at room temperature by using electrolytes of lithium salts in solvents such as POC13, SOCl,, and SO,Cl,. The solvents are compatible with both lithium and strong oxidants, including Cl,, CuF,, (CF),, and WO,, which can therefore be used as cathode materials.,, Further room-temperature lithium cells have been studied which employ solutions of LiBCl, in POC1, and of LiAlC1, in SOCl, as electrolytes. A novel feature of these cells is that during discharge the solvents POCl, and SOCl, are electrochemically reduced and behave as soluble cathode^.,^ The Dow sodium-sulphur battery is more conventional, and operates at 300°C with a high current and voltage effi~iency.,~ The alkali metals have a role to play in ammonia synthesis. The K,O promoter in the conventional NH, synthesis catalyst enhances the chemisorption of nitrogen and causes a hydrogen-promoted dissociation of the N, 30

31

32

33

34

35

36

A . C. Whittingham and M. R. Hobdell, Report 1973, RD/B/N-2548. A. C. Whittingham, Report 1973, RD/B/M-2546. D. R. Vissers, J. T. Holmes, L. G. Bartholme, and P. A. Nelson, Nuclear Technol., 1974, 21, 235. Z . Takehara, S. Morimoto, Y . Ito, and S. Yoshizawa, Intersoc. Energy Convers. Eng. Conf., Conf. Proc. 7th, 1972, p. 63. J. J. Auborn, K. W. French, S. Leiberman, V. K. Shah, and A . Heller, J. Electrochem. SOC., 1973, 120, 1613. W. K. Behl, J. A . Christopulos, M. Ramirez, and S. Gilman, J. Electrochem. SOC., 1973, 120, 1619. C. A. Levine, R. G. Heitz, and W. E. Brown, Intersoc. Energy Conuers. Eng. Conf., Conf. Proc. 7th, 1972, p. 50.

7

Elements of Group I

molecule. The electropositive promoter, metallic potassium deposited from the vapour phase on to pure iron, increased the rate of ammonia synthesis by a factor of ten. An extraordinarily high activity was obtained with promoted Ru supported on active carbon, although Ru was inactive without K. The effectiveness of alkali metals increased in the order Na
3 Alloys and Intermetallic Compounds Limits of miscibility have been determined between lithium and potassium from 63 to 500°C. Generally, lithium is less miscible with potassium than with sodium; the tendency to separate into two immiscible liquids with lithium increases from sodium to caesium. In Li-K, between 63 and 180 "C, a K-rich liquid phase is in equilibrium with solid lithium, while two immiscible liquid phases are present above 180"C. The solubilities S/(p.p.m. by weight) of K in liquid Li, and of Li in liquid K, determined by chemical analysis of the immiscible phases, are given, respectively, by:38 log(S/p.p.m. by weight) = 5.50 - (1362 K/T) and

log(S/p.p.m. by weight) = 6.09- (1837 K/T)

The Li Knight shift has been determined over the full composition range for Li-Mg alloys and the Mg Knight shift measured for Mg-rich alloys." A new phase, Li3Al,, is reported in the Li-A1 system. The reaction of the correct proportions of the elements in an iron vessel at 600 "C under argon, followed by stepwise cooling, produced trigonal-rhombohedra1 Li,Al, with space group R3m, a = 4.508, c = 14.259 A, Z = 3, and d(expt) = d(ca1c) = 1.48. The structure is a variant of b.c.c. packing, with layers of A1 in corrugated rings.4o Thermodynamic properties of Li-Ga liquid mixtures have been studied by measuring the e.m.f. of the Li 1 LiC1-LiF Li-Ga cell. The activities, activity coefficients, integral and partial free-energy functions, excess free-energy, and entropy changes at 750 "C are presented in diagrams. Negative deviations from Raoult's law were observed at 4-80 atom YO lithium. The maximum value of the enthalpy of mixing, AH, = -5500 cal (g atom)-', corresponds to a 1:1stoicheiometric ratio, and it is concluded that maximum ordering in the liquid is achieved at the LiGa compound composit i ~ n . Similar ~l thermodynamic entities have been determined for lithium in bismuth from an analogous concentration cell, using Li-Bi molten alloys at 5 10-560 "C containing 2.8-36.0 atom YO Li. Negative deviations from

I

37 38

39 40

A. Ozaki, K. Aika, and Y. Morikawa, Catal., Proc. Int. Congr. 5th 1972, 1973, 2, 1251. F. J. Smith, J. Less-Common Metals, 1974, 35, 147. G. F. Lynch, M. J. Stott, and A. R. Williams, Solid State Comm., 1973, 13, 1675. K. F. Tebbe, H. G. Von Schnering, B. Rueter, and G. Rabeneck, Z. Natwrforsch., 1973, 28b, 600.

41

S. P. Yatsenko, E. A. Saltvkova, V. N. Diev, and L. N. Rykova, Zhur. fiz. Khim., 1973, 47, 2417.

8

lnorgunic Chemistry of the Main -group Elements

ideality were observed, in agreement with the nature of the phase diagram." Liquid Li-Bi alloys show a transition from conducting to semiconducting behaviour at ca. 4 atom '/O Bi.43 The Na-K phase diagram obtained under high pressure has been used to show that the entropy change on melting pure sodium or pure potassium is almost independent of pressure over a substantial range. Peaks which occur in the liquidus curves at high pressure near 67 atom '/O K are probably due to chemical association forming NaK2.44In the K-Cs system, the thermophysical properties reflect the formation of KCs in the liquid phase.45 The Rb-Ga phase diagram has been determined by thermal, X-ray, and chemical analyses. Two compounds were observed; RbGa,, peritectically formed at 354 "C, and RbGa,, m.p. 620 "C. RbGa is orthorhombic, a = 6.01, b = 11.13, and c = 6 . 1 6 A . The enthalpies of formation of RbGa5 and RbGa, are Two compounds have -3.42 f0.24 and -4.2 f0.3 kcal mol-', re~pectively."~ also been identified in the Cs-Ga system. CsGa, is rhombic, with a = 6.05, b = 11.16, and c = 6.18 A, and it forms peritectically at 426 "C. CsGa, is also rhombic, with a = 5.64, b = 9.84, and c = 5.90 A, and it melts at 590 "C. In the K-Ga system, the solubility of K in liquid G a up to 510 "C has been determined as: log(S/atom "/o) = 0.57 - [ 1250("C/T)] The compound KGa3 decomposes at 512 "C into solid KGa, (m.p. 595 "C) and liquid gallium. The standard enthalpies of formation of CsGa,, CsGa,, KGa2,and KGa3are -4.40, -2.3, -3.9, and -2.9 kcal mol-', re~pectively.~' The results have been reported of a comparative study of the measured electrical resistivities of liquid alkali metals and alloys, and the theoretical predictions for this quantity obtained within the diffraction The composition dependence of the Knight shifts in Na-Cs, Na-Rb, K-Rb-Cs, and Na-Rb-Cs liquid alloys has also been examined.49 Addition of small quantities of rubidium (0.3-4.51 atom %) to liquid sodium increases the electrical resistivity almost linearly with increasing solute concentration. With increasing temperature from 100 to 1100 "C, the effect of rubidium on the resistivity of sodium progressively diminishes.'" Addition of the solutes Hg, T1, and Pb increases the resistivity of liquid potassium linearly with both increasing concentration and temperature. The unit increases in resistivity/pfl cm (atom ' / O ) - ' , are 8.80, 9.85, and 15.8 for Hg, T1,and Pb, 42 43

44

45

46

47 48 49

A. I. Demidov and A. G. Morachevskii, Elektrokhimiya, 1973, 9, 1393. P. Ionannides, Nguyen Van Tran, and J . E. Enderby, Prop. Liquid Metals. Proc. Int. Conf., 2nd 1972, 1973, p. 391. A. B. Bhatia, N. H. March, and L. Rivaud, Phys. Letters (A), 1974, 47, 203. E. E. Shpil'rain, V. A. Tomin, D. N. Kagan, A. M. Belova, I. F. Krainova, G. A. Krechetova, V. I. Shkerrnontov, and S. N. Skovorod'ko, Teploenergetika, 1973, 26. S. P. Yatsenko, K. A. Chuntonov, and S. 1. Alyamovskii, Izvest. Akad. Nauk S.S.S.R., Metal., 1973, 233. S. P. Yatsenko and K. A. Chuntonov, Izuest. Akad. Nauk S.S.S.R., Metal., 1973, 182. W. Van der Lugt and A. J. Dekker, Physica (Utrecht), 1973, 69, 148. J. L. Van Hernmen, S. B. Van der Molen, and W. Van der Lugt, Phil. Mag., 1974, 29, 493. V. A. Savchenko and E. E. Shpil'rain, Teplofiz. Vys. Temp., 1973, 11, 671.

Elements of Group I 9 respectively.” Electrodiffusion measurements in molten Na-TI mixtures indicate that the charge on thallium ions in the liquid is close to three.’* The capillary-reservoir technique was used to measure electrotransport in Na-K, Na-Rb, and Li-Ag liquid mixtures. Calculations showed that a wide variety of electrotransport behaviour is expected with large or small effects, with or without migration reversals, and with little or appreciable variation with c o m p ~ s i t i o n .In ~ ~liquid sodium, both radioactive tracers ”Na and 19’Au accumulate at the anode under a potential gradient. The mobility of 19’Au, however, was approximately twice that of 22Na.54 The temperature and concentration dependences of the work function, 4, have been determined from photoemission on Na-Rb, Na-Cs, and K-Cs liquid mixtures. The ease of removing an electron from sodium increases linearly with increasing solute concentration at 25 “C when adsorption processes do not play a role. In the case where surface adsorption of the component with lower 4 occurs, the isotherms deviate from linearity. Where a compound, e.g. NazCs, is formed, a minimum exists in the Thermodynamic properties of Na-Mg and K-Mg molten alloys have been determined from e.m.f. measurements. At 700 “C, the solutions exhibit strong positive deviation from ideality, and solubility is limited between the components. The solubility of sodium in liquid magnesium increases from 2.1 at 638 to 2.7 atom Yo at 700°C. The maximum solubility of K in liquid magnesium at 700°C is 1.0 atom YO. The formation of liquid Na-Mg solutions is endothermic, with an enthalpy of solution of 80-240 cal (g at~m)-l.’~ Similar e.m.f. measurements on liquid Na-K showed relatively small positive and negative deviations from ideality of K activity and only negative deviations of Na activity, The enthalpies, entropies, and free energies ’Of the molten solutions at 500 “C reflected the formation of Na2K, and the formation of the solutions is accompanied by a volume c ~ n t r a c t i o n . ~ ~ E.m.f. measurements were used again to establish the partial thermodynamic , and A S of K-Pb melts at 600 “C. The system characteristics AG, A T C e S sAH, exhibited positive deviation from ideality in these parameters that was compatible with the nature of the phase diagram.” 4 Solvation of Alkali-metal Ions

Aqueous Solvation.-A review deals with ion solvation in both aqueous and non-aqueous media and covers thermodynamic aspects, electrical conductivity, viscosity, transport coefficients, and n.m.r. spectra. Factors affecting the T. Itami and M. Shimoji, Bussei Kenkyu, 1970, 13, 409. A. I. Pertsin and D. K. Belashchenko, Izuest. Akad. Nauk S.S.S.R., Metal., 1973, 115. ” D. A. Rigney, Report 1973, COO-2037-14. ” T. Persson and A. Lodding, Z . Naturforsch., 1973, 28a, 1972. 5 5 Yu. I. Malov and M. D. Shebzukhov, Elektrokhimiya, 1973, 9, 815. 56 M. F. Lantratov, Zhur. priklad. Khim., 1973, 46, 1982. 57 M. F. Lantratov, Zhur. priklad.’Khim., 1973, 46, 1485. V. Busse-Macukas, A. G. Morachevskii,’S. I. Statsenko, and V. I. Markin, Izuest. V.U.Z., Tsuet. Met., 1974, 17, 30. ” 52

10

Inorganic Chemistry of the Main -group Elements

stoicheiometry of the solvation complex are A further review is given of the knowledge of solvation from the kinetics of ionic association and from the investigation of electrolytes in mixed solvents.60Neutron-diffraction measurements made on solutions of the compounds NaCl, BaCl,, and NiCl, in heavy water show that the multiple-pattern method previously used for determining the partial structure iactors of simple liquids can be applied to aqueous solutions.61 Using a b initio and CND0/2 (complete neglect of differential overlap) methods the hydration energies of the ions Li', Na', F-, and C1- have been calculated for solvation by 1, 2, 4, and 6 water molecules. The hydration energy is given by AE = EA*(HZO), - (EA*+ nEHzO),where EA*(HZO), is the calculated energy for the hydrated ion, E A + is that of the water molecule, and n is the hydration number. For Li+(H,O), the AE's from the a b initio and CND0/2 calculations were similar (-88.5 and -86.9 kcal mol-') but the experimental value is -59.8 kcal mol-'. For Li'(H,O), A E was very sensitive to the basis set chosen for the a b initio calculation and ranged from -45.5 to -32.7 kcal mol-'. The CND0/2 method provided a value of -45.0 but the experimental value is -34 kcal mo1-1.62Self-diffusion coefficients of water molecules in aqueous solutions of the compounds RbBr and RbI at 25 "C have been determined by the spin-echo method. Both salts increase the mobility of H,O molecules, indicating a negative hydration of Rb' ions. The number of H,O molecules around the Rb' ion calculated from the dependence of the self-diffusion coefficient on the electrolyte concentration is 6."' Complexing between thorium nitrate and alkali-metal nitrates MNO, (M = Li, Na, K, NH:, or Cs') increases with the atomic number of M. Conductometric, potentiometric, surface tension, density, and viscosity measurements of alkali-metal nitrates and Th(NO,), in aqueous solutions are consistent with the hypothesis that the cations M have a primary hydration number of 6, with twelve H,O molecules in the second hydration shell. During titration the second shell is gradually destroyed owing to progressive replacement by an equivalent number of NO; ions. The minimum mobility shown by Li' among Posthe alkali-metal cations is striking evidence of strong i~n-hydration.~, sible formation of MgCl', MgBr', and MgSCN' ion pairs is reported in aqueous perchlorate solutions. The changes in the activities yi of water and of positive and negative ions in 3M-(Na,Mg)ClO, when Na was replaced with Mg" have been measured by e.m.f. titrations and by vapour-phase osmometry at 25 "C. All data were consistent with the equation: z 59

log y, = A + B[Mg2+]

H. J. V. Tyrrell, in 'Essays in Structural Chemistry,' ed. A. J. Downs, Plenum, New York, 1971, p. 296. 6o H. Strehlow, W. Knoche, and H. Schneider, Ber. Bunsengesellschuft phys. Chem., 1973, 77, 760. 61 J. E. Enderby, W. S. Howells, and R. A. Howe, Chem. Phys. Letters, 1973, 21, 109. '* K. Bauge and A. Stogard, Acta Chem. Scund., 1973, 27, 2683. 63 M. I. Emel'yanov and V. P. Yagodarov, Zhur. strukt. Khim., 1973, 14, 919. h4 N. G . Zunjurwad, J. Shiuuji Uniu., 1972, 5, 39.

Elements of Group I 11 when taking ion-pair formation into account, where the constants A and B are different for anions and cations and z is the charge on the ion studied. The equilibrium constants for the formation of ion pairs are: MgCl' (log K, = 0.98), MgBr (log K, = -1.45), MgSCN' (log K, = -0.91).65 The symmetry of H,O molecules in hydrate shells of cations has been determined from the i.r. absorption of LiX (X = BF,, clod, I, or MnO,) and Y(BF4),6H20 (Y=Ca, Zn, or Cd). Differences in the antisymmetrical and symmetrical vibrations of O H groups, v3(B1) and v,(A,) respectively, decreased with decreasing symmetry of the H,O molecule from Czuto C,with increasing donor-acceptor interaction. The v3- vl value of Y(BF4),,6H,0 decreased in the direction Li>Ca>Zn>Cd. The symmetry of the H 2 0 molecule is reduced with increasing covalency of the cation-H,O bonding, and more favourable Y-OH2 - - - OH, groupings are formed.661.r. and Raman spectral data for water at various temperatures suggest that there is an equilibrium mixture of at least two components differing in the degree of hydrogenbonding, one with a free O H vibrational mode and another with hydrogenbonded O H at longer wavelength. A structure-breaking solute increases the number of non-bonded OH groups in water. At 37°C there is a greater number of free O H groups than at 25 "C. The addition of solute changes the fraction of non-bonded OH groups and the position of maximum intensity of any band due to these groups. Experimental spectra have been obtained for aqueous solutions of LiCl, NaCl, KC1, CsC1, and HCl and of LiN03, NaN03, KNO,, HN03, AgN03, LiClO,, NaClO,, AgClO,, and HClO,. Anions are generally structure-breakers whereas cations are structure-makers. Cations and anions appear to act independently of each other in modifying the structure of water, which depends on the size and charge of ion, and, in the case of transition metals especially, on strong specific interactions between the ion and one or more H,O m01ecules.~'A further near-i.r. study of the OH mode in water at 10, 25, and 40°C also indicates two types of water molecule; a non-bonded and a hydrogen-bonded species. At 25"C, an enthalpy change of 1.87k0.05 kcal mol-' is associated with this bondbreaking process. Changes in the spectra show that Li' and F- decrease the concentration of non-bonded H 2 0 molecules while the opposite is found for the other alkali-metal and halide ions. The relative order for the structurebreaking abilities of these ions is F- < C1- < Br- < I- and Li' < Cs' < Na' = Rb+
66

12

Inorganic Chemistry of the Main -group Elements

Table 2 Enthalpies of solvation ( - AH,",,,/kcalmol-') of some uni-univalent electrolytes in dioxan-water mixtures and amide solvents (a) Dioxan- Water Mixtures - AHZ,,/kcal

Lattice energy Salt

(- U/kcal mol-l)

LiCl NaCl LiC10, NaClO, Me,NBr Et,NBr Pr,NBr Bu,NBr

200.20 183.50 202.43 183.80 131.09 122.84 119.09 118.07

mol-'

20% Dioxan

44.5% Dioxan

64.5% Dioxan

209.66 182.90 -

210.41 183.33 206.23 178.88 125.02 120.78 116.48 113.39

211.31 183.78 207.66 180.80 125.99 120.45 115.80 112.53

-

125.23 120.97 118.19 117.00

( b ) Arnide solvents - AH,",,,/kcal mol-'

Salt LiClO, NaC104 Kclo, RbClO, CsC10, NH,CIO,

Lattice energy (- U/kcal mol-') (169.40) (153.80) (139.70) (134.90) (128.60) (136.10)

191.80 174.90 165.10 159.50 152.20 157.00

DMF

Formamide

N-Methylforrnamide

213.80 182.75 167.40 161.45 153.97 165.50

202.60 176.60 161.60 155.45 147.60 156.20

205.60 178.25 163.60 156.80 149.10 158.55

behaviour of both salts is explained by a mechanism of 180" hops of the protons in the structural water. The activation energies for this process are 10 and 11 kcal mol-' for the lithium and barium salt, respectively. Near the melting point of LiC104,3H,0, a very slow motion of the water molecules (activation energy 20 kcal mol-') was The enthalpies of solution have been determined of the compounds LiC1, NaCl, Me,NBr, Et,NBr, Pr,NBr, and Bu,NBr in dioxan-water mixtures varying in composition from 20 to 64.5% dioxan. Standard enthalpies of solution were calculated from the extended Debye-Huckel equation and combined with the lattice energies of the salts to derive the solvation enthalpies, AH:,., shown in Table 2. Included in the table are solvation energies for perchlorates in amide solvents, which have been recalculated using a more appropriate value for the lattice energy than the original (in brackets), which was derived from the Kapustinskii e q ~ a t i o n . ~The " equivalent conductivity of the compounds LiC1, KCl, LiC104,KC10,, HCl, and HClO, in water-dioxan mixtures decreases with increasing dioxan concentration. Inflexions in conductivity occur at 20-40% dioxan, and the maximum

'' D. Scheller and B. '' Om. N. Bhatnager

Lippold, 2. phys. Chem. (Leipzig), 1973, 253, 105. and A. N. Campbell, Canad. J. Chem., 1974, 52, 203.

Elements of Group I 13 change in viscosity occurs at 2-3% dioxan. Apparently dehydration and subsequent solvation of Li', K', and C1- ions occur on addition of dioxan; ion * electrophoresis of alkali-metal pairs are formed at >40% d i ~ x a n . ~Paper ions shows that in aqueous solution the order of mobility is Cs' > Rb' > K' > Na' > Li', which is the order of the effective ion size due to hydration. In mixtures of water with methanol, however, the mobilities of Na and Cs decrease with increasing concentration of methanol; in pure methanol, Na' is The mean molar volumes of solutions of NaI and KI more mobile than CS+.~, in water-diethylamine mixtures have been measured, and the results indicate that the salts break the water structure. A complex is indicated in solutions of KI in the mixed solvent but not for NaI.73 The extracting ability of alkylphenols (C,, b.p. 279-290 "C) for alkali-metal ions from basic aqueous solution decreases from Cs to K.74The solvation of alkaline-earthmetal halides during extraction by isoamyl alcohol has been investigated. MgCl,, SrI,, and calcium halides were extracted as hydrated species. The extent of solvation by water or alcohol molecules in solvates of calcium halides in the organic phase increased in the order chlorides < bromides < iodides. SrCl, and SrBr, were not hydrated but SrI, was. The extreme behaviour of the metal iodides can be explained by donor-acceptor interaction of iodide ion with Some aqueous systems that have been investigated are listed in Table 3.76-83 Non-aqueous Solvation.-Structural radii and electron-cloud radii, together with lattice enthalpies and enthalpies of solvation of ionic crystals, have been re~iewed.'~ The free energies of transfer, AGtr(K+),of potassium ions from water to 14 non-aqueous solvents have been reported, and they were derived from measurements in an electrochemical cell assumed to have a negligible liquid-junction potential. The essentially electrostatic nature of its solvation allows K' to be used as a model for non-specific solvent-ion interactions. A 71

72 73 74

75

" 77

7R

79

81 82

83

84

T. Erdey-Gruz, E. Kugler, K. Vasse-Balthazer, and I. Nagy-Czako, Magyar Kim. Folybirat, 1973, 79, 397. T. Mitsuji art3 Y. Tsujii, Nara Kyoiku Daigaku Kiyo Shizen Kagaku, 1973, 22, 19. V. I. Obraztsoy, A. A. Khrustaleva, and S. I. Belyaeva, Zhur. fiz. Khim., 1973, 47, 2175. V. E. Plyushchev, Z. S. Abisheva, G. N. Klevaichuk, L. 1. Pokrovskaya, and A. M. Reznik, Izuest. Akad. Nauk Kazakh. S.S.R., Ser. khim., 1974, 24, 41. T. S. Kazas and K. S. Krasnov, Zhur. neorg. Khim., 1974, 19, 1375. S . M. Arkhipov, N. I. Kashina, and V. A. Kuzina, Zhur. neorg. Khim.. 1973, 18, 3148. P. S. Bogoyavlenskii and E. D. Gashpar, Zhur. neorg. Khim., 1973, 18, 3125. P. I. Protsenko, S. D. Merkulova, G. P. Protsenko, and V. N. Trufanov, Zhur. neorg. Khim., 1974, 19, 529. V. Mozharova, V. A. Borovayk, and E. N. Pavlyuchenko, Zhur. priklad. Khim., 1973, 46, 2560. V. K. Filippov, K. A. Agafonova, and M. A. Yakimov, Zhur. neorg. Khim., 1974,19,1663. A. G. Demakhin, I. E. Zimakov, and V. I. Spitsyn, Zhur. neorg. Khim., 1974, 19, 245. A. A. Opalovskii, T. D. Fedotova, 0. G. Tyrshkina, and G. S. VoronYna, Zhur. neorg. Khim., 1973, 18, 1672. L. A. Azarova, E. E. Vinogradov, E. M. Mikhailova, and V. I. Pakhomov, Zhur. neorg. Khim., 1973, 18, 2559. E. C. Baughan, Structure and Bonding, 1973, 15, 53.

Inorganic Chemistry of the Main -group Elements Table 3 Aqueous systems that have been investigated 14

Components NaN0,-RbNO, KNOy-KHCO, RbN02-Mg(NOz), NaC1-BaCl, KCl-BaCl, CsBr-CdB r, CsI-CdI, CsCl- Ag C1-MeOH NaHFZ-MHF, (M = Na, K, Rb, or Cs) LiI0,-KIO,

Compounds NaN0,,2RbN03

Ref. 76 77 78 79 79 80

3CsBr,CdBr, 7CsBr,3CdBr2 CsBr,CdBr, 3CsI,CdIz 2CsI,CdI, CsI,CdI,,H,O CsAgC1,

80

2LiI03,KIO,

83

81 82

comparison of AGtr(K+)with AG,,(Ag') detects some specific interactions of the Ag+ ion with solvents. In this respect there is a striking difference between AG,,(Ag+) of 99.5 kJ mol-' and AGtr(K+)of 26.8 kJ mol-' for Some free transfer from water to dimethylthioformamide (SDMF) at 25 oC.x5 energies/kJ mol-' of transfer from DMF to NN-dimethylthioformamide (SDMF) at 2 5 ° C are Li', 64.0; Na+, 50.2; K', 37.2; Cs+, 23.4; Tl', -4.2; Ag', -87.0. Some of these values can be interpreted in terms of general interactions of hard and soft cations with hard and soft basic solvents. A linear relationship, AGtr(M+)= rn AG,(M+), is approximately obeyed by many cations for transfer to a variety of Alkali-metal-ion-0-donor-solvent cages exhibit low-frequency bands in the i.r. spectrum characteristic of the cation-0 polyhedra. Similar bands are seen with N-donors. The bands can be used to establish the nature of cation co-ordination and serve as probes to examine ion-solvent interaction^.^^ An analysis of the i.r. spectra of ternary mixtures LiC104-S,-S, showed a preferential solvation of the Li' ion by NH, and methylamines (S,) in MeCN o r THF (S,) and by MeCN (S,) in MeN0, (SJ. The appearance of wide bands in the ion-cage vibration region is related to the formation of different species [Li(S,),-, ( S 2 ) i ] + . The Li+-solvent molecule interaction energy decreases when the number of S, molecules in the first solvation shell increases. The mean composition of the first solvation shell was obtained from intensity measurements of the molecules not bonded to the ions; in favourable cases (S, = ND, or MeCN), the solvation number ofthe Li' ion in the pure solvent 85 86 87

D. A. Owensby, A. J. Parker, and J . W. Diggle, J . Arner. Chern. SOC., 1974, 96, 2682. R. Alexander, D. A. Owensby, and A. J. Parker. Austral. J . Chern., 1974, 27, 933. C. N. R. Rao, J. Mol. Structure, 1973, 19, 493.

Elements of Group I

15

could be estimated. The solvating power of the different bases decreases in the order NH, > MeNH2> Me2NH> Me3N> MeCN > MeN02 and involves both donor-acceptor and ion-dipole interactions.8s The i.r. spectra of solutions of LiClO,, NaClO,, and Mg(ClO,), in MeCN at 2100-2400 and 900-1200 cm-' show a shift in the vibration frequencies of C%N and C-C groups of MeCN toward higher frequencies due to inter-ion and ion-solvent interactions. The shift is independent of concentration, with magnitudes of 10, 21, and 36 cm-' for Na', Li', and Mg", respectively. The optical density at the absorption maximum of the shifted bands was used to determine the number of molecules of MeCN in the solvation shell. For Li, Na', and Mg" these were 4, 4,and 6, respectively. Ion pairs forming in solutions of LiC104 and NaC10, were not solvated, but the ion pair [MgClO,]' was solvated by one MeCN The 'H n.m.r. spectra of 0.3-2M-MC1 (M = Li, Na, K, Rb, Cs, or NH,) solutions in formic acid revealed a shift of the H-C proton signal to lower fields due to solvation effects. The cation solvate structure has been discussed, and the estimated solvation numbers are 4 for Li' and N&+, 6 for Na' and K', and 8 for Cs+, in agreement with geometric con~iderations.~~ 23 Na n.m.r. measurements have been obtained on solutions of sodium salts in 1,1,3,3-tetramethylurea, 1,1,3,3-tetramethyleneguanidine, sulpholane, THF, DMF, formamide, EtOH, MeOH, pyridine, and EtOAc. Chemical shifts were measured relative to aqueous 3M-NaCl. The direction, magnitude, and concentration dependence of the chemical shifts were strongly influenced by the solvating ability or donicity of the solvents. Formation of contact ion pairs depended not only on the dielectric constants of the solvents but also on their solvating abilities." Alkali-metal salts in propylene carbonate were also studied by 23Nan.m.r. and by i.r. spectroscopy. Cation-solvent vibrational frequencies were observed for Li', Na+, K', Rb', Cs', and The effect of pressure upon the complexation of lithium fluorenide ion pairs with triglyme (L) in Et,O has been studied by spectrophotometry, which revealed the presence of three equilibria: Li'Fl-

+ L = L Li'Fl-

Li'Fl-

+ L = Li'L

K2

F1- K ,

L Li'Fl- = Li'L F1- K, Here Li'F1- denotes the tight pair of lithium fluorenide; L Li'Fl- represents the externally triglyme-complexed tight pair, and Li'L F1- is the loose pair, the ions of which are separated by a triglyme molecule. At high triglyme

'' A. Regis and J. Corset, 89

90 91

92

Canad. J . Chem., 1973, 51, 3577. I . S. Perelygin and M. A. Klimchuk, Zhur. fiz. Khirn., 1973, 47, 2025. B. M. Rode, Z . anorg. Chem., 1973, 399, 239. M. S. Greenberg, R. L. Bodner, and A. 1. Popov, J . Phys. Chem., 1973, 77, 2449. M. S. Greenberg, D. M. Wied, and A. I. Popov, Spectrochim. Acta, 1973, 29A, 1927.

Inorganic Chemistry of the Main-group Elements 16 concentration, additional equilibria became important:93

L Li'F1and

+ L = L Li'L

F1-

Li'L Fl- + L = L Li'L F1-

Density measurements on solutions of alkali-metal salts in methanol from 0 to 60 "C over a wide concentration range show that the structure-breaking effect of the salts decreases in the order NaC10, > NaI, NaBr and KI > NaI > L~I.~" In an extension of previous calculations on the lithium cation-ammonia system, the energy for the reaction: Li'

+NH, = Li'(NH,)

has been calculated from CND0/2 and ab initio methods to be AE = -91.9 and 53.6 kcal mol-', respectively. Closer agreement with published experimental data for the equilibrium Li-N distance, r, in Li'(NH,) was obtained by the ab initio method ( r = 1.98 %.) than by the CND0/2 method ( r = 2.19 A)." The electrical resistivity of lithium tetra-amine, Li(NH,)", at 10-100 K and the magnetoresistance at 4.2 and 1.66 K have been measured, using a probeless mutual-inductance technique. The resistivity shows several anomalies in the solid phase, one of which has also been observed in thermal measurements and is associated with a f.c.c.-h.c.p. phase change. A second change near 69 K has not been observed thermally and is attributed to a magnetic transition. It is concluded that Li(NH,)" is probably an uncompensated metal with a high proportion of free carrier^.'^ Spectra of the solvated electron have been determined at -55, -65, and -75°C from solutions of Na in liquid ammonia and from 0.08 mol 1-' solutions of NaI in this liquid by extrapolation to infinite dilution. The spectra are consistent with absorption by two species but rule out the possibility that the second absorber incorporates only a single solvated electron. The data support the assumption that the second absorber is a binary combination of solvated electrons which is produced at all three temperatures and in solutions of both Na and NaI in ammonia. Spectra reported earlier appear to be characteristic of the second absorber and not the solvated e l e c t r ~ n . A ~ ' Raman study of liquid NH,, ND3, and ND,H, and of solutions of NaI and NaClO, in liquid NH3, has been made in which resolution of the envelopes in the N-H and N-D stretching regions suggests a two-species nature for the solvent The fundamental vibrational frequencies of liquid ammonia are perturbed primarily by anion interaction, with one exception, the symmetrical bending 93 94

95

96

97 98

B. Lundg;en, S. Claesson, and M. Szwarc, Chemica Scripta, 1974, 5, 60. B. S. Krumgal'z, 1. P. Kikitina, and 1. V. Kudryavtseva, Zhur. fiz. Khirn.,1974, 48, 1048. A. Stogard, Acta Chem. Scand., 1973, 27, 2669. M.D. Rosenthal and B. W. Maxfield, J. Solid State Chem., 1973, 7, 109. G . Rubinstein, T. R . Tuttle, jun., and S. Golden, J. Phys. Chern., 1973, 77, 2872. A. T. Lemley, J . H. Roberts, K. R. Plowman, and J . J. Lagowski, J . Phys. Chem., 1973, 77,

2185.

Elements of Group I

17

mode, v,, which exhibits a strong cation dependence. Low-frequency bands which are assigned to the symmetrical stretching mode of the solvated cation were observed for Li', Na+, Mg", Caz+,S F , and Ba2+at 241, 194, 328, 266, 243, and 2 15 cm-', re~pectively.~~ Ammonia pressure-temperature diagrams at 50-60 "C have been constructed for the systems LiBr,NH, (SJ-NH,LiBr,2NH3 (S,) and LiBr,2NH3 (S,)-NH3-LiBr,3NH3 (S,). The same kinetic characteristics were found in the interfacial reactions S, + S, or S, + S, when they were studied alone or together, provided that the nucleation of the last solid was slow. When nucleation was rapid, the total rate measured was at most equal to that of the energetically favourable reaction.loOIn solutions of potassium amide in liquid ammonia, an anomalously large transparency in the i.r. spectrum was observed at 1500-2300 nm which showed up at high KNH, concentrations and high hydrogen pressures. This was attributed to production of the solvated electron according to: NH;

+fHz= e- +NH,

It is suggested that a complex is formed between e-, KNH,, and some NH, molecules which are strongly linked, so that the normal bands of NH, at 1500-2300 nm diminish in intensity."' The reaction shown is claimed to limit the decomposition of metal solutions in liquid ammonia.102

5 Compounds containing Organic Molecules or Complex Ions The determination of the molecular structure by X-ray diffraction of complexes of lithium, sodium, potassium, rubidium, and caesium has been reviewed.lo3The complexing properties of macrocyclic ligands, in particular, form the basis of a second review.lo4 One current series of studies of the complexes formed- between alkali-metal ions and macrocyclic polyethers aims to determine the type of bonding site which will hold a specific metal ion in a hydrophobic environment. In this context, dibenzo-24-crown-8 (6,7,9,10,12,13,20,21,23,24,26,27-dodecahydrodibenzo[b,n]-1,4,7,10,13, 16,19,22-octaoxacyclotetracosine)reacts with two molecules of potassium isothiocyanate, giving C2,H,,O,,2KNCS. This compound shows the novel feature of having two potassium ions attached to one cyclic polyether at adjacent binding sites, an aromatic-type bond to potassium, and double nitrogen bridging from thiocyanate ions across two potassium ions. The structure was determined by three-dimensional X-ray K. R. Plowman and J. J. Lagowskii, J. Phys. Chem., 1974, 78, 143. R. De Hartoulari and L. C. Dufour, Bull. Soc. chim. France. 1973. 11, 2923 E. Saito, Report 1972, CEA-CONF-2228.. lo* J. Belloni and E. Saito, Report 1972, CEA-CONF-2230. lo' M. B. Hursthouse, in Molecular Structure by Diffraction Methods', ed. G. A. Sim and L. E. Sutton (Specialist Periodical Reports), The Chemical Society, London, 1973, Vol. 1, p. 791. 104 C. Kappenstein, Bull. SOC.c h m . France, 1974, 89. 99

100

18

Inorganic Chemistry of the Main -group Elements

analysis from diffractometer data. Crystals are monoclinic, of space group P2/c, with 2 = 2 in a unit cell of dimensions a = 9 . 9 0 2 , b = 18.55, c = 8.573 A, p = 106.9'. The environment of the K' ion is shown in Figure 1. The K-0 distances range from 2.732 to 2.979 A,compared with 2.8502.931 8, in the dibenzo-30-crown-10 complex and 2.777-2.955 8, in the

Figure 1 Diagrammatic representation of the co-ordination about the K' ions. The plane of the ligand ring shows only oxygen atoms. The benzene rings belong to two other ligand molecules in the crystal. Bond distances/A

K-0(1) 2.732(6) K-N K-0(4) 2.778(6) K-N' N-C K-0(7) 2.898 (6) K-O(7') 2.979(6) S-C K-O(10') 2.825(6) N-S 3.41( 1) K . . . K' (Reproduced from J.C.S. Dalton, 1973, 2469)

2.88(1) 2.87(1) 1.18(1) 1.60(1)

2.78(1)

(benzo- 15-crown-S),K+ complex. In the other complexes the metal is completely enclosed by ten oxygen atoms. In this complex it is available for interaction with anion and solvent, or, as in the crystal, with another source of electron density. Dibenzo-24-crown-8 is intermediate in size between dibenzo- 18-crown-6 and dibenzo-30-crown-10, and it is considered to be too large for formation of a 1: 1 complex and insufficiently flexible to wrap round a potassium ion, with the result that the 2 : 1 complex forms even in the presence of excess of ligand."' The structure of [Na(C2,H3606)(HZ0)2]Br is monoclinic, space group P i , with a = 10.32, b = 11.34, c = 6.67 A, '"' M Mercer a n d M. R. Truter, J.C.S. Dalton, 1973, 2469.

Elements of Group I

19

a = 116" 42', f3 = 109" 48', y = 100" lo', d(obs) = 1.43, and d(ca1c) = 1.406 for 2 = 1. This compound, dicyclohexyl-18-crown-6 sodium bromide, contains a six-oxygen 18-membered ring, and, since six-oxygen-membered rings preferentially select K' over Na', is an example of a complex in which the cation is in a selectively unfavourable environment. As before, the sodium ion is at a centre of symmetry and surrounded by an approximately planar ring of the six oxygen atoms of one ligand, with Na-0 distances of 2.67-2.97 A. Two water molecules (at Na-OH2 distances of 2.34 A), one above and one below the plane, separate the Na' ions from the bromide ions, creating a hexagonal-bipyramidal arrangement about the cation. The H,O molecules form hydrogen-bonds to bromide ions, giving an infinite chain structure.106 An investigation of the effect of solvent, presence of water, and ratio of reactants on the isolation of complexes between LiX (X= Br, I, or NCS) with benzo-15-crown-5 (1) and of NaX and KX with (l), dibenzo- 18-crown-6 (2), dibenzo-24-crown-8 (3), and dibenzo-30crown-10 (4) has led to several new complexes, particularly those with two

-

Table 4 Summary of known compositions of LiX-, NaX-, and KX-crown ether complexes. Ratios are quoted as metal: ether Li

X= (1)

(2) (3) (4)

' I { I

K

Na A

Br

NCS

3

1:1,HzO l : l , H z O 1:1,HzO 1:1, 1.SH2O 1:l 1:2 1:2 2:2 1:1,H20 1:1,2H20 1:1,2H,O 1 ~ 11.5H20 , 1:1 111 l:l,HzO 1:1, HzO 2: 1 2: 1 2:1,H20 2:l I:1 - 1:1,H2O

metal atoms to one ligand. In principle, synthesis of the complexes is simple. The ligand and salt are dissolved in a common solvent, e.g. ethanol, and warmed. Crystals separate on cooling. The criterion for complex formation was the isolation of a new phase which (i) if unsolvated had a higher melting point than the polyether and (ii) did not absorb at the characteristic i.r. frequency of the polyether. The known compositions of LiX, NaX, and KX complexes with the four macrocyclic ethers are collected in Table 4. Two lithium compounds with (1) are established as monohydrated 1:1 complexes, the bromide and iodide. No complexes were formed between lithium salts and the larger macrocyclic ethers.lo7 A generalized picture of the sodium and potassium complexes is shown in Figure 2. Complexes have also been prepared where X is an organic anion obtained by the deprotonation of 2-nitrophenol, 4-nitrophenol, 2,4-dinitrophenol, 2,4,6-trinitrophenol, 2-hydroxybenzoic acid, 2,6-dihydroxybenzoic acid, 2nitrobenzoic acid, or 2-aminobenzoic acid. For potassium, complexes of the Io6

lo'

M. Mercer and M. R. Truter, J.C.S. Dalton, 1973,2215. N. S. Poonia and M. R. Truter, J.C.S. Dalton, 1973, 2062.

20

Inorganic Chemistry of the Main -group Elements Pol y ether

M e t a l Ion, M+

Potassium

Sodium

I I1

I11

IV

Figure 2 Schematic representation showing stoicheiometry of polyether-MX complexes and the conformation of the polyether in the lattice. Solid dot stands for metal ion and the loop for polyether. (Reproduced by permission from J . Arner. Chem. SOC., 1974, 96, 1012)

type 1l2K1+X-, [( 1)&]+[X, as.]-, I(1),Kl'[X,HXl-, and [( 1),K]'[X, (HX),]are isolated. These are of comparable stoicheiometry to those when X - = Br-, I-, or NCS-. A point of difference is that the organic anion more effectively dehydrates M', so that even sodium is dehydrated in complexes with (1) and (3). For (2), where complexes of Na' and K' are constantly monohydrated, M' makes an easy fit into the hole of polyether, and water is able to interact with it from the vacant axial direction."' Preliminary polarographic investigations have been made on [(2)K]'SCN- and [(5)K]'C1-, where (5) is l,lO-diaza-4,7,13,16,2 1,24-hexaoxabicyclo[8,8,Slhexacosane. The NaNCS complex of the macrotetrolide antibiotic nonactin (6)

Me

(6) nonactin lo' log

N. S. Poonia, J. Amer. Chern. SOC., 1974, 96, 1012. F. Peter and M. Gross, Compt. rend., 1973, 277, C, 907

/

A

Elements of Group I

21 crystallizes in the space group C2/c, in which a = 15.55, b = 19.59, c = 15.31 A, p = 90". The environment of the sodium cation in this complex, C40012HS4,NaNCS, is shown in Figure 3. The X-ray crystal structure shows that the Na' ion is co-ordinated by four carbonyl oxygen atoms at distances of 2.438 and 2.395& and by four ether oxygen atoms at distances of

23

23

Figure 3 Bond lengths and bond angles are indicated in the right part of the figure, torsion angles in the left part for the complex of nonactin with sodium thiocyanate. (Reproduced by permission from Helv. Chim. Acta, 1974, 57, 664) 2.791 8, for 0 - 4 , (2.877 A in K complex) and 2.744 8, for 0 - 1 2 (2.812 A in K complex). The cubic co-ordination by eight near-equidistant oxygen atoms previously observed in the corresponding K complex is thus deformed but requires only very small changes in the ligand conformation. The carbonyl oxygen atoms, with their less crowded surroundings, seem better able to approach the sodium ion. This preference may be attributed to stronger dipole interaction with carbonyl- than ether-oxygen atoms. The preference of the ligand for K' depends mainly on the change in coordination from eight equidistant oxygen atoms in the K' complex to only four first neighbours in the Na' complex.11o Complexes of alkali and alkaline-earth metals with tripod ligands have 1'

M. Dobler and R. P. Phizackeriey, Helv. Chim. Acta, 1974, 57, 664.

22

Inorganic Chemistry of the Main -group Elements

been investigated. For the alkali metals these are the 2,2',2"-trimethoxytriethylamine-sodium iodide complex [NaI,N(CH,CH20Me),] and the 2,2',2"-triethanolamine-sodium iodide complex [NaI,N(CH,CH,OH),]. The crystal structures, respectively, are orthorhombic, space group Pna 2,, with one molecule per asymmetric unit, a = 14.77, b = 7.560, c = 13.570 A,and triclinic, space group P i , with two molecules per asymmetric unit, a = 7.693, b = 7.559, c = 9.294 A,a = 102.16", p = 91.47", and y = 93.02'. The crystal structure of NaI,N(CH2CHzOMe), consists of discrete molecules in which the sodium cation is pentaco-ordinate, as shown in Figure 4. Each

c9

Figure 4 Environment of sodium in the complex NaI,N(CH2CH20Me), (Reproduced by permission from Acta Cryst., 1974, B30, 56) sodium is bonded to all heteroatoms of one ligand and to the iodide ion. The Na-N distance is 2.45 A,the mean Na-0 distance is 2.35 A, and the Na-I distance is 2.97A.l" In NaI,N(CHzCH20H),, the sodium ion is heptaco-ordinate. Two OH groups of each molecule bridge two Na' ions. Each Na' is thus bonded to the four heteroatoms of one ligand molecule, two oxygen atoms of a neighbouring ligand, and to the iodide ion (Figure 5). The co-ordination polyhedron is an octahedron, with a seventh atom on one of the faces. The distances Na-0, Na-N, and Na-I are 2.516, 2.610, and 3.286 A, respectively.''* Complexes of 1,4-anhydroerythritol (cis-3,4dihydroxytetrahydrofuran) with the formulae (C,H,O,),,NaI, C,H,O,,NaClO,, and C,HsO,,NaSCN have been prepared, The perchlorate complex is orthorhombic, space group P2,2,2,, with a = 12.77, b = 7.28, c = 17.69 A,and 2 = 8. There are two crystallographically distinct molecules in the structure but they are approximately alike, and both furanoid rings (7)

(7) 1,4-anhydroerythritol. 111

'12

J. C . Voegel, J . C. Thierry, and R. Weiss, Actu Cryst., 1974. B30, 56. J. C . Voegel, J. Fischer, and R. Weiss, Actu Cryst., 1974, B30,62

Elements

Group 1

23

Figure 5 The environment and co-ordination of Na in NaI,N(CH2CH,0H), (Reproduced by permission from Acta Cryst., 1974, B30, 62) have the same near-envelope conformation. About both Na atoms there is a distorted octahedron of oxygen atoms comprising three from different ClOi ions, one pair of hydroxyl-oxygens from one carbohydrate molecule, and the etheric-oxygen from another, as shown in Figure 6. The Na-0 distances fall within the range 2.29-2.33 A. The Na-O(ether) distances are 2.36 and 2.35A; Na-O(perch1orate) distances range from 2.37 to 2.59A. Three of the C10, oxygen atoms are co-ordinated both to Na and C1, but one oxygen atom of every ion is not bound to Na, and these atoms with only one bond pack together but at distances too great to imply the

Inorganic Chemistry of the Main -group Elements

24

Figure 6 Part of the infinite net showing the co-ordination about one of the two kinds of Na atoms. The sets of atoms differ only slightly in their co-ordination geometry. In every Cloy ion one of the 0 atoms is bound only to C1, and two such atoms are depicted, together with a neighbouring hydroxyl 0, the packing distances (dashed lines) being indicated numerically. (Reproduced by permission from Actu Cryst., 1974, B30, 1590) existence of a chemical linkage.'" An X-ray diffraction analysis of a single crystal of the LiBr complex of antamanide, cyclo (-Val-Pro-Pro- Ala-PhePhe-Pro-Pro-Phe-Phe-) (8), crystallized from acetonitrile, shows the Li' to 8 9 10 1 Pro-Phe-Phe-Val-Pro

I

2

I

(all

L-)

Pro-P he-P he--A la-Pro 7 6 5 4 3

(8) Antamanide

be pentaco-ordinate, with four ligands to the carbonyl-oxygens of Val', Pro', Phe", and ProRand the fifth ligand to the N atom of the solvate MeCN, as shown in Figure 7. The compound C,,H,,N,,O,,(LiBr)(MeCN),2MeCN,

'

l3

R.E. Ballard, A. H. Haines, E. K. Norris, and A. G. Wells, Acta Cryst., 1974, B30, 1.590

25

Elements of Group I ANGLES DEG. 0(1)Li0(3) 8 6 O(3)LiO(6) 89 0(6)Li0(8) 84 0(8)Li0(1) 93 NLiO 11 96 NLiOt31108 NLiO(6 96 N Li0(8\ 104

Figure 7 The distances and angles for the ligands to the pentaco-ordinated Li' in LiBr,(antamanide) (Reproduced by permission from J . Arner. Chern. SOC., 1974, 96, 4000)

has space group P2,, with a = 11.912, b=23.206, c = 13.864& p = 110'0 45'5. Antamanide forms alkali-metal complexes with a high selectivity for sodium over potassium ions, and the Na'-antamanide complex is most stable in a lipophilic environment. Eight peptide groups are in the trans conformation, while the Pro2-Pro3 and Pro'-Pro* peptide linkages are cis. This folding of the chain forms the cup in which the Li ion is located. The co-ordination is completed by a MeCN molecule rendering a completely hydrophobic cage round the lithium. The complex differs from the K+-nonactin and K'-valinomycin complexes in several respects. K' occupies the centre of the complex, and is symmetrically surrounded by six or eight oxygen atoms, with K-0 distances ranging from 2.7 to 2.8A. Furthermore, the nonactin ring folds into a figure resembling the seams of a tennis ball and completely encases the K'. The valinomycin forms a thick doughnut-shaped ring round K'. The Li+-antamanide complex, however, has much less symmetry, only an approximate two-fold axis, and much bulkier side-groups. The Li' ion resides in a shallow cup, with all ligands from the ion to the antamanide moiety on one side, while the other side of the Li is strongly co-ordinated to a solvent molec~le."~ ,The o-nitrophenolatobis( 1,10-phenanthroline) alkali metal complexes are the principal products when excess 1,lO-phenanthroline is added to the reaction solutions of the alkali-metal o -nitrophenolate in ethanol. The. sodium complex, C,,H,,N,NaO,, and rubidium complex are both triclinic, space group P , with a = 10.436, 11.413; b = 10.062, 13.214; c = 14.867, 10.068 A; a = 96.99, 99.06; p = 104.02, 114.80; y = 119.12, 101.78'; d(obs) 1.37, 1.48; and d(ca1c) 1.364, 1.494 for 2 = 1, respectively. In the sodium complex, the cation is six-co-ordinate, interacting with the three propellor-like chelating ligands in pseudo-32 symmetry, and the structure is of monomeric units, as shown in Figure 8. Each phenanthroline molecule is chelated to the cation through two N atoms; for molecule (A), Na-N distances are 2.491 and 2.506A, but for molecule (B) the Na-N distances are more dissimilar, at 2.444 and 2.557 A. The o-nitrophenolate ion is co-ordinated through the phenolic oxygen and one of the nitro-group oxygen atoms at Na-0 I. L. Karle, J . Amer. Chem. SOC.,1974, 96, 4000

26

Inorganic Chemistry of the Main -group Elements

Figure 8 o-Nitrophenolatobis-( 1,lO-phenanthr0line)sodium: one monomer unit, shown with two neighbouring phenanthroline ligands (Reproduced from J.C.S. Dalton, 1973, 2347) distances of 2.281 and 2.421 A. The rubidium complex has a similar pseudo-three-fold symmetry of the chelating ligands but, with a larger co-ordination sphere, the cation also accepts co-ordination with a second 0nitrophenolate ion, which thus bridges cations about a centre of symmetry, as shown in Figure 9. In the rubidium complex, the corresponding dimensions about the cation are: Rb-N, 3.059 and 3.082A in phenanthroline molecule (A), and 3.045 and 3.016A in molecule (B); Rb-(phenolic 0) is 2.838 and Rb-(nitro-group 0) is 2.949A. The extra Rb-0 distance is 3.190 A, and it therefore represents a weaker interaction than the The structure of the potassium salt of a cyclo-octatetraene dianion has

Figure 9 Diagrammatic representation of the co-ordination in a dimer unit of o-nitrophenolatobis-(1, 10-phenanthr0line)rubidium (Reproduced from J.C.S. Dalton, 1974, 2347)

"' D.

L. Hughes, J.C.S. Dalton, 1973, 2347.

Elements of Group I

27

been determined. The yellow air-sensitive crystals of potassium diglymebis(l,3,5,7-tetramethylcyclo-octatetraene), [K{(MeOCH,CH,),0}]2[CsKMe4], crystallize in space group P?(C:), with a =9.757, b = 10.026, c = 8.793A, a =97.15, p = 112.35, and y = 109.95", and with d(calc)= 1.16 for Z = 1. As predicted by the Huckel theory, this 1 0 ~ electron system is aromatic, with eight-fold molecular symmetry, and average C-C bond lengths of 1.407A. The complex exists as a discrete ion trimer. The anion ring lies sandwiched between two complexed potassium cations, as shown in Figure 10. The opposite side of each potassium ion is

Figure 10 A perspective drawing of [K{(MeOCH2CH2)20}]2[CsH4Me4]. Hydrogen atoms are not shown. (Reproduced by permission from J. Amer. Chem. SOC., 1974,96, 1348) co-ordinated by the three ether oxygen atoms of diglyme at an average distance of 2.835A. All the K-C bond lengths are equal, and average 3.003A. This is slightly shorter than the average K-C distance of 3.16 %, observed in the related compound [K{(MeOCH,CH,)O}][Ce(C,H8),] reported last year (Vol. 2, p. 31), whereas the K-0 distance is slightly longer.l16 Solvates containing two and six molecules of diglyme have been detected from solubility measurements of rubidium gallium hydride, RbGaH,, in diglyme from -66 to 115 "C. Above 80 "C, only unsolvated salt exists.'" 116

S. Z. Goldberg, K. N. Raymond, C. A. Harmon, and D. H. Templeton, J. Amer. Chem. SOC., 1974, 96, 1348. T. N. DymovaandYu. M. Dergachev, Izuest. Akad. Nauk S.S.S.R., Ser. khim., 1973,2659.

28

Inorganic Chemistry of the Main -group Elements Alkali-metal salts can be precipitated from aqueous solution by complexing with racemic 2,3-di(p-aminophenyl)butane. The complexes contain cations co-ordinated by six amino-N atoms to give an infinite threedimensional polymeric structure. Strong cation-nitrogen bonding exists, but cation-anion interaction is weak.'" The crystal structure of NaCl(dpb) is hexagonal, space (dpb = p7p'-diamino-2,3-diphenylbutane, C16HZON2) group R%, with a = 21.172, c = 17.004 A, d(obs) = 1.178, d(ca1c) = 1.176 for Z = 6. The amine nitrogen atoms are hexaco-ordinated to the Na ions, with a bond length of 2.608 A.119Hexamethylphosphoramide solvates of alkali-metal salts have been prepared and characterized by elemental analysis, melting points, and i.r. spectra. The wavenumber of the P-0 stretch of L decreased by 15-25 cm-I upon co-ordination to the metal ions in the compounds LiXL [L = (Me,N),PO; X = C1, SCN, ClO,, NO,, or BF,], NaXL [X = I, SCN, or ClO,], LiX,2L [X = SCN or OAc], NaSCN,2L, and LiX74L [X = Br or C104].'20A further example of a salt-neutral molecule complex is provided by KIs(xanthotoxin)z,which is triclinic, space group P?, with a = 9 . 5 9 , b=11.09, c = 7 . 9 6 A 7 a=118.1, p = 8 6 . 7 , y=114.5", d(expt) = 2.11, and d(ca1c) = 2.11 for 2 = 1.lZ1In solution, 23Na n.m.r. spin-lattice relaxation-time measurements of aqueous Na' mixtures with cysteine, aspartic acid, and citric acid show that only a weak interaction of cysteine and aspartic acid with Na' exists, whereas a Na' complex is formed with the citrate ion.lZ2The electrostatic binding of Na' and K' by fulvic acid in aqueous solution has been measured with cation electrodes at 25 "C. The binding equilibria were studied by acid-base titrations, and distinct binding regions in the titration curves were The compounds LiC10,,3NH2OH, LiNO,,NH,OH, Mg(N0,)2,2NH,0H, and Ca(N03)2,2NHzOH have been prepared by the reaction of the anhydrous salts with hydroxylamine in organic solvents. Hydroxylamine is co-ordinated to the metal through the oxygen atom.124Potentiometric titrations of glucose and fructose with uni- and bi-valent cations show marked changes in potential at stoicheiometric hexose :salt ratios attributed to complex formation. For 1: 1 univalent cations the complexing ability was in the order Na'>K'>Li' for glucose but K+> Na' > Li' for fructose. For bivalent cations the corresponding orders were Sr2+> Mg2+> Ca2+> Ba2' and Ca" > Sr2' > Ba" > Mg2+.lZ5 Alkali-metal tetrahydroborates react with zinc chloride in ether, THF, or diglyme (DG) to give NaZn(BH,),,Et,O (9), NaZn(BH4),,2THF (lo), and RbZn(BH4),,2DG (11). The complexes (9) and (10) are soluble in all three

118

N. P. Marullo, J . F. Allen, G. T. Cochran, and R. A. Lloyd, Inorg. Chern., 1974, 13, 1 15. L. A. Duvall and D. P. Miller, Inorg. Chem., 1974,13,120. D. C. Luehrs and J . P. Kohut, J. Inorg. Nuclear Chem., 1974, 36, 1459. M . Kapon and F. H. Herbstcin, Nature, 1974, 249,439. T. L. James and J . H. Noggle, Btotnorg. Chem., 1973, 2, 69. D. S. Gamble, Canad. J . Chem., 1973, 51, 3217. Zh. G. Sakk and V. Ya. Rosolovskii, Zhur. neorg. Khirn., 1974, 19, 621. A. J. Dangre, J. Univ. Poona, Sci. Technol., 1973, No. 44, p. 217.

'lY

122

lZ4

Elements of Group I

29

solvents and (11) is soluble in diglyme. Generally, M,Zn(BH4)2+ndecomposed thermally to MBH, and Zn(BH4)2.126 The crystal structure of the complex bis[NN-ethylenebis(salicy1ideneiminato)copper(~~)]per chlorato-sodium-p -xylene, NaClO,[ Cu(salen)],p C6€&Me2,has been determined from three-dimensional X-ray data. Crystals are monoclinic, space group C2/2, with a = 24.44, b = 11.283, c = 14.766 A, p = 101.22", d(obs) = 1.56, d(ca1c) = 1.47 for 2 = 4. (Several compounds of this type were described in Vol. 2, p. 31). The structure contains discrete Na' ClO; ion pairs in which the cation is approximately octahedrally co-ordinated by two oxygen atoms of the perchlorate ion at 2.55 A and by four oxygen atoms from the two Cu(sa1en) complexes so that the sodium ion shares these oxygen atoms with a copper atom, Na-0 2.36, Cu-0 1.90 A. This is shown in Figure 11. The p-xylene molecule fills a

Figure 11 One Na'ClO; ion pair and the two chelating [NNethy lenebis(salicytideneirninato)]copper(11) molecules as seen along the crystallographic a-axis. The directions of the two-fold axis, b, and of the c-axis are indicated. (Reproduced from J.C.S. Dalton, 1974, 841) space in the loosely packed structure, and there are no atoms within 3.5 A of the The crystal and molecular structures of trisodium 6phosphogluconate dihydrate. Na3P0,C,H,o0,,2H,0, have been determined by X-ray analysis. The crystals are monoclinic, space group P 2 , , with

lZ7

V. I. Mikheeva, N. S. Kedrova, and N. N. Mal'tseva, Izvest. Akad. Nauk S.S.S.R., Ser. khim., 1974, 512. H. Milbum, M. R. Truter, and B. L. Vickery, J.C.S. Dalton, 1974, 841.

30

Inorganic Chemistry of the Main -group Elements

I"/ 2

I

Figure 12 The co-ordination polyhedra of the K' ions in potassium gluconate monohydrate. (a) Form A. (b) Form B. (Reproduced by permission from Acta Cryst., 1974, B30, 1421)

D-

a = 11.588, b = 5.876, c = 9.859 A, p = 97.57", and Z = 2. The structure is held together by an extensive hydrogen-bond network as well as sodium-ion co-ordination by oxygen from several 6-phosphogluconate ions.'*' Neutrondiffraction data have been used to refine the crystal structures of the A and B forms of potassium D-gluconate monohydrate, KC,H,,O,,H,O. These are space groups P2,2,2,, P2,; a = 8.220, 9.353; b = 17.840, 7.357; c = 6.717, 7.229 A; Z = 4 and 2 for the A and B forms, respectively, and p = 109.39" for the B form. The gluconate ion is straight-chained in A but bent in B. The cations are in voids between the puckered sheets of hydrogen-bonded anions and appear to have a secondary role in determining the structure. The cation co-ordination is shown in Figure 12. Interestingly, the cations 128

G. D. Smith, A . Fitzgerald, C . N. Caughlan, D. A . Kerr, and J . P. Ashmore, Acta Cryst.,1974, B30, 1760.

Elements of Group I

31

are as far removed as possible from the carboxylate oxygens, which are not included in the first cationic co-ordination shell. The eight nearest K-0 distances include 0-3, 0 - 4 twice, 0 - 6 , and two water (W) oxygens at distances between 2.61 and 3.24A. The fact that the charge on the gluconate ion (12) is, at least formally, located on the carboxylate group would not be deduced from observing this ~ t r u c t u r e . ~ ~ ~ OH OH H OH

I I

I l

I l

I 1

OOC-C-C-C-C-CHZOH H HOHH (12) D-gluconate ion

In lithium manganese(I1) ethylenediaminetetra-acetatepentahydrate, LizMn(edta),SH,O, the alkali-metal cation is tetrahedrally co-ordinated by oxygen atoms from two water molecules and two carbonyl groups. The average Li-0 distance is 1.94 A. The compound is ,orthorhombic, with a = 11.62, b = 9.04, c = 16.72 A, d(obs) = 1.67, and d(ca1c) = 1.69 for 2 = 4.130 The analogous compound, LiFe(edta),3H2O, has space group P2,/b, with a = 8.82, b = 17.80, c = 9.75 A, y = l l O ” , 2 = 4, and d(ca1c) = 1.92.13’ Co-ordination of the alkali-metal ion to oxygen atoms takes a very distorted trigonal-bipyramidal arrangement in the compound sodium nitrilotriacetatocopper(I1) monohydrate, N~CUN(CH~COO)~,H,O [or NaCu(nta),HzO]. By means of bonds to four different nta groups (Na-0 distances 2.2822.372 A) and a water molecule (Na-0 distance 2.288 A) the sodium ions help bind the structure together (Figure 13). The co-ordination by water of sodium rather than copper is not unusual. In other structures where CU(II), Na, and H,O are all present, such as sodium glycylglycylglycinocuprate(11) monohydrate and disodium glycylglycylglycinocuprate(I1) decahydrate, only the sodium ions are co-ordinated by water, even though the octahedron about the copper is incomplete. Similarly with LiCu(nta),3Hz0. Presumably, in each case chelation of the CU” ion neutralizes the ionic charge, so that subsequent stabilization of the structure is best achieved by coordination of HzO to alkali metal. The structure of NaCu(nta),H,O is orthorhombic, with a = 9.899, b = 12.565, and c = 7.548 A, and it belongs The crystal and molecular structures of to the space group P212,21.’32 guanosine 3’,5’-cyclic monophosphate sodium tetrahydrate, C,oH,,N,O,PNa,4Hz0, have been determined by single-crystal X-ray diffractometry. The crystals are orthorhombic, space group P2,2,2,, with a = 18.664, N. C. Panagiotopoulos, G. A. Jeffrey, S. J. La Placa, and W. C. Hamilton, Acta Cryst., 1974,

’” 13’

13’

B30, 1421. N. N. Anan’eva, T. N. Polynova, and M. A. Porai-Koshits, Zhur. strukt. Khim., 1974,15,261. N. V. Novozhilova, T. N. Polynova, M. A. Porai-Koshits, N. I. Pechurova, L. I. Martynenko, and Ali Khadi, Zhur. strukt. Khim., 1973, 14, 745. S. H. Shitlow, Inorg. Chem., 1973, 12, 2286.

32

Inorganic Chemistry of the Main -group Elements

Figure 13 A perspective view of the packing in NaCu(nta),H,O. The view, looking down the b-axis, selectively shows the basic nta structure, the metal atoms to which it bonds, and complete Cu and Na co -ordinations. (Reproduced by permission from Inorg. Chem., 1973, 12, 2286)

b = 7.384, c = 12.706 A, d(obs) = 1.66, and d(ca1c) = 1.665 for 2 = 4, assuming one Na' ion and four H 2 0 molecules per nucleotide. The bond distances and angles in the ribose ring show significant differences from those of the common nucleotides. The phosphate ring is locked into the chair position. The crystal packing consists of alternating layers of stacked nucleotides, with the interstitial holes filled by sodium-water distorted octahedra. The Na' ion is co-ordinated to six water molecules at distances from 2.32 to 2.68 A, thus barring them from direct contact with the anionic phosphate oxygens (Figure 14). Adjacent octahedra share edges to generate an infinite water hole impregnated with sodium ions, which are 3.77 A apart. The water molecules (W) around the Na' ion are in turn linked to the

Elements of Group I

33

Figure 14 The water-to-sodium bond distances and the water-to-nucleotide hydrogen- bond distances in guanosine 3',5'-cyclic monophosphate sodium tetrahydrate. (Reproduced by permission from Acta Cryst., 1974, B30, 1233) ribose 2'-hydroxy-group, the base N-7, 0 - 6 , and N-2 atoms, and the phosphate oxygen 0-7 by hydrogen The crystal structure of Na4H,Mo,PzOz,(H,0)lo has been determined from three-dimensional X-ray diffraction data. The compound is monoclinic, space group P2,/n, with a = 26.388, b = 13.661, c = 8.041 A, and /3 = 91.37", 2 = 4.The structure is built up from [HzMo,P,0,3]4- anions, Na' cations, and H,O molecules. The complex anions are linked together by direct sodium bridges (0-Na-0) in the y - and z-directions, forming infinite layers parallel to the yz-plane. These layers are held together by 0-Na-H,O-Na-0 linkages. Each Na' ion is surrounded by six oxygen atoms (water and ligand-group oxygens) to form an octahedron which is distorted. 134 Trisodium gallium trimetaphosphimate dodecahydrate, Na,Ga12Hz0, also consists of complex anions Ga[(PO,NH,)]:-, Na' (P306N3H3)2, cations, and water molecules. The crystals are triclinic, space group P i , with a = 8.729, b = 9.902, c = 8.716 A, a = 97.84", /3 = 87.88", y = 93.45", and 2 = 2. The trimetaphosphimate groups are terdentate ligands joined to Ga atoms through 0 atoms. Between Na3(H20),2fragments and complex anions there are Na-0 A. K. Chwang and M. Sundaralingam, Acta Cryst., 1974, B30, 1233. B. Herman, Acta Chern. Scand., 1973, 27, 3335. 135 V. I. Sokol, M. A. Porai-Koshits, L. A. Butman, I. A. Rozanov, and V. R. Berdnikov, Izuest. Akad. Nauk S.S.S.R., Ser. khim., 1974, 485, 133

134

34

Inorganic Chemistry of the Main-group Elements

Alkali-metal and ammonium salts of halogenoacetic acids have been studied. In aqueous lithium chloroacetate-chloroacetic acid mixtures, the unstable compound 2CH,ClC0,Li,CH2C1C0,H is formed. From CHC1,C0,Li-CHCl,CO,H-H,O mixtures the two compounds 2CHCl,CO,Li,CHC12C02H,H20and CHC1,CO,Li,2CHC1,CO2H are formed. In CCl,CO,LiCCl,CO,H-H,O mixtures, the phase 2CC1,CO2Li,CC1,CO,H is produced. 136 The phase diagrams of the ternary systems of the three chloroacetic acids with their sodium salts have also been investigated. With CH,ClCO; no definable compound was isolated, but a stable monohydrate and unstable dihydrate of CHCl,CO,Na were formed. With CCl,CO;, the trihydrate of CCl,CO,Na, decomposing easily into the dihydrate, and the salt CCl,CO,Na,2CC1,C02H were isolated. '37 The structure of potassium hydrogen bis(dichloroacetate), KH(CHCl,CO,),, is monoclinic, space group P2,/c, with lattice parameters a = 6.246, b = 23.187, c = 9.325 A, p = 106.73", d(obs) = 1.90, and d(ca1c) = 1.935 for Z = 4.138Rubidium hydrogen trichloroacetate, RbH(CCl,CO,),, has space group I2/c, with a = 9.395, b = 6.410, c = 10.293 A,/3 = 93.70", cf(obs) = 1.23, and d(ca1c) = 2.28 for z =4.13' The 7Li n.m.r. spectrum of lithium acetate dihydrate, LiCH3C0,,3H,0, indicates a tetrahedral configuration round the lithium ion, confirming recent 'H n.m.r. and X-ray results.140The compounds MHO(CH,CO,), (M = Na c r K) are both monoclinic, with space group P2,/c, four units in the cell, and cz=6.990, 7.107; b=9.610, 10.451; c=8.434, 8.558A; p = 103.34, 101.44" for the sodium and potassium compounds, respectively. These metal hydrogen oxydiacetates contain infinite chains of oxydiacetate anions linked by a short hydrogen-bond. The chains are cross-linked by the alkali-metal cations.141 These features are common to the rubidium analogue but this is tetragonal, space group I42d, with a = 8.481, c = 18.099 A, and 2 = 8.'", Infinite chains of hydrogen malonate residues are also linked by short unsymmetrical hydrogen-bonds in sodium hydrogen malonate, which is monoclinic, space group P2,/c, with a = 6.664, 6 = 7.522, c = 9.337 A, P = 100.69", d(obs) = 1.80, and d(ca1c) = 1.78 for 2 = 4.'"' Compounds of sodium with P-diketones HL (HL = 2,4-acetoacetoxylide, acetoacet-o-anisidide, benzoylacetanilide, or benzoyl-rn-nitroacetanilide) have been prepared in dry ether-ethanol solvent. The compounds NaL were identified by analysis and U.V.and i.r. The thermal decomposition of sodium acetylacetonate and its dihydrate, NaL and NaL,2H,O (HL = acetylacetone), between 25 and 1000 "C proceeds in two J . Pokorny, 2. Chem., 1973, 13, 303. J . Pokorny, Z. Chem., 1973, 13, 439. '31 I . Leban, Cryst. Struct. Comm., 1974, 3, 245. 139 L. Golic and P. Lazarini, Cryst. Struct. Cornrn., 1974, 3, 411. 14(1 S. V. Bhat, A . C. Padmanabhan, and R. Srinivasan, Acta Cryst., 1974, B30, 846. 141 J. Albertsson, I. Grenthe, and H. Herbertsson, Acta Cryst., 1973, B29, 1855. lilZ J. Albertsson, I. Grenthe, and H. Herbertsson, Acta Cryst., 1973, B29, 2839. S. N. Rao and R. Parthasarathy, J.C.S. Perkin 11, 1974, 683. 1 4 4 A . D. Taneja, J. Inorg. Nuclear Chem., 1973, 35, 3617.

13'

13'

Elements of Group I 35 stages. Thermogravimetric analysis shows that NaL yields Na,CO, at ca. 400°C, and this is superseded by NazO at ca. 700°C. NaL,2H20 also lost the expected amount of water in two well-defined Preliminary X-ray diffraction data for caesium and potassium dipicrylaminates indicate triclinic structure, space group P1 or P i , with a=8.77, b = 11.50, c = 8.77 A, a = 88" 30', f3 = 104" 45', y = 91" 20', d(exp) = 2.14, d(ca1c) = 2.23 for Z = 2 for the caesium salt, and monoclinic, space group P2, Pm, or P2/m, with a = 11.05, b = 12.30, c = 13.02 A, y = 93" 20', d(expt) = 1.75, d(ca1c) = 1.82 for Z = 4 for the potassium ~ a 1 t . Disodium l~~ maleate monohydrate, Na2C4H204,H,0,crystallizes from DMSO-water mixtures in the form of thick plates of space group C2/c, with a=20.979, b = 10.004, c =6.369& p = 100.15". The maleate dianions are held together in an edge-to-edge manner by Na' and H 2 0 bridges. The Na+ ions reside in distorted square-pyramidal sites formed by five oxygen atoms at an average Na-0 distance of 2.402 A.147 Crystals of sodium 7,7,8,8-tetracyanoquinodimethanide, Na(tcnq), Na(C12H4N,),are triclinic, with space group C i and lattice constants a = 6.993, b = 23.707, c = 12.469 A, a = 90.14", p = 98.58", y=90.76", and Z = 8 . The tcnq ions form a columnar structure along the a-axis with alternating interplanar distances of 3.21 and 3.49 A. Accordingly, tcnq dimers are recognized in the structure. The Na' is surrounded octahedrally by six nitrogen atoms of different tcnq ions at distances between 2.419 and 2.565 A, compared with cubic 8-co-ordination of the cation by nitrogen in Rb(tcnq) and K(tcnq), although the structures of the potassium and sodium salts are most closely ~e1ated.l~'In Rb(tcnq) (form 11) the interplanar spacing in the dimer is much wider than in the other salts. Moreover, Rb(tcnq) is triclinic, space group P i , with a = 9.914, b = 7.196, c = 3.390 A, a = 92.70°, p = 86.22", y = 97.73", and d(ca1c) = 1.757. 149

6 Alkali-metal Oxides Ab initio quantum-mechanical calculations have been made for the two lowest electronic states of the Li02 molecule. For isosceles triangular configurations, the 'A2 state is the ground state, with equilibrium geometry r(Li0) = 1.82 A and O(0-Li-0) = 44.5". The 2B2state is predicted to lie 14 kcal mol-' higher, with r(Li0) = 1.76 A and O(0-Li-0) = 46.5". For C,, symmetry the 'lJ state bond distances were predicted, r(Li-0)= 1.62 A and r ( 0 - 0 ) = 1.35 A. There appears to be little or no barrier The decomposition of anhydrous lithium between the C2uand C,, 14'

146

147

1 4 '

' 4 1

E. Boschmann and W. A. Althaus, Proc. Indiana Acad. Sci., 1973, 82, 156. V. P. Chalyi, G. N. Novitskaya, Yu. P. Krasan, L. L. Shevchenko, and A. T. Pilipenko, Zhur. strukt. Khim., 1974, 15, 159. M. N. G. James and G. J. B. Williams, Acta Cryst., 1974, B30, 1257. M. Konno and V. Saito, Acta Cryst., 1974, B30, 1294. I. Shirotani and H. Kobayashi, Bull. Chem. SOC. Japan, 1973, 46, 2595. S. V. O'Neil, H. F. Schaefer, and C. F. Bender, J. Chem. Phys., 1973, 59, 3608.

36

Inorganic Chemistry of the Main -group Elements

hydroxide under a pressure of lopsTorr at 360 "C for 48 h, and at 640730 "C for periods s 1.3 h, in Ni, Mo, Nb, or Ta containers is reported to produce a residue of chemical composition Li30,. This is considered a single compound belonging to the orthorhombic system, with a = 10.84, b = 12.84, and c = 10.36 A, and it was also formed on evaporating excess lithium metal from a solution of oxygen in liquid lithium at S730"C for 1.5 h at ca. Torr. Under these conditions the monoxide Li,O rather than Li,O, had previously been assumed to be the residue.lsl The Li,ONa,O binary system has been investigated and exhibits the following features (compositions in YO Li,0):152eutectic, 770 "C; P-Na20 (ss) (10%)+ Li,O (ss) (85%) =liquid (24%) eutectoid, 675 "C; a-Na,O (ss) (5%)+Li,O (ss) (90%) = P-Na20 (ss) (10%) peritectic, 980 "C; P-Na20 (ss) = y-NazO (ss) + liquid ( 1O0/o) or metatectic, 960 "C; P-Na20 (ss) +liquid (10%) = yNa,O (ss). The e.s.r. spectra of the molecules NaO,, KO,, RbO,, and CsO,, isolated in rare-gas matrices, are consistent with an ionic M'O; model of isosceles symmetry, in accord with recent vibrational spectra. The e.s.r. spectrum for CsO, also shows evidence for an inversion of the uppermost occupied molecular orbital which can be attributed to a slight covalent mixing of the oxygen valence orbitals with the inner-shell p-orbitals of the meta1.lS3The Raman spectrum of clear single crystals of sodium superoxide, NaO,, shows a molecular mode in addition to the usual vibrational modes. The Raman line at 1156 cm-' at 300 K corresponds to the usually found frequency of the 0; ion, and confirms that NaO, is ionic. Structural phase transitions at 230 and 201 K agree with previous findings by specific-heat and X-ray analy~is."~ The solubility of potassium superoxide KO, in liquid ammonia has been measured from -75 to -40°C. Equilibrium in the system was slow, taking 3 . 5 4 h. At -40 "C, 0.024*0.003 g of 92% pure KO, dissolves in 100 cm3 of ammonia.155On heating mixtures of KO, with lithium perchlorate, cation exchange occurs between the components, accompanied by liberation of oxygen. At 250-300°C the mixture melts with evolution of oxygen. At 360-500 "C, perchlorate is also decomposed. These melts are recommended for oxygen preparation."" The reactions of potassium peroxide K,O, with halogens in carbon tetrachloride and DMSO have been studied. The K,O, was derived from the thermal decomposition of KO,. In CCl,, K,O, did not react, but in DMSO, bromine and iodine are converted into KBr and KI, respectively. S. Stecura, J. Less-Common Metals, 1973, 33, 219. G. Papin, Compt. rend., 1973, 277, C , 677. 1 5 3 D. M. Lindsay, D. R. Herschback, and A. L. Kwiram, Chem. Phys. Letters, 1974, 25, 175. l S 4 M. Boesch, W. Kaenzig, and E. F. Steigmeier, Phys. Kondens. Mater., 1973, 16, 107. l S 5 A. E. Kharakoz, E. Romashov, T. B. Durnyakova, S. V. Bleshinskii, 1. I. Vol'nov, and S. A. Tokareva, Izuest. Akad. Nauk Kirg. S.S.R., 1974, 51. V. Brunere, A. Salta, and I. I. Vol'nov, Latu. P.S.R. Zinat. Akad. Vestis, Kim. Ser., 1973, 397. 15'

lS2

Elements of Group I 37 Chlorine did not react, and this was attributed to the formation of more stable adducts between the halogen and DMS0.lS7 Matrix reactions of the alkali-metal atoms with ozone have been followed by i.r. spectroscopy. At 15 K, deposition of alkali-metal atoms and ozone at high dilution in argon produced very intense bands at 800cm-' and weak bands at ca. 600 cm-', which showed appropriate isotopic shifts for assignment to v, and v 2 of the 0; ion. There was evidence for a symmetrically bound cation to O,, with C,,, symmetry. The symmetric interionic stretching mode was observed at 281 cm-l for Cs'O;. The reaction between these constituents produced the CsO fundamental at 322 cm-' and Cs,O at 457 cm-l. Simultaneous photolysis using a mercury arc was required to yield the LiO absorption at 752 cm-' from the Li-0,-argon-matrix r e a c t i ~ n . " ~ E.s.r. spectra of nitrogen-matrix-isolated caesium monoxide and 2 ground state. This state rubidium monoxide molecules confirmed the ' results from mixing of the filled (n - l)p alkali-metal orbitals with the 2p oxygen orbitals, analogous to the innerrshell bonding in the isoelectronic XeF and KrF X-Ray diffraction reveals that rubidium and caesium superoxides undergo a phase transition from the tetragonal (I4/mmm) to the cubic (Fm3m) structure on heating at 130-150 and 130-200 "C, respectively. Analogous to the 0; ion in the P-phase of KO, or NaO,, the 0; ion in RbO, and CsO, either does not have a preferred orientation or is rotating. The f.c.c. crystal of RbO, has a = 6.35 8, at 150 "C, and that of CsO, has a = 6.62 A at 200 "C.16' The thermal decomposition of CsO, has been investigated from 320 to 440 "C, and covered the composition range cs202.06~s203.96.There is no formation of solid solution or sesquioxide over this composition range. The reaction path was deduced to be:

2cs02 (s) = cszo2 (s) + 0

2

(g)

For caesium peroxide, over the composition range 320-500 "C, the reaction path is:161

at

2cs20, (s) = 2 c s 2 0 (s) + 0, The standard free energy of formation, AGO, of caesium monoxide has been

calculated from experimental results as -308.42 f 1.18 kcal mol-'. To permit practical thermodynamic calculations to be made at higher temperatures, experimentally determined heat capacities at 5-350 K have been extrapolated to 763 K, the m.p. of C S , ~ ,and a table of extrapolated thermodynamic functions, including AGO, is now available up to 763 K.16' lS7

lS8 159 160 16' 162

Dz. Pelca, V. Brunere, and J. Sauka, Latu. P.S.R. Zinat. Akad. Vestis, Kim. Ser., 1973, 390. R. C. Spiker, jun., and L. Andrews, J. Chem. Phys., 1973, 59, 1851. D. M. Lindsay, D . R. Herschback, and A . L. Kwiram, J. Chem. Phys., 1974, 60, 315. V. Ya. Dadarev, A. B. Tsentsiper, and M. S. Dobrolyubova, Kristallografiya, 1973, 18, 759. S. P. Berardinelli and D . L. Draus, Inorg. Chem., 1974, 13, 189. H. E. Flotow and D. W. Osborne, J. Chem. Thermodynamics, 1974, 6, 135.

38

Inorganic Chemistry of the Main -group Elements

The standard enthalpy of formation, AH", of caesium monoxide is -82.69 f 0.28 kcal mol-'. This value was derived from a solution-calorimetry study of high-purity Cs,O dissolving in excess water to form CsOH (aq).163

7 Alkali-metal Halides The purification of alkali-metal halides has been re~iewed.'~" Interaction potentials of many ion pairs have been calculated assuming that the electron density of the combined system is equal to the sum of the two separate ionic electron densities. The Coulomb-energy contribution to the interaction was calculated directly from the charge distribution of the nuclei and the assumed electron density. The non-Coulombic part of the interaction energy was calculated from the electron density, using the electron-gas energy expression in terms of the local density. The ions treated are those of Li, Na, K, Rb, Be, Mg, and Ca and F, C1, and Br. The predicted molecular bond energies, bond lengths, and vibration frequencies agree well with existing experimental data when the calculated ion-ion interaction potentials are applied to the theory of these halide Precise values have been obtained for the outer electronic bands of the alkali-metal fluorides by using 40.81 eV U.V. photoelectron spectroscopy. An approximate difference of 1.1eV between experimental and Born-model, binding energies is attributed to polarization eff ects.166Similarly for the alkali-metal ch10rides.l~~ (See also Vol. 2, p. 39.) The He I photoelectron spectra of the gaseous molecules of CsF, LiBr, MCl, MBr, and MI (M = Na, K, Rb, or Cs) have been obtained by using a high-temperature spectrometer equipped with an internally located laser-beam-heated sample oven. The spectral bands were assigned MO origins by use of MO calculations, spin-orbital splitting considerations, band-intensity relations, polymer-formation tendencies, and mass-spectrometric data.16*The He I photoelectron spectra of the caesium halides have been measured. They exhibit two well-separated sets of peaks; one derived from orbitals formed from halogen p-orbitals and the other from Cs p-orbitals. Each set of bands was analysed by including spin-orbit interaction within the degenerate ll states and subsequently and C(l/z)states. This analysis is a prototype for all between the IIcl/z) alkali-metal halides and has been used in conjunction with ab initio calculations to construct potential-energy curves for LiC1, LiBr, LiI, and KF. These cases suffice to characterize the variations in the photoelectron 163 164

166

167

J. L. Settle, G. K. Johnson, and W. N. Hubbard, J. Chem. Thermodynamics, 1974, 6, 263. F. Rosenberger, Ultrapurify, 1972, p. 3, ed. Z . Morris. Y. S. Kim and R. G. Gordon, J. Chem. Phys., 1974, 60, 4332. R. T. Poole, J. Liesegang, R. C. G. Leckey, and J. G. Jenkin, Chem. Phys. Letters, 1973, 23, 194. R. T. Poole, J. G. Jenkin, R. C. G. Leckey, and J. Liesegang, Chem. Phys. Letters, 1973, 22, 101. T. D. Goodman, J. D. Allen, jun., L. C . Cusachs, and G. K. Schweitzer, J. Electron Spectroscopy Related Phenomena, 1974, 3, 289.

Elements of Group I

39

spectra and mass spectra for all the alkali-metal halides.'"' High-resolution X-ray photoemissions of LiF, NaF, NaC1, NaBr, NaI, KF, KCl, KBr, and KI are reported. The valence-band spectra are compared with previous spectra of the isoelectronic series Group IV, 111-V, and 11-VI crystals. Features of the spectra evolve systematically in proceeding from the Group IV elements to the I-VII crystals. An analysis of this trend leads to the interpretation of the structure of the outermost halogen p band in the less ionic cases as being due to band effects rather than to spin-orbit splitting."" Infrared absorption spectra have been measured for NaF and KF isolated in solid argon. The fundamental modes of these species and the B3",BZu, and B1, modes of (NaF), and (KF), are assigned assuming a planar rhomboid structure of D,, symmetry for the dimers.171Surface ionization of lithium and its halides has been studied by a double-filament technique. At relatively high temperatures the temperature dependence of the lithium surface ionization current from all molecules studied was identical with that from lithium. Incomplete dissociation of LiCl can account for Li ionization threshold temperatures well above that for surface ionization of Li atoms. Dissociation energies of 4.8k0.1 eV for LiCl(g) and 4.3 *0.1 eV for LiBr(g) were The equilibrium ionic forms in salt vapours have been studied. The concentration of M' and X- ions in the saturated vapours of MX (M = Na or K, X = halogen) at 850 "C is 107-1010 ions cm-3 and the ions ~ m - so ~ ,that the concentration of M,X+ and M,X- ions is 10'-lo" vapours exhibit measurable electric conductivity. The equilibrium constants for the gaseous reactions are as follows: KI = K++I-

I-= I + e 21 = I, K'+e-=K KI + I- = KI, KI + K+= K21+

lo-'" atm 3.386 x lo-' atm 3.272 X

43.18 atm-'

lo1' atm-' 1 . 9 0 6 ~lo3 atm-' 2.041 x lo' atm-' 2.196 x

and are calculated from existing thermodynamic functions for KI, K', I-, K21i, and KI;. The equilibrium constants, enthalpy, and entropy for the' reactions : MX = M + +Xand

3MX = M2X++ MX;

are also calculated for lithium, sodium, potassium, and caesium halides. The equilibrium constants increase in the order F < C l < B r < I for salts with a J. Berkowitz, J. L. Dehmer, and T. E. H. Walker, J. Chem. Phys., 1973, 59, 3645. S. P. Kowalczyk, F. R. McFeely, L. Ley, R. A. Pollak, and D . A. Shirley, Phys. Reu. (B), 1974, 9, 3573. 17' Z.K.Ismail, R. H. Hauge, and J. L. Margrave, J. Inorg. Nuclear Chem., 1973, 35, 3201. "* E.N. Sloth, M. H. Studier, and P. G. Wahlbeck, J. Phys. Chem., 1974, 78, 820.

169 170

Table 5 Complex halides that have been investigated Compound

Ref.

AZBMF6 Lattice constants for forty compounds (A, B = Li, Na, K, Rb, Cs, or TI; given M = Al, Ga, V, Cr, Fe, or Co)

180

M3A1F6 (M = Li or Na)

Direct fluorination of M,A1H6

181

LiAIF4, LizAIF5

Partial pressures in LiF-AIF, mixtures of complexes and of LiF and LizF. For LizAIH5= LiA1H4+ LiF at 109 K, AH = 58.7 kcal mol-' and AS = 30.4 e.u.

182

183

CsAIBr,, RbCsAI,Br, LiGaF,, (LiGaF4)z, Li2GaF5

Partial pressures above LiF-GaF, mixtures of complexes and of LiF, Li2F2,and Li3F3 at 869 K. Enthalpies/kcal mol-' of sublimation, AHs, and dissociation, AH:y8, are, respectively: LiGaF, = LiF + GaF,

62.1, 61.3

LizGaF5= LiF+ LiGaF, (LiGaF,), = 2LiGaF4

55.5, 60.9 46.0, -

184

MGaBr,, MGazBr7, (M= Rb or Cs)

Incongruent m.p.s/"C: RbGaBr,, 2 5 2 ; CsGaBr,, 320; RbGa2Br7, 125; CsGazBr7, 170.

185

CsSn"Ha1,

CsSnCI,, CsSnBrzC1, CsSnBr,, CsSnBrJ, CsSnBrIz, and CsSnI, all have cubic perovskite structure. Halogen n.q.r. spectra presented.

186

Unit-cell dimensions/A for Fm 3m crystals, and Sn-C1 bond lengths/A are 9.9818, 2.411; 10.0442, 2.421; 10.0961, 2.423; 10.3552, 2.423; 12.835, 2.402 for M = K , N K , Rb, Cs, and Me,N, respectively. The n.q.r. frequencies steadily increase with increasing cation size. Raman spectra. Tetrahedrally co-ordinated C1 by Sb converted into octahedral with increasing size and numbers of alkalimetal cation.

187

3KC1,2SbCI3 and RbCI,SbCI,

188

Orthorhombic, space group Pmcn, a = 7.630, b = 13.079, c = 18.663 A, Z = 4. Close packing of Cs and C1 atoms with Sb in octahedral holes.

189

= 7.644,

189

Cs,Bi,Cly

Orthorhombic, space group Pmcn, a b = 13.277, c = 6.84 A, Z = 4.

MzSbBrb

So Values are estimated as 118.3 and

190

109.0 cal K-' mol-' for M = Rb and Cs, respectively. 3CsBr,2BiBr3 and 3CsBr,BiBr3

3RbCI,BiC13, 7RbC1,3BiC13, and 3RbC1,2BiC13

Thermal stability up to 750 "C. Compounds decompose, giving BiBr, and CsBr. 3CsBr,2BiBr3 passes through 3CsBr,BiBr, stage. Thermal stability. 7RbC1,3BiC13 d. 140 "C to 3RbCI,BiC13 and 3RbC1,2BiC13. Subsequently 3RbC1,2BiCI3 gives BiCI? and RbCI.

191

192

Elements of Group I

41

common anion.173Potential-energy-surface calculations for the M2X' ions show that the ion has substantial binding energy (ca. 1.5-2 eV with respect to M'+MX), where M and X are alkali metal and halogen, respectively. The most stable configuration varies from linear for (heavy M, light X) to strongly bent for (light M, heavy X).*" The hydrolysis of the halides of lithium, sodium, beryllium, and magnesium, amongst others, has been rationalized in terms of Lewis acid-base properties. 175 The crystal structures of the compounds KICl, and KIC1,,H20 have been determined from X-ray diffraction data. Potassium dichloroiodide crystallized in space group P2,/c, with a = 8.507, b = 10.907, c = 12.126 A, p = 107.82", and Z = 8. The monohydrate crystallized in space group P2,/m, with a = 8.022, b = 9.611, c = 4.354 A, p = 97.03", and Z = 2. In the anhydrous compound the two independent ICl; ions are nearly linear and symmetric, with average I-Cl bond lengths of 2.55 A. The ICl; ion is also linear in the hydrate, with the same I-Cl bond 1e11gth.l'~ Crystals of KIBr,,H,O are orthorhombic, space group Pnnm, with a = 12.183, b = 13.046, c = 4.390 A, and Z = 4. The two independent IBr; ions are linear and symmetrical, both with I-Br bond The crystal structure of caesium dichloroiodide has lengths of 2.71 been refined as trigonal, space group Rgm, with a = 5.469 A, a = 70.67", and Z = 1. The I-CI bond length is 2.548 The hygroscopicity of the powdered salts NaCl, KBr, and KI prepared by recrystallization from ethanol has been studied by comparing the surface conductivity of the salts with their water adsorption isotherms. The surface conductivity-relative pressure relationships showed four parts. Adsorbed H 2 0 molecules forming <2 layers were physically adsorbed and those forming >2 layers dissolved salt particles and began to form hydrated ions possessing considerable mobility. For NaCl, KBr, and KI, the vapour pressures at which the adsorbed water molecules started to form the hydrated ions at 30°C were 33, 36, and 27% relative humidity, respectively. The ions were hydrated with 10, 11, and 9 molecules of water, re~pectively.'~~ A very large number of complex halides containing alkali-metal ions have been investigated. Many of these are covered in the section on Molten Halides. The majority of the remainder are presented in Table 5.180-1y2 173 174

175 176

177 17'

' 7 1

'* lE3

N. L. Yarym-Agaev and V. G. Matvienko, Teplofiz. Vys. Temp., 1973, 11, 757. S. M. Lin, J. G. Wharton, and R. Grice, Mol. Phys., 1973, 26, 317. P. W. Wiggans, Educ. in Chern., 1973,10, 178. S. Soled and G. B. Carpenter, Acta Cryst., 1973, B29, 2104. S. Soled and G. B. Carpenter, Acta Cryst., 1973, B29, 2556. F. Van Boihuis and P. A . Tucker, Acta Cryst., 1973, B29, 2613. T. Kanazawa, M. Chikazawa, M. Kaiho, and T. Fujimaki, Nippon Kagaku Kaishi, 1973, 1669. D. Babel, R. Haegele, G. Pausewang, and F. Wall, Materials Res. Bull., 1973, 8, 1371. S. D. Arthur, R. A. Jacob, and R. J. Lagow, J. lnorg. Nuclear Chem., 1973, 35, 3435. E. N. Kolosov, V. B. Shol'ts, V. A . Davydov, and L. N. Sidorov, Vestnik. Moskou. Uniu., Khim., 1973, 14, 315. V. I. Mikheeva, S. M. Arkhipov, and A. E. Pruntsev, Izuest. Akad. Nauk S.S.S.R., Ser. khim., 1973, 2810.

42

Inorganic Chemistry of the Main-group Elements

8 Lithium Compounds The chemistry of the typical elements has been re~iewed.”~A second review covers the alkali metals and alkaline-earth elements 0n1y.I’~ Tables of electronic wavefunctions have been compiled for the diatomic hydrides AH, where A denotes the elements Li through F, and Na through Cl.”’ X-Ray diffraction patterns at high pressure show that LiH retains the low-pressure NaCl structure up to 12.0 GPa (120 kbar).”‘ The preparation of the first stable complex metal hydride of copper, lithium dihydrocuprate(I), is reported from the reduction of LiCuMe, by lithium aluminium hydride in ether at low temperatures. The solid compound, LiCuH,, is solvated by ether and stable under ambient conditions for several The reduction of inorganic compounds with alkali-metal borohydrides has been reviewed together with the electrochemical properties of borohydrides in s ~ l u t i o n . ”The ~ crystal structure of lithium hydrazinium fluoroberyllate, Li(N,H,)BeF,, is orthorhombic, space group Pna2,, with a = 9.811, b = 8.880, c = 5.139 A, and 2 = 4. The Li and Be atoms are at the centres of corner-sharing F tetrahedra. The hydrazinium ions lie in channels in the resultant framework. Average Li-F and Be-F bond distances are 1.853 and 1.546,8,, respectively.”’ The Li,O-B,O, phase diagram has been reported. The monoclinic (aand p-) and the tetragonal y-forms of LiB02, and the two forms of Li6B409,have been studied by X-ray crystallography. The tetragonal (y -) form was formed by heating the monoclinic (a-)form at 350 “C for 30 h; the y-LiBO, was stable to 580°C. The lattice constants of tetragonal y-LiBO, are a = 4.196, c = 6.51 1 A, space group I a 2 d . Monoclinic pLiBO, (metastable, m.p. 822 “C) was prepared from y-LiBO, at 580 “C by enantiotropic transformation. The compound Li6B409,previously prepared, lS4

N. A. Zhegul’skaya and L. N. Sidorov, Zhur. fiz. Khim., 1973, 47, 1622.

A. G . Dudareva, T. V. Fedorova, Yu. E. Bogatov, and P. I. Fedorov, Zhur. neorg. Khim., 1974, 19, 1607. D . E. Scaife, P. F. Weller, and W. G. Fisher, J. Solid State Chem., 1974, 9, 308. T. B. Brill, R. C. Gearhart, and W. A. Welsh, J . Magn. Resonance, 1974, 13, 27. lS8 K. 1. Petrov, V. V. Fomichev, G . V. Zimina, and V. E. Plyushchev, Khim. Khim. Tekhnol., Tr. Yubileinoi Konf., Posvyashch. 70-Letiyu Inst., ed. A. N. Bashkirov, (Mosk. Inst. Tonkoi Khim. Tekhnol.), 1970, (Publ. 1972), p. 349. 189 K. Kihara and T. Sudo, Acta Cryst., 1974, B30, 1088. S. H. Lee and C. A. Wulff, J. Chem. Thermodynamics, 1974, 6, 85. 191 V. D. Shcheglova, V. P. Gofman, S. B. Stepina, and V. E. Plyushchev, Izuest. sibirsk. Otdel. Akad. Nauk S . S . S . R . , Ser. khim. Nauk, 1973, 75. 192 V. D. Shcheglova, S. B. Stepina, V. E. Plyushchev, and A. S. Berger, Izuest. sibirsk. Otdel. Akad. Nauk S.S.S.R., Ser. khim. Nauk, 1973, 78. D. W. A. Sharp, M. G. H. Wallbridge, and J. H. Holloway, Annual Reports ( A ) , 1973, 69, 175. 194 M. F. Steffel, Ann. Reports Inorg. Gen. Synth., 1973, 1, 1. 1 9 5 P. E. Cade and W. Huo, Atomic Data Nuclear Data Tables, 1973, 12, 415. 196 B. Olinger and P. M. Halleck, Appl. Phvs. Letters, 1974, 24, 536. I y 7 E. C. Ashby, T. F. Korenowski, and R . D . Schwartz, J.C.S. Chern. Cornm., 1974, 157. J . Hanzlik, Chem. listy, 1973. 67, 1239. 19’ M. R. Anderson, I . D. Brown, and S. Vilmino, Actu Cryst.. 1973. B29, 2625. lS5

lS6

43 is dimorphic. At 650 "C, p -Li6B,0,Sy-Li,B,09.200 Lithium peroxoborate monohydrate, LiBO,,H,O, decomposes under vacuum at 115-145 "C, but only half the oxygen and water are lost. The residue has the composition LiB0,.,,0.5Hz0, and complete loss of water occurs at 250-300 "C. The activation energy for the decomposition of the peroxoanion is 46 kcal mol-l. The suggested structure for LiBO,,H,O is as shown in (13)."' Lithium alu-

Elements of Group I

minoborate, Li,Al,(BO,),, is monoclinic, space group P1, with a = 6.13, b = 4.82, c = 8.23 A, p = 118", and d(ca1c) = 1.58 for 2 = 1. The structure is composed of infinite chains of [A1,(B03),]6- and layers of Li' tetrahedra.," The melting and dissociation of lithium carbonate have been studied by differential thermogravimetry (t.g.a.) and differential thermal analysis (d.t.a.). Thermal dissociation of Li2C0, to Li,O and CO, begins at 200°C. An endothermic effect with the maximum at 745 "C corresponds both to the melting and the thermal dissociation. The course of the process is strongly influenced by the ease with which CO, is released from the sample; the peaks at 745 "C on the t.g.a. and d.t.a. curves are only coincident when one works with thin layers of sample.2o3In other work the m.p. of Li,CO, is given as 733"C, and up to this temperature the structure of the solid is monoclinic. Sodium and potassium carbonates possess three crystal forms: ordered monoclinic

hexagonal (high temperature)

K,34y Na347g21.c disordered monoclinic

The data confirm previous conclusions that two regions of continuous solid solution exist between Na2C03and K,C03. There is also evidence that in the binary Li2C03-Na2C03,an intermediate compound LiNaCO, Polymorphism also exists in the Li,X04 (X = Si, Ge, or Te) compounds. All three phases are isostructural above 700-750 "C but undergo phase transformations on cooling. Only Li,GeO, and Li,TeO, are isostructural at lower 'O0 '01

' 0 2 ' 0 3

'04

C. Maraine-Giroux, R. Bouaziz, and G. Perez, Rev. Chirn. rnine'rale, 1972, 9, 779. M. S. Dobrolyubova and A . B. Tsentsiper, Izvest. Akad. Nauk S.S.S.R., Ser. khirn., 1974, 1218. G. K. Abdullaev and Kh. S. Mamedov, Kristallografiya, 1974, 19, 165. T. E. Machaladze, G. D. Chachanidze, and R. N. Pirtskhalava, Soobshch. Akad. Nauk Gruz. S.S.R., 1973, 71, 109. G. Papin, Compt. rend., 1973, 277, B, 691.

44

Inorganic Chemistry of the Main -group Elements

temperature^.^^^ The mixed alkali-metal tetragermanate LiNaGe409crystal~ , a = 15.90, b = 4.683, c = 9.322 A, and lizes in the space group P c ~ 2with 2 = 4. A substitution of Na by Li leads to an isomorphous series LiNa-+ LizGe409.zo6 Ge409-+ Lil,,N~.,Ge409 X-Ray photoelectron spectroscopy of the N( 1s) core-electron binding energies of azides containing the alkali metals indicates that the electronic structure of the Ng ion is largely unchanged from compound to compound, and the differing thermal stabilities cannot be explained on the basis of different electronic structure. The N(1s) spectrum consists of two peaks in the vicinity of 398.5-404.9 eV separated by ca. 4.4 eV, as shown in the upper part of Table 6. The peak for terminal N is slightly broader than that Table 6 N(1s) Binding energies for metal azides

B.E./eV h

B.E. DiferenceleV

r403.4 402.6 404.9 404.0 403.9 403.6 403.6 403.9

399.8 398.5 400.6 399.6 399.6 399.4 399.2 399.8

4.4 4.1 4.3 4.4 4.3 4.2 4.4 4.1

403.3 403.1 403.1 402.6 402.4

398.9 398.7 398.7 398.3 398.1

4.4 4.4 4.4 4.3 4.3

of the central N. The values for the pure alkali-metal azides in the lower part of the table have been reported previously, and are included for compari~on.~~' The i.r. spectra of LiN0, and KNO, ion pairs matrix-isolated in argon, glassy water, and glassy ammonia at 1 2 K have been measured and show a drastic reduction in the splitting of the v3(NO;) asymmetric stretch in the H,O and NH, matrices when compared to the argon base. This effect is attributed to solvation of the alkali-metal cation of the contact ion pairs, which occurs through the lone pairs of electrons on N or 0 of the matrix The d.t.a. of Li,P,09,3H,0 showed that dehydration occurred at 130-150 "C, and at higher temperatures infinite chains of tetrahedra were formed. The phosphate Li4P40,,,6H,0, prepared by addition of P,O, to aqueous Li,CO, at 0°C and evaporation at <40"C, crystallized in the monoclinic space groups Cc or C2/c, with a = 17.108, '06

'07 '08

B. L. Dubey and A. R. West, J. Inorg. Nuclear Chem., 1973, 35, 3713. R. G. Matveeva, V. V. Ilyukhin, and N. V. Belov, Doklady Akad. Nuuk S.S.S.R., 1973, 213, 584. H. P. Fritzer, D. T. Clark, and I. S. Woolsey, Inorg. Nuclear Chem. Letters, 1974, 10, 247. N. Smyrl and J. P. Devin, J. Phys. Chem., 1973, 77, 3067.

Elements of Group I

45

b = 16.994, c = 13.541 A, p = 127.52", and 2 = 8. It was dehydrated to Li4P4012,4HzO at 70 "C and to amorphous Li4P4012at 170 "C. Transformation to crystalline LiP03 occurred at 350 "C. The polyphosphate (LiPO,), crystallized in the monoclinic space group Pn or P2/n, with a = 16.490, b = 5.427, c = 13.120 A, p = 98.89", and Z = 20.'09 Lithium trimetaphosphate hydrate, Li3P3O9,3H,O,prepared by the reaction of Ag3P309with a neutral solution of LiCl, crystallizes in the hexagonal-rhombohedra1 space group R,,with a = 12.522, c=5.594& and Z = 3 . The three-fold axis determines the symmetry of the [P3O9I3-ring and the Li atom is tetrahedrally co-ordinated.210 The vaporization of lithium metaphosphate has been investigated by mass spectrometry. The standard enthalpy and entropy of LiP03 sublimation are 80.0 kcal mo1-I and 41.2 e.u., respectively. The standard enthalpy and entropy of the LiP03 vapour are 221.9 kcal mol-' and 58.5 e.u., respectively.'.'.' A new binary lithium antimonide, Li2Sb, has been reported. The compound is prepared from metallic antimony and Li3N by slowly increasing the temperature from 100 to 430°C. Although stable to lOOO"C, Li,Sb begins to decompose at 1200°C to the elements.212 The compound 2LiOH,KOH has been prepared by the reaction of the stoicheiometric proportions of the component hydroxides in a melt at 360 "C for 3h under an inert atmosphere. X-Ray diffraction measurements indicate that single crystals of the compound are monoclinic, with a = 6.134, b = 8.10, c = 5.197 A, y = 103" 12', 2 = 2, d(X-ray) = 1.88, and d(expt) = 1.85.2'3The crystal structure of lithium hydroxylammonium sulphate has been determined as orthorhombic, space group Pbca, with a = 18.461, b = 267, c = 6.695 A, and Z = 8. LiNH,OHSO, contains sheets of LBO4 which are hydrogen-bonded together by the NH,OH' ions. The The standard lithium ion is surrounded by four oxygen atoms at 1.96 A.214 enthalpy of formation, AH", has been calculated as -101.8 kcal mol-' for lithium monoselenide Li2Se from measurement of the heat change, measured in a bomb calorimeter, accompanying the rea~tion:~" Li,Se (s) + 4F, (g) + 2LiF (s) + SeF, (s) The crystal structures of the alkali-metal tellurites M,Te03 (M = Li, Na, K, Rb, or Cs) have been studied by X-ray diffraction. All the compounds are monoclinic; K,Te03 crystallizes with a = 10.86, b = 6.29, c = 7.22 A, 2 = 4, d(ca1c) = 3.40, d(expt) = 3.35, and the compounds Rb2Te03and Cs,TeO, are isotypic with the potassium salt.216 '09 210

'12 '13

'14 '15

216

J. C. Grenier and A. Durif, Z. Krist., 1973, 137, 10.

R. Masse, J. C. Grenier, G. Bassi, and I. Tordjman, Z. Krist., 1973, 137, 17. I. A. Rat'kovskii, L. Ya. Kris'ko, B. A. Butylin, and G. I. Novikov, Doklady Akad. Nauk 1974, 18, 435. Belorussk. S.S.R., R. Gerardin and J. Aubry, Compt. rend., 1974, 278, C, 1097. L. S. Itkina, N. V. Rannev, S. M. Portnova, and T. A. Demidova, Zhur. neorg. Khim., 1974, 19, 1422. S. Vilminot, M. R. Anderson, and I. D. Brown, Acta Cryst., 1973, B29, 2628. M. Ader, J. Chem. Thermodynamics, 1974, 6, 587. H. F. Thuemmel and R. Hoppe, 2. Naturforsch., 1974, 29b, 28.

46

Inorganic Chemistry of the Main -group Elements

Vibrational spectra of matrix-isolated alkali-metal chlorate ion pairs have been obtained for MClO, (M = Li, Na, or K) monomers in Xe and Ar. The LiClO, sample showed bands due to O,, Cl,, and C10, formed by decomposition during sample preparation, but the other molecules did not decompose. (MCIO,), dimer bands appeared in all spectra but disappeared on dilution for both NaCIO, and LiClO,. Force constants and bending- and stretching-mode assignments are given.217Bis(fluorosulphato)bromates(I) of lithium and sodium have been prepared from solutions of MS0,F in BrS0,F. After removal of solvent at ambient temperature by vacuum, the products Li [Br(SO,F),] and Na [Br(SO,F),] were isolated. The compounds were homogeneous and had Raman spectra similar to that of Cs [Br(S0,F),].”8 High-purity lithium perxenonate, Li4Xe06,2H,0, has been prepared by the addition of aqueous Na4Xe06to an aqueous LiOH-Li,SO, solution followed by treatment with an oxygen-ozone mixture. Alternatively, the compound is produced by the reaction of Na4Xe06with aqueous Li,S04. The kinetics of the thermal decomposition of the compound have been determined. The activation energy for the process is 55.7 kcal mol-’. At 40-120 “C, Li,Xe06,2H20 loses two H,O molecules, and it decomposes to Li,O, Xe, and 0, at 294-300”C.2’9

9 Sodium Compounds Gmelin’s Handbook of Inorganic Chemistry, System No. 2 1, Index Volume on Sodium, has been published.”” The reaction of sodium with hydrogen has been studied between 260 and 357°C at pressures between 14 and 49 atmospheres. Three stages can be distinguished in the reaction. At a given temperature, consumption of sodium is slow due to hydrogen dissolving in the liquid metal. Subsequently, the saturated metal reacts more rapidly with the gas to form a nonstoicheiometric metal-rich hydride. Finally, the rate falls off exponentially as the non-stoicheiometric hydride is converted into stoicheiometric NaH.”l Addition of carbon monoxide to the hydrogen was found to influence both the rate of formation of NaH and the mechanism. The same effect was brought about by sodium isobutylate and sodium isobutyrate, and carbon monoxide is considered a precursor of these catalysts. The fact that the catalysts act chemically and that the individual reactions are of second order with respect to sodium and of first order with respect to hydrogen supports 217

’18

220

221

N. Smyrl and J. P. Devlin, J. Chem. Phys., 1974, 60, 2540. W. M. Johnson and G. H. Cady, Inorg. Chem., 1973, 12, 2481. N. N. Alainikov, V. K. Isupov, and I. S. Kirin, Izuest. Akad. Nauk S.S.S.R., Ser. khim., 1974, 278. Gmelin’s Handbook of Inorganic Chemistry, System No. 21: Sodium. Index Volume, 8th edn., 1973. V. Prochazka and M. Nedved, Coll. Czech. Chem. Comrn., 1973, 38, 2845.

47

Elements of Group I the previously reported scheme: R'R2CHCH20Na+ Na R'R'CNaCH,ONa

-+

R'R2CNaCH,0Na + NaH

+ H, + R'R"CHCH,ONa + NaH

The reaction of the catalyst with sodium occurs first, and the catalyst is regenerated by the action of hydrogen and sodium hydride is produced.222 The crystal structures of sodium borate, Na20,2B203,and a-sodium triborate, Na,0,3B,03, have been determined from three-dimensional Xray data. Na,0,2B20, is triclinic, space group P i , a=6.5445, b=8.602, c = 4855 A, a = 93.279", p = 94.870", y = 90.843", with d(ca1c) = 2.272 for 2 = 4. a-Na,0,3Bz0, is monoclinic, space group P2,/c, a = 10.085, b = 11.363, c = 10.845 A, p = 104.48", and d(ca1c) = 2.242 for 2 = 6. In the first salt the anion borate polymer forms layers composed of dipentaborate groups and triborate groups, with one non-bridging oxygen atom. This is a novel feature in diborates. The Na atoms are co-ordinated by six or seven oxygen atoms at distances ranging from 2.260 to 2.872 In the second salt the borate anion forms two separate and interpenetrating infinite frameworks, each consisting of pentaborate and diborate groups in equal amounts. The three crystallographically different Na atoms are co-ordinated by five, six, and six oxygen atoms, respectively, at distances between 2.280 and 2.742 8,."' A neutron powder-diff raction study of disodium acetylide, Na2G, confirms that the structure is monoclinic, space group D~~-14,/acd, and the unit cell, a = 6.743, c = 12.674 A, holds eight Na,C2 units. The Na' and CZ- ions are arranged in a distorted anti-CaF,-type packing, with Cz replacing Ca. The Ci- array exhibits a spiral configuration, having a turn angle of 90". This spiral array of linearly dispersed negative ions causes similar helical 1 anti-CaF, positions. The - e C O f ' Elements of Group I lllJ,gnificantly different from 1.204 8, in bond distance is 1 . L W w n, wlllLll C,H, and 1.191 A in CaC, but which is shorter than the 1.27 8, in sodium hydrogen acetylide, NaHC2. Each Na' ion is surrounded by six carbon atoms, two each at 2.623, 2.648, and 2.774 A, giving a close packing of Ciions round Na'. The nearest non-bonding C-C distances are long at 4.050-4.255 A, however, giving loose packing among Ci- ions and an unusually low crystal density of 1.614 g C M - ~ . " ~ The relative reducing properties of metal carbides towards diphenylchlorophosphine, Ph,PCl, have been assessed. Earlier it was shown that CaC, reacts with Ph,PC1 to form tetraphenyldiphosphine and carbon according to: 2Ph,PCl + CaC,

+ Ph,PPPh,

+ CaCl, + 2C

V. Prochazka and M. Nedved, Coll. Czech. Chem. Comm., 1973, 38, 2850. J. Krogh-Moe, Acta Cryst., 1974, B30, 578. J. Krogh-Moe, Acta Cryst., 1974, B30, 747. '"M. Atoji, J. Chem. Phys., 1974, 60, 3324. 222

223

224

48

Inorganic Chemistry of the Main -group Elements

It is now established that Na2C2and MC, (M = Sr or Ba) also react in this way, and it appears that to do so the carbide must have both ionic character and .rr-electron density equivalent to a C=C bond.226The vaporization of Na2C0, has been studied by mass spectrometry. Decomposition starts above 600°C. At 800"C, intense liberation of CO, occurs, and Na' ions appear in the vapours as a result of the decomposition of Na,O with an enthalpy change of 51 kcal mol-'. Ionization potentials of 13.92 and 5.55 eV were also obtained for CO, and Na, respectively.227The lattice parameters a, b, and c, respectively, of the orthorhombic compounds Na4XSlo ( Z = 4 , space group Cmcm) are: X=Si, 12.681, 12.720, 10.346 A; X = Ge, 12.847, 12.901, 10.476 A. The crystallographic parameters of cubic BazGe,SIowith space group Fd3m or Fd3 are a = 14.899 A, d(expt) = 3.48, and d(ca1c) = 3.55 for Z = 8. The compounds are made up of sodium or barium cations and [XS,,]"-cage-type anions, which are the result of condensation of four XS, tetrahedra each sharing three of its vertices (S atoms) with other tetrahedra."' Na,Ge,S,, and Na,GeS, were discovered by d.t.a. of Na,S-GeS, mixtures. Na,GeS, contains polythiogermanate [(GeS,),]""- ions.229Three ternary oxides of lead containing sodium ions have been investigated. These are Na6Pb0,, Na,PbO,, and NasPbO,. The first two compounds are orthorhombic, space group Pbcn, with lattice parameters a = 10.68, 16.83; b = 5.71, 6.94, c = 10.99, 5.88 A, Z = 4, 8, respectively. In Na6Pb0, there are isolated PbO, pseudotetragonal pyramids in which Pb4+ is four-co-ordinate. The sodium ion occupies vacancies between oxygen atoms, and the three crystallographically differNa,PbO, has a ent cations have co-ordination 4, 5, and 5, layer lattice bridged by Na' ions,231and Na6Pb0, has an ordered variation of the Na,O structure. Na6Pb0, is cubic, with space group I43m and a = 11.01 A, Z = 8.232 A mass spectrometric study of the vaporization of sodium metaphosphate, NaPO,, shows that the vapour is composed of monomeric NaP0, and dimeric (NaPO,), molecules. At 1043-1344 K the enthalpies of vaporization of NaPO, and (NaPO,), are 68.8 and 79.7 kcal mol-', respectively. The mass spectrum contains peaks due to NaPO:, Na,PO:, NaPO:, NaPO', Na+, PO;, PO;, and PO'."33 The compounds NaSbO,, Na,Sb407, and NaSb,O,,H,O have been prepared from Sb,O, in the presence of NaOH 226

J. D. Bogden, J. Inorg. Nuclear Chem., 1973, 35, 3950. G. A. Semenov, A. D. Volkov, and K. E. Frantseva, Trudy Leningrad. Tekhnol. Inst. Tsellyul.-Bum. Prom., 1973, 30, 153. 228 M. Ribes, J. Olivier-Fourcade, E. Philipott, and M. Maurin, J. Solid State Chem., 1973, 8, 195. '" J. Olivier-Fourcade, E. Philippot, M. Ribes, and M. Maurin, Rev. Chim. mine'rale, 1972, 9, 757. 2 3 0 P. Panek and R. Hoppe, Z. anorg. Chem., 1973, 400, 208. 231 P. Panek and R. Hoppe, Z. anorg. Chem., 1973, 400, 219. 232 P. Panek and R. Hoppe, Z. anorg. Chem., 1973, 400, 229. 233 A. V. Steblevskii, A. S. Alikhanyan, I. D. Soholova, and V. 1. Gorgoraki, Zhur. neorg. Khim., 1974, 19, 1450. 227

Elements of Group I

49

under hydrothermal conditions. NazSb40, crystallizes in the space group C,/c or Cc, with a = 11.030, b = 16.920, c = 9 . 6 4 5 & and p = 149.4". NaSbO, is not isotypic with compounds of the type NaM"'O,, where MI1'= Fe, Cr, Al, or Ga.234 Different crystalline varieties of sodium hydroxide are reported. Phase transformations in this compound are: orthothombic a-NaOH

245 "C

monoclinic p-NaOH

291 "C

cubic y-NaOH

y-NaOH was observed up to the melting point of 321 0C.'35The partial phase diagram of the Na-NaOH-NaH-H system has been Cryoscopic measurements on solutions of alkali-metal polysulphides in fused potassium thiocyanate show that the freezing point of the solvent is depressed by Na,S by an amount corresponding to three particles. These are believed to be 2Na' and CN-, the cyanide ion being formed by the reaction of S2with the solvent. NaZS4.4and KZS5.9 give opaque solutions in KSCN which are initially dark blue green, and which slowly lose S vapour and change colour to pale yellow. Initially the f.p. depression corresponds to 4 and 2 foreign particles, respectively, but when sulphur evolution is complete, the Sodium reacts in final depressions indicate 2 and zero foreign liquid ammonia with simple alkyl sulphides to cleave the sulphur-carbon bond according to: RSR + 2Na + NH,

+ NaSR

+ RH + NaNH,

where R is an alkyl group. Reactions with Me,S, Et,S, Pr2S, and EtMeS are first-order with respect to each reactant but second-order overall. Secondorder rate constants at -33.9 "C are 5.54, 8.50 x lo-", 2.95 x lo-', and 2.26 1mol-' s-' for the above sulphides, respectively, with corresponding activaLon energies 3.8, 9.3, 11.6, and 3.1 kcal m ~ l - ' . "Sodium ~~ dithionate has been shown to decompose non-oxidatively when heated. Decomposition occurs by two routes, depending on the bulk sample configuration. Heating a heaped sample at 16°C min-' promoted the reaction: 2Na,Sz04 +. Na,S,O,

+ Na,S03 + SO,

at 205 "C with the evolution of 47 kJ mol-'. Heating a thin layer, however, evolved 63 kJ mol-' at 210°C, with the formation of Na,S203, Na2S306, Na,S04, and Na,S03.z39The reaction of Na2S,03 with As2S3and As2S5 proceeds through the decomposition of sodium thiosulphate, with the 234 235

236

237 238

239

C. Giroux-Maraine, P. Maraine, and R. Bouaziz, Cornpt. rend., 1974, 278, C, 705. G. Papin and R. Bouaziz, Cornpt. rend., 1973, 277, C, 771. B. A. Shikhov, V. G. Karpenko, G. D. Chub, and N . M. Taran, Zhur. priklad. Khim., 1974, 47, 514. B. Cleaver and A. J. Davies, Electrochim. Acta, 1973, 18, 741. R. L. Jones and R. R. Dewald, J. Amer. Chem. Soc., 1974, 96, 2315. K. Goodhead, I. K. O'Neill, and-D. F. Wardleworth, J . Appl. Chem. Biotechnol., 1974, 24, 71.

50

Inorganic Chemistry of the Main-group Elements formation of Na3AsS,, whereas with Na2S04the compounds Na2S0,, As203, and SO, are formed. At 325-48OoC, Na,S203 undergoes a polymorphic transformation and decomposes to a polysulphide and ~ u l p h a t e . ~The ~' enthalpy of formation, AH&, of sodium hydrogen selenate NaHSeO, has been calculated as -201.3 kcal mol-1 from calorimetric measurements of the enthalpy (ca. 6.55 kcal mol-') of the reaction: NaHSe04+ BaC1, + BaSeO, + NaCl+ HCl and the enthalpy (-1.936 kcal mol-') of solution of crystalline NaHSeO, in water.241Sodium selenatoindates have been reported from reactions of Na2Se04with In,SeO, in aqueous solutions at 20°C. The compounds Na3In(Se04),,7H,0 and NaIn(Se04)2,6H20were characterized by thermal analysis and X-ray diffraction methods. The former compound dehydrates at 70-150"C7 and both compounds decompose at 620°C to In,03 and Na,SeO,. The second compound is completely dehydrated at 160 0C.24' Sodium selenite decomposes through fusion according to:243 4Na2Se0, = 4Na20,3Se0,+ SeO, The synthesis and characterization by X-ray powder diffraction, and the Raman and i.r. spectroscopy, of the compounds M,TeOF4 and M,Te0,F2 (M = alkali metal) have been described. M2TeOF4 is isomorphous with M,SbF,, and the unit cells are nearly identical, indicating that the anion volumes are very similar. The spectra are consistent with a C4u[TeOF,]'ion and a CZv[TeO2F2I2-ion, with oxygen in equatorial positions."" The i.r. spectrum of matrix-isolated alkali-metal chlorite ion pairs has been obtained at 15 K. Alkali-metal atoms and C10, at high dilution in argon were deposited on to an optical surface. Intense i.r. absorptions near 820, 790, and 420 cm-', which exhibited small alkali-metal effects, were attributed to the three intra-ionic modes of the C10; anion in the M'C10; species. The C1-0 force constant for C10; (4.11 mdyn A-') is less than the which is consistent with the antibonding value for C102 (6.61 mdyn k'), character of the additional electron on ClO;.'"' The formation of the polyiodides of the alkali metals and alkaline-earth metals MI3, MI,, M'(I&, and M'(IJ,, where M = Na, K, Rb, or Cs and M' = Ca, Sr, or Ba, has been reported; they were made by allowing iodine to react with the metal iodide in DMS0.'46

242

M. I. Zhambekov, S. M. Isabaev, and H. N . Polukarov. Trudy Khim.-Met. Inst., Akad. Nauk Kazakh. S.S.R., 1973, 23, 24. L. G. Sobol and N. M. Selivanova, Izvest. V.U.Z.,Khim. i khim. Tekhnol., 1973, 16, 1493. E. N. Deichman, 1. V. Tananaev, and N. V. Kadoshnikova, Zhur. neorg. Khim., 1973, 18,

243

2085. V. G. Shkodin and V. P. Malyshev, Trudy Khim.-Met. Inst., Akad. Nauk Kazakh. S.S.R.,

240

241

244

245 246

1973, 23, 29. J. B. Milne and D . Moffett, Inorg. Chew., 1973, 12, 2240. D . E. Tevault, F. K. Chi, and L. Andrews, J . Mol. Spectroscopy, 1974, 51, 450. E. Ya. Gorenbein, T. D. Zaika, E. P. Skorobogat'ko, and V. L. Pivnutel, Zhur. obshchei Khim., 1974, 44, 1422.

Elements of Group I

51

10 Potassium Compounds The complex hydrides of approximate compositions K,Cu3H,,xNH3 and CsCuH2,xNH3have been prepared by the reaction of hydrogen with a mixture of KNH, or CsNH2 with CuI in liquid ammonia. These ternary hydrides are orange-red and thermally unstable. Characterization was by elemental analysis, X-ray powder diffractometry, and, in the case of the potassium compound, by Raman spectroscopy and magnetic m e a ~ u r e r n e n t s . ~ ~ ~ A new ternary oxide containing potassium and magnesium, &Mg04, has been prepared by the reaction of K,O with MgO at 800°C. X-Ray diffraction data from a single crystal show that the compound is hexagonal, with possible space groups P63mc, P62c, or P63/mm~,and lattice parameters a = 8.478 and c = 6.585 A.248 The thermal decomposition of the alkali-metal perchloratoborates M(BCIO,), ( M = K, Rb, or Cs) is endothermic under vacuum, and the gaseous products are Cl,O,, ClO,, C12, and 0,. The residue is a mixture of MClO, and &O,. The exothermal nature of the decomposition of Cs B(C10,), at atmospheric pressure is explained by the decomposition of Cl,0,.24’ The lattice energies, U,, of the compounds MBH,,, M’(BH,,)2, MAlH,, and M’(AlH,), (M = Group I metal, M’= Group I1 metal) have been calculated from the Kapustinskii equation. The values were used to determine the radii of the anions BH;; and AlH; as 2.3 and 2.85& respectively. The standard enthalpies of formation of these ions are -23 and -39 kcal mol-’, respectively, and the reaction of AlH, with H- to produce AlHi evolves 71 kcal mol-’. The enthalpy of formation of rubidium aluminium hydride was calculated from the relationship AH(RbA1K) = UL (RbAlH,) + AH(Rb+)+ AH(A1H;) = -43 kcal mol-’. The lattice energies for the borohydrides and aluminohydrides as derived from this type of equation are collected in Table 7.2’0A new potassium aluminate, K3A103,is reported to crystallize from the K,O-KAlO, system. The compound has space group C/m, with a = 6.97, b = 11.01, c = 6.45 A, and p = 102”30’. The crystal structure is isotypic with that of K6Fe20,,.2s1 Molten alkali metals react with Table 7 Lattice energies of borohydrides a nd a lum inohyd~des UJ

Compound

LiBK NaBH, KBH, RbBH, CsBH, 247

248 249

250 251

kcal mol-’ 186 168 154 150 149

Compound

LiAlH, NaAlH, KAlH, RbAlH, CsAlH,

VL! kcal mol-’ 153 134 123 121 110

K. A. Strom and W. L. Jolly, J . Inorg. Nuclear Chem., 1973, 35, 3445. J. C. Bardin, M. Avallet, and M. Cassou, Compt. rend., 1974, 278, C, 709. V. P. Babaeva and V. Ya. Rosolovskf, Izvest. Akad. Nauk S.S.S.R., Ser. khim., 1974, 507. T. N. Dymova, Izuest. Akad. Nuuk S.S.S.R., Ser. khim., 1973, 2661. A. Bon, C. Gleitzer, A. Courtois, and J. Protas, Compt. rend., 1974, 278, C, 785.

52

Inorganic Chemistry of the Main-group Elements

solid aluminium in the presence of hydrogen gas under 100-400 atmospheres at 2 0 0 4 0 0 “C to form liquid MAlH, (M = Na, K, Rb, or Cs). The lithium compound was not obtained, perhaps due to the greater stability of LiH.”, The partial hydrogenation of the phase KC, results in KC,H,,,. Insertion of alkali metals into the free spaces in this phase produces new phases K,C,H,,,,MC, (M = K, Rb, or CS).’~,The solvate K,CS4,MeOH crystallizes from K,CS, in methanol. This solvate is remarkably stable to heat considering the thermal instability of unsolvated K,CS,. Potassium thioperoxycarbonate hemihydrate K,CS4,0.5H,0 was formed in a displacement reaction of K2CS4,MeOH with water vapour. The salts were characterized by comparing their i.r. spectra with that of K,CS,.2s4 The effect of the type of alkali-metal and alkaline-earth-metal cation on chemical bonding in germanate compounds has been critically reviewed. Discussion includes the i.r. spectra of the germanates of K, Na, Li, Ba, Ca, bond strength and degree of and Mg with reference to the Ge-0 ionic/covalent b ~ n d i n g . ” Potassium ~ octagermanate, K,Ge,OI7, is orthorhombic, space group Pnarn-D:;, with a = 13.37, b = 13.37, and c = 8.85 A.256 Potassium aluminium pyrophosphate, KAlP,O,, is monoclinic, space group P21/c, with a = 7.308, b = 9.662, c = 8.025 A, p = 106.69”, and 2 = 4. The [P207]4-anion consists of a pair of corner-sharing PO, groups in a nearly staggered configuration. The anions lie in planes parallel to (001). The A13+cations are bonded to six oxygen atoms contributed by anions in three layers of P , 0 7 groups. The potassium ion is co-ordinated to ten oxygen atoms lying within a spherical shell of inner and outer radii 2.739 and 3.185 A.25’ The solubility has been studied of potassium polysulphides and polyoxides in aprotic solvents. In these solvents, hydrogen-bonding between polyanion and solvent is eliminated, and therefore the chemical reactivity of the solute is higher than when in protic solvents. Bright green solutions are obtained when the potassium polysulphides K,S,, K,S,, KZS4, and K S , dissolve in DMSO, DMF, AcNMe,, or hexamethylphosphoramide; solutions in sulpholane are red-brown. The solubility of potassium peroxide K,O, is much lower than that of the sulphides, being 0.12--0.14%. The spectra of K,S,, KO,, and K,O, have been obtained in Me,SO; the polysulat 440-510 cm-l and K,O, has A,, at 880 ~rn-’.~”’ phide shows A,, T. N. Dymova, N. G. Eliseeva, S. I. Bakum, and Yu. M. Dergachev, Doklady A k a d . N a u k S . S . S . R . , 1974, 215, 1369. 2 5 3 P. Lagrange, A. Metrot, and A. Herold, Compt. rend., 1974, 278, C, 701. 2 5 4 M. Abrouk, Compt. rend., 1974, 278, C, 875. 2 5 5 V. V. Tatasov and P. A. Soboleva, Zhur. jiz. Khim., 1973, 47, 3063. 256 E. Fay, H. Vollenkle, and A. Mittmann, 2. Krist., 1973,138,439. ”’ H. N. Ng and C. Calvo, Canad. J. Chem., 1973, 51, 2613. ’’’ V. Brunere, B. Petersons, and Dz. Peica, Latv. P.S.R. Zinat. A k a d . Vestis, Kim. Ser., 1973, 401. 252

Elements of Group I

53

Enthalpies of formation of potassium polytellurites have been calculated from enthalpies of solution of the compounds in water as determined by calorimetry. The standard enihalpies of formation, AH298/kcalmol-', are: K,Te,05, -3 15.9; K2Te404,-467.2; K,Te409,4H,0, -754.6. The enthalpy of hydration of K2Te409,4H,0is - 14.78 kcal m01-l.'~~

11 Rubidium Compounds Rubidium dihydrogen orthophosphate, RbH2P04, has been studied by calorimetry. The enthalpies, AHl and AH,, of the reactions:

were determined as -78.4 and -179.0 kJ mol-', respectively. Using these values and the known enthalpies of formation of RbOH and H3P04,a value of -1570.3 kJ mol-1 was calculated for the enthalpy of formation, AH& of RbH2P04.Other standard enthalpies of formation calculated were Rb2H,P207,-2823.4 kJ mol-l, and RbP03, -1246.0 kJ mol-'. The enthalpy of the polymorphic transformation of RbH2P04(taking place at 110-120 "C), determined by calorimetric measurements as the difference in AHl values for RbH,PO, dried in vacuum at 135 and 65 "C, respectively, is 3.8 kJ mol-1.26" Crystals of P-Rb,S04 grown from a melt have been examined by X-ray diffractometry, and the results confirm the general features of the atomic arrangement reported previously. The compound is orthorhombic, space group Pnarn, with Q = 7.8128, b = 10.4255, c = 5.9694 A, and d(ca1c) = 3.647 for Z = 4 . The tetrahedral SO:- ions are regular, with an average S-0 distance of 1.474 A. The Rb' ions are surrounded by nine or eleven oxygen atoms.261D.t.a. of aqueous solutions of rubidium and caesium sulphates has revealed the existence of hydrates below 0°C. The Cs2S04H,O phase diagram suggests that, for caesium, the hydrate is Cs2S04,10H20.262 The phase diagram of the Rb2TeO3-TeO2system has been determined by d.t.a. Compounds Rb2Te409and Rb,Te,O, formed in the system melt congruently at 430 and 5 10 "C, respectively. RbzTe205forms two eutectics; with Rb2Te0, at 63.5 mole % TeO,, melting at 500"C, and with Rb,Te,O, at 78 mole % TeO,, melting at 412°C. Rb,Te,09 forms a eutectic with TeO, at 83 mole % TeO,, melting at 400"C.'63

2s9

260

261

262 263

V. I. Mazepova, K. K. Samplavskaya, and M. Karapet'yants, Zhur. fiz. Khim., 1973, 47, 2983. P. K. Rud'ko, V. N. Yaglov, and G. I. Novikov, Vestsi Akad. Nauuk Belarusk, S.S.R., Ser. khim. Nauuk, 1973, 111. A. G. Nord, Acta Cryst., 1974, B30, 1640. I. S. Rassonskaya and I. B. Kudinov, Zhur. neorg. Khim., 1973, 18, 2544. V. I. Mazepova, K. K. Samplavskaya, M. Kh. Karapet'yants, and A. E. Ivanova, Izuest. Akad. Nauk S.S.S.R., Neorg. Materialy, 1973, 9, 1001.

54

Inorganic Chemistry of the Main -group Elements

12 Caesium Compounds The crystal structure of caesium metaborate tetrahydrate, CsB02,4H20,is tetragonal, space group 14, with a=6.04, c =8.56A, and Z = 2 . The structure consists of isolated [B(OH),]- tetrahedra, which are connected by Cs' ions and hydrogen bonds. The Cs' ion is surrounded by eight oxygen atoms at distances 3.50 A.264Caesium triborate crystallizes in the orthorhombic space group P212121,with a = 6.213, b = 8.521, c = 9.170 A, and d(ca1c) = 3.357 for 2 = 2.""' Caesium trimethoxyfluoroborate, Cs[BF(OMe),], is prepared from CsF and B(OMe), in anhydrous methanol. The compound was characterized by n.m.r. and i.r. spectra, and it decomposes thermally to CsF and B(OMe), at 240-320 oC.266 The solubility of caesium tetrahydrogallate, CsGaH,, in diglyme decreases with increasing temperature, falling to zero at 120°C. The phase diagram of these mixtures shows the presence of the compound CsGaH4,4DG, incongruently melting at The caesium and rubidium -39.6"C with loss of two moles of digl~me."~ oxoindates and oxothallates, CszIn6010,Rb~In6O,o, Cs2Tl6OIo,and Rb,T16010,have been prepared by heating mixtures of the corresponding oxides in argon at 950-1000 "C for ten hours. The compounds are orthorhombic, space group D:6,-Pnrna, with a = 10.143, 9.865, 10.277, and 10.331, b = 3.342, 3.305, 3.475, and 3.332, c = 16.450, 16.601, 17.144, and 16.591 A, respectively, and Z = 4 . In Cs2In6Ol0,the InO, octahedra are linked in double three-membered blocks in the [OlO] direction by common edges and corners. The cations occupy channels along [010].268 Calorimetric measurements of the enthalpy of reaction of caesium hydrogen acetylide with water have been combined with auxiliary thermochemical data to derive the standard enthalpy of formation AH&8= 18.84 kcal mol-' for the compound. The compound is probably considerably unstable with respect to its The reactions of caesium sulphur pentafluoride with some halogen derivatives have been investigated. Mixtures of CsSF,, CsF, and BrCN at - 183 "C, subsequently heated to 55 "C, produced CF,NSF,. At ambient temperatures, CsSFs reacts with S02FC1,forming SOzF2,SF3,and a chlorinecontaining solid. The compounds PF2C1, BCl,, and S02C12are fluorinated by CsSF, but NOCl and N0,Cl break up the caesium compound, producing SF, and SF,Cl, respectively, among other products; CsSF, does not react with SF,Cl at 150"C.270A study of the behaviour of crystalline caesium selenite hydrate Cs,SeO,,H,O during heating to 1000°C in air by thermal, chemical, X-ray, and i.r. spectral analyses indicates that, at 100-1 30 "C, 264 265 266

267 268 26y

270

L. Zviedre, I. Ozols, and A. Levins, Law. P.S.R. Zmat. Akad. Vestis, Kim. Ser., 1973, 387. J. Krogh-Moe, Acta Cryst., 1974, B30, 1178. V. N. Plakhotnik, N. G. Parkhomenko, and V. V. Evsikov, Zhur. neorg. Khim., 1974, 19, 1260. T. N. Dymova and Yu. M. Dergachev, Doklady Akad. Nauk S.S.S.R., 1973, 211, 857. D. Fink and R. Hoppe, Natuwiss., 1973, 60, 430. M. Ader and W. N. Hubbard, J . Chem. Thermodynamics, 1973, 5, 607. M. D. Vorob'ev, A. S. Filatov, and M. A. Englin, Zhur. obshchei Khim., 1973, 43, 2386.

Elements of Group 1

55

0.5 molecules of water and CsOH are lost. At 210”C, complete dehydration occurs, with the sublimation of CsOH and the disproportionation of SeO, to Se. At 330-440°C, selenite is partially oxidized to selenate, and the oxidation is complete at 810°C. In the absence of air, the decomposition proceeds similarly except for the oxidation to ele en ate.'^^ Caesium or rubidium fluoride react almost completely with TeF6, if the alkali-metal fluorides are suspended in the inert solvent hexafluorobenzene, to produce CsF,TeF, or 2RbF,TeF6. Thermogravimetric analyses of the products show various inflection points, indicative of intermediate products that are stable, at higher temperatures. Complete decompositjon is not achieved up to the melting points of the alkali-metal fluorides except under prolonged pumping. The i.r. and Raman spectra of the complex fluorides are tentatively interpreted in terms of D,, and D,, structures for the [TeF,]- and [TeFJanions, Caesium chloride can be separated from rubidium chloride equimolar aqueous solutions by molecular sorption chromatogin the raphy on caesium copper ferrocyanide, C~~,~~_l.~~C~~.66-1.~[Fe(~~)6] presence of 1M-NaC1.273Complexometric determination of caesium and rubidium can be achieved after precipitation as caesium or rubidium calcium hexacyanoferrates(I1). The heavy alkali-metal ion M is precipitated by adding calcium chloride and sodium hexacyanoferrate(11) and cooling, when M,Ca[Fe(CN),] separates. This is dissolved in 2M-HCl, the pH is adjusted to 12 using 2M-NaOH, and the calcium is titrated with 0.01MH,edta. Each Co is equivalent to 2 M ions. The ions K’, Mg”, NK’, and SO:- interfere. 274

13 Molten Salts Structural studies in fused salts by means of careful and thorough hightemperature measurements of electrical conductivity, density, viscosity, and laser-Raman spectroscopy have been reviewed. Four problem areas are discussed: (1) melting mechanisms of ionic compounds with large polyatomic cations, (2) salts as ultra-concentrated electrolyte solutions, (3) structural aspects and Raman spectroscopy, and (4) electrolysis of molten carbonates. The results in these areas are summarized and significant contributions to new experimental techniques for molten-salt studies are The physical properties and structure of molten salts have also been reviewed in terms of operational (hole, free volume, partly disordered crystal) and a priori (intermolecular potential) models.276Electrochemistry T. V. Klushina, 0. N. Evstaf’eva, N. M. Selivanova, V. V. Lapin, Yu. M. Khozhainov, and G. E. Kalenchuk, Zhur. neorg. Khim., 1974, 19, 302. ’” H. Selig, S. Sang, and S. Abramowitz, Inorg. Chem., 1974, 13, 1508. 273 E. A. Shul’ga, V. V. Vol’khin, and S. A. Kolesova, Izuest. V.U.Z.,Tsvet. Met., 1973, 16, 109. 274 K. Boguslawska and A. Cyganski, 2. analyt. Chem., 1974, 268, 285. G. J. Janz, U.S. Nut. Tech. Inform, Seru., AD Report, 1972, No. 764970/0. 276 H. Bloom and I. K. Snook, Modern Aspects Electrochem., 1974, 9, 159. 271

”’

56

Inorganic Chemistry of the Main -group Elements

of molten salts has been reviewed277and so has the solubility of reactive gases (halogens, C 0 2 , SO,, SO,, HHal, metal halide vapours) in this medium; thermodynamics, solution mechanism, and experimental methods have also been Nitrates.-The solubilities of hydrogen and of carbon dioxide have been measured in molten equimolar NaN0,-KNQ, at 500-600 K. The solubilities, KH,for hydrogen and carbon monoxide, respectively, are given by: log(K,/mol ~ r n bar-') -~

= -5.39-

(768 K/T)

log(K,/mol cmP3bar-')

= -5.98 - (980 K/T)

Unusual rates of solution were obtained since both gases reacted with the solvent according to:

H, (8)+NO; and

-+

NO;

+ H 2 0(g)

CO(g)+NO; -+ NOY+CO;(g)

Modest interaction between C O and solvent is indicated since the enthalpy of solution is 18 kJ mol-' and is comparable to that of the inert solutes He, Ar, 02,and N,. Strong solute-solvent interactions give small or negative enthalpies of solution. The negative entropies of solution for both H,(AS533= -22 J K-' mol-l) and C O (ASo= -26 J K-' mol-') indicate a limited structuring of the solvent by solute and are directly comparable with inert gas-(Na,K)NO, systems, where AS"= -23, -28, -31, and -34 J K-' The work was extended to mol-' for He, Ar, 02,and N,, re~pectively.~'~ cover solubilities of carbon dioxide and ammonia in NaN0, (or LiN0,)KNO, at 470-670K. The enthalpy of solution becomes negative for the polar solvents (NH, and H20)whilst assuming an intermediate value, close to zero, for CO,. In general, the dissolution of the polar gases NH,, H 2 0 , and CO, appears largely influenced by solute-solvent interaction energies."O The vaporization of CsNO, has been investigated by mass spectrometry. The enthalpies of vaporization of monomeric CsNO, (g) and dimeric (CsNO,), are 28.2 and 29.3 kcal mol-I, respectively, at 298 K. The enthalpy of dimerization of caesium nitrate is -27.1 kcal mo1-I at 298 K."" The thermal decomposition of potassium oxalate in molten KNQ, at 350 "C yields K,CO,, KN02, and CO,. There was no trace of carbon monoxide.'*' The extraction of CoII and some 4f (Pr, E u , Tm) and Sf (Am, Cm, Cf) 277

278 279 280 281

282

D. Inman, J. E. Bowling, D. G. Lovering, and S. H. White, in 'Electrochemistry', ed. H. R. Thirsk (Specialist Periodical Reports), The Chemical Society, London, 1974, Vol. 4, p. 78. S. N. Flengas and A. Block-Bolten, Adv. Molten Salt Chem., 1973, 2, 27. E. Desimoni, F. Paniccia, and P. G . Zambonin, J.C.S. Paraday I , 1Y73, 69, 201.4. F. Paniccia and P. G. Zambonin, J.C.S. Faraday I, 1973,69,2019, L. L. Ames, J. Ling-Fai Wang, and J. L. Margrave, Inorg. Nuclear Chem. Letters, 1973, 9, 1243. A. G. Keenan and C. G. Fernandez, J. Electrochem. Soc., 1973,120, 1697.

57

Elements of Group I

elements from LiN0,-KNO, eutectic by diphosphine oxides Ph,P(O)CH2),P(0)Ph,, where n = 2, 3, 4, 5, or 6, has been studied. These organophosphorus compounds contain two P(0) groups separated by a variable number of CH, groups. An attempt was made to use the results obtained for the CoII distribution to develop a selective liquid membrane electrode for determining the activity of the transition-metal ion in LiN0,-KNO, eutectic at 160 0C.283Raman spectroscopy of molten binary mixtures of Mg(N03)2 with NaNO, and KNO, shows a doubling of the symmetrical stretching mode of NO; as well as some multiplicity of other frequencies. This suggests that NO; is in two different environments. Two types of cavity potentials fit the results in preference to the possibilities of either a perturbed lattice structure with dynamical coupling of the anion or the presence of distinct complex ions. Comparison between the Mg(NO,), salts and a highly concentrated aqueous solution of Mg(N03)*suggests that the appearance of new vibrational frequencies is attributable to a new potential cavity being formed as the cation enters the cavity surrounding NO; and not to direct complex formation.284The reaction of C10; ions with C1- ions has been studied in a mixture of fused alkali-metal nitrates containing Ba" ions through which was passed a stream of carbon dioxide. At temperatures between 420 and 450 "C the dependence of the rate of C10; reaction on the flow rate of CO, was linear. Reaction orders with respect to individual components were half-order, with activation energies of ca. 40 kcal m ~ l - ' . ~ ~ ~ With bromide and bromate ions as reactants in NaN0,-KN03 eutectic at 260-290°C, doped with Ba" and agitated with COa, the reaction orders for the Br- oxidation are 0.6, 0.6, and 1 with respect to CO,, Ba2+,and Brconcentrations, respectively.286Iodide ions do not react with iodate ions at 340 "C in the absence of CO, in this medium. In the presence of COz, iodine is formed at a rate which is first-order with respect to I- concentration and the partial pressure of CO,. The reaction proceeds according to: 10; + 51- + 3 0 ,

-+

31, + 3CO:-

and, furthermore, depends on the flow rate of C02.287 Halides.-Methods used to obtain interionic distances in liquid alkali-metal halides have been critically discussed, and a new set of estimated interionic distances for these liquid salts has been recommended for use in the evaluation and correlation of thermodynamic data for simple alkali-metal halide mixtures. The new distances are in good agreement with X-ray data. The ionic radii on which the distances are based are shown in Table 8 and are derived from recent crystallographic data for solids using Pauling's 283 284 285

286 '71'

J. Mesplede, Report 1972, FRNC-TH-368. M. Peleg, J. Phys. Chem., 1973, 77, 2252. I. Horsak, I. Slama, and Z . Kodejs, Coll. Czech. Chem. Comm., 1973, 38, 2833. Z . Kodejs, I. Horsak, and I. Slama, Coll. Czech. Chem. Comm., 1973,38,2839. P. Pacak and I. Slama, Coll. Czech. Chem. Comm., 1973, 38, 3595.

58 Inorganic Chemistry of the Main -group Elements method. The new interionic distances for the crystal are given by ( r c + rA)mod,fiedThe estimated interionic distances for the liquid are calculated from the empirical relationship d,,, = (rc+ r A ) + 0.42A, since it was found that &/Al, where A, = dcnlstal - (rc + r A ) and A, = dliquld - ( I c + YA), was remarkably constant (except for LiBr) and yielded an average value of 0.42.'88An apparatus has been developed which uses a resistance manometer to measure saturated vapour pressures and the temperature of highly volatile salt melts of sample size smaller than 2 g. When tested with KCl and PbCl, at 658-1 193 "C and vapour pressures of 3.5-345 Torr, the results showed good agreement with known data.28Y Table 8 Interionic distances in alkali-metal halides

rAa/A Halide

rca/A

Ion

Li'

0.57

F-

1.34

Na'

0.96

C1-

1.81

K'

1.34

Br-

1.95

Rb'

1.49

I-

2.17

CS'

1.68

Ion

LiF LiCl LiBr LiI NaF NaCl NaBr NaI KF KCl KBr KI RbF RbCl RbBr RbI CsF' CSCl CsBr CSI

rc and rA = new ionic radii for cations and anions; ( r c + radii; d,,, = interionic distance in the liquid halide.

a

d e A for liquid'

1.91 2.38 2.52 2.74 2.30 2.77 2.91 3.13 2.68 3.15 3.29 3.51 2.83 3.30 3.44 3.66 3.02 3.49 3.63 3.85

1.95 2.46 2.62 2.85 2.30 2.79 2.94 3.18 2.68 3.15 3.29 3.52 2.83 3.30 3.44 3.66 3.01 3.49 3.62 3.85 = sum

of new ionic

The influence of atmosphere on the dissolution of lithium in molten LiCl has been studied both with sealed-type and open cells. The true solubility of Li determined in the sealed cell is 0.66 mol % at 662°C. Using an open cell, the solubility apparently increased with time, owing to the reaction of the metal with atmospheric nitrogen, oxygen, and water vapour. It is suggested that in addition to a true solution of the metal, further amounts can be held suspended in the salt by the emulsifying action of Li,O and Li,N.'9" At 1143 and 1293 K, solutions of sodium in liquid NaCl exhibit 288 28y

M. E. Melnichak and 0. J. Kleppa, Reu. Chim. mine'rale, 1972, 9, 63. V. T. Barchuk and P. G. Dubovoi, Ukrain. khim. Zhwr. (Russ. Edn.), 1973, 39, 838. N. Watanabe, K. Nakanishi, and T. Nakajima, Nippon Kagaku Kaishi, 1974, 401.

Elements of Group I

59

strong positive deviation from ideality. The activities, activity coefficients, and free energies have been calculated for the The electrical conductivities of molten NaCl containing dissolved Na( 1-3 mol O/O) at 840°C and of NaCl (57.9%)-CaCl2 containing 1 - 4 . 5 mol YO Na at 600850 "C increase by 30-50% with increasing temperature and metal concentration. Initial additions of metal cause especially high conductivity. It was presumed that this effect was due to electronic conduction occurring by electron jump between the cation and complex ions of the one-electronbond type [NaNa]', [CaCa]", [NaCa]'+, and [NaCaNa]2+.292The system NaC1-CaC1,-CaC,-CaO has been investigated to determine the activities of the constituents as they relate to the production of metallic sodium by the reaction : 2NaCl+ CaC,

+ CaC1,

+ 2Na (g) + 2C

The process is most efficient when the ratio NaCl:CaCz is 2, and this is explained as being due either to the formation of a complex in solution between Na' and C;- or to the slow production of the metal followed by its dissolution in the molten salt. The two further processes were studied at 830 and 930°C: CaC2(s) + CaCz (soln in melt) NaCl (s) + NaCl (g) The overall reaction to produce sodium was found to be first-order at 830 "C, with the reaction mechanism: Cf- + Na' + 2C + NaO + eand

Na'

+ e- + Na"

or formation of an intermediate acetylide according to:293 2NaCl+ CaC2+ Na,C, and

+ CaCl,

Na2C2+ 2Na" + 2C

The distributions of Li and Bi between liquid Li-Bi alloys and molten LiCl have been measured at 650-800°C. The extent of their distribution to LiCl increased at each temperature with a moderate increase in the Li concentration of the alloy; at 650 "C, the Bi concentration in LiCl increased from ca. 5 to 4800 p.p.m. as the Li concentration in the alloy increased from 10 to 50 mol YO. The ratio of excess Li to Bi in LiCl was generally ca. 3, suggesting that salt-like Li,Bi was selectively dissolved from the alloys. 291

292

293

A. G. Morachevskii and F. I. L'vovich, Zhur. priklad. Khim., 1973, 46, 2640. M. V. Smirnov, N. P. Podlesnyak, V. Ya. Denishchenko, A. F. Shafranets, and V. B. Busse-Machukas, Trudy Inst. Electrokhim., Ural. Nauch. Tsentr. Akad. Nauk S.S.S.R., 1972, No. 18, p. 10. G. Bienvenu, C. Gentaz, and A. Boussiba, Rev. Internat. Hautes Temp. Refract., 1974, 11, 61.

60

Inorganic Chemistry of the Main -group Elements

The measured equilibrium Bi concentrations in LiCl can be expressed as:

+ 2.579NLi(,,+ 2.21 1 ln(Nsi(d))= 4 In NLi(m) - (9465

K/T) + 0.0832 exp(3090 K/T)

where N , (d), and !m) denote molc fraction, salt phase, and alloy phase, respectively. Data obtained with molten LiBr at 650°C showed that Bi concentrations in LiBr were about twice those obtained with LiCl under the same conditions.294The solubility of chlorine in molten LiCl-KCl has been determined at 450-575 "C. The amount dissolving is as low as lo-" moll-' and the enthalpy of solution is positive, as is that for noble gases in molten The solubility of gaseous tellurium in molten Li,BeF, is very low, ca. weight % at 655 "C. Solutions of Li,Te in Li,BeF, at 620 "C exhibit no absorbance in the range 200-2000nm attributable to TeZ-species. In the presence of elemental Te, however, Li,Te forms a complex Li,Te,, which dissolves to exhibit a spectrum (maximum absorbance 478 nm) similar to that of dissolved LiTe,. Although this is not sufficient proof to confirm that the dissolved species is Te;, it sets a maximum limit of three for the ratio n/m of the solute Te7.296The solubilities of chlorine in the LiCl-KCl eutectic as determined by an isobaric variation of the Sievert's method are 1.115, 1.318, 1.490, and 1.650g cm-' at 400, 500, 600, and 700 "C, re~pectively.~~' The kinetics of dissolution of HC1 in molten NaCl, KCl, RbCl, and CsCl are diffusion-controlled at 978-1260 K. The activation energies for the dissolution process are 8.13, 10.70, 12.90, and 16.00 kcal mol-', In a melt of LiCl-KC1, the oxidation of iodide by iodate is accompanied by the formation of the sparingly soluble Li,I0,.299 With oxygen in place of iodate, LiJO, and I, are formed. The 10:- ion reacts with 1- in the presence of CO, to form I, and CO:-.300At 400500"C, H,S reacts in the melt according to: H2S + C1-

-+

HS- + HCl

The HS- ion is the main product in the melt.301For the oxidation of sulphite by oxygen at 414--504"C, the rate is first-order with respect to the pressure and is independent of the concentration of SO:- ions formed. The activation energy for the oxidation is 15 kcal m ~ l - ' . ~A' ~cell using NaCIKCI eutectic as the electrolyte at Pt I O2 and Pb I PbClz electrodes has been 2y4

295

296 297

298 2YY

300 301

'02

L. M. Ferris, M. A. Bredig, and F. J . Smith, J. Phys. Chem., 1973, 77, 2351. T. Nakajima, H. Imoto, and K. Nakanishi, Denki Kagaku, 1974, 42, 85. C. E. Bamberger, J. Young, and R. G. Ross, J. Inorg. Nuclear Chem., 1974, 36, 1158. L. P. Kostin, Yu. G. Prasolov, A. N. Ketov, and V. E. Zhuravlev, Tr. Estestvennonauch. Inst., P e m . Uniu., 1972, 13, 205. A. L. Novozhilov, V. N. Devyatkin, and E. I. Pchelina, Zhur. fiz. Khim., 1974, 48, 57. P. Pacak, I. Slama, and I. Horsak, Coll. Czech. Chem. Comm., 1973, 38, 2347. P. Pacak and I. Slama, Coll. Czech. Chem. Comm., 1973, 38, 2355. J. Mala, J. Novak, and I. Slama, Coll. Czech. Chem. Comm., 1973, 38, 3032. P. Pacak, J. Novak, and I. Slama, Coll. Czech. Chem. Comm., 1973, 38, 3589.

Elements of Group I

61

Table 9 The system LiF-BeF,. Average number Nikof ions k around any origin ion i; average distances rik Species (Temperature) BeF, (700 "C)

1

k

Be F

F F F F F F F F F F

LiBeF, (400 "C) Li2BeF, (555 "C)

F Li,BeF, (750 "C) Li,BeF, (745 "C)

Li F Li

LiF (875 "C)

F F F F F F F F F

N k

4.0 6.0 4.0

: "q

1 8

4

5

4 4.0

;

> 8

;

}9

4 4

4 8 3

rikiA 1.589 2.544 1.58 2.563 3.02 1.85 1.58 2.563 3.02 1.85 1.58 2.563 3.02 1.85 1.58 2.56 3.02 1.85 3.02 1.85

used to study acid-base reactions in the Lux sense at 700°C. In potentiometric titrations using NaOH and Na'CO, the following equilibrium constants were

2po; + 0'- = p20;-

2.9 x 10'

p20:- + 0'- = 2po:PO; + 0'- = Po:-

2.5 x 10

co,+ 0'- = c0;PO;

+ C0:- = PO:- + COz

5 . 6 10' ~

2.5 0.5 X 10'

Measurements of the saturated vapour pressure of LiC1-CsC1 mixtures at 740-960 "C show that negative deviation from ideal behaviour exists in the system, and they reflect the formation of the complex [LiC1,]3-.304X-Ray diffraction data on the liquid salts LiF and BeF', and the compositions 4LiF,BeF2, 2LiF,BeF2, and LiF,BeF, at 875, 700, 745, 555, and 4OO0C, respectively, have been analysed to yield average nearest-neighbour distances and co-ordination numbers. The results are shown in Table 9. There 303

304

Yu. K. Delimarskii, V. I. Shapoval, 0. G. Tsiklouri, and V. A. Vasilenko, Ukrain. khim. Zhur. (Russ.Edn.), 1974, 40, 8. M. V. Smirnov, V. Ya. Kudyakov, and L. K. Khalturina, Tr. Ural. Politekh. Inst., 1973, 220, 18.

Inorganic Chemistry of the Main -group Elements

62

is a continuous increase of the mean distance between ions of opposite charge from 1.59 A in BeF, to 1.85 A in LiF. Similarly, the mean distance between neighbouring fluoride ions increases from 2.54 to 3.02A. The structure data are consistent with tetrahedral co-ordination throughout for Be in BeF:- units joined at each corner. With increasing LiF concentration the regular network becomes progressively distorted but the Be2' ions retain their immediate tetrahedral environment. The Li' ions occur in local and instantaneous environments that are grossly distorted from average tetrahedral c o - ~ r d i n a t i o n . The ~ ' ~ Knudsen effusion method has been used to vaporize KF-BeF, mixtures and the vapours have been analysed by mass spectrometry. The saturated vapour contains the ions K', K2F+,K,F;, BeFS, BeF', Be', Be,F:, KBeF:, and K,BeF:. The last two ions could only originate from complex molecules KBeF, and (KBeF3), in the vapour. At 1058 K, AG = 31.1 kcal mol-' for the reaction: KBeF, (g) = KF (g) + BeF, (g) and AH = 64.1, assuming the entropy of dissociation to be 31.2 cal K- ' m01-1.306 The vapour pressure above NaCl-BiCl, melts at 350-840 "C has Table 10 Phase diagrams that have been investigated Components

Compounds

Ref.

LiC1-NaCI-CsC1

LiCI,NaCI, LiC1,2NaCl, 309 LiC1,CsCl (d. 352 "C), LiC1,2CsCI (d. 382 "C) LiC1-RbC1-CsC1 LiC1,2CsCI 310 LiBr-NaBr-RbBr LiBr,RbBr, LiBr,NaBr, 311 LiBr,2NaBr LiBr-KBr-CaBr, KBr,CaBr, (m.p. 605 "C), 3CaBr,2LiBr (incongruent m.p. 418 "C) 312 KCI-SrCI, K,SrCI,, KSr,Cl, 313 KBr-SrBr, K,SrBr,, KSr,Br, 313 CsCl-CaC12 CsCaC1, 3 14 RbBr-Rb,CO, 2RbBr,Rb,CO, (m.p. 615 "C) 315 316 MBF, (M = Li, Na, K, Rb, or Cs) MBF,-MF 316 KCI-Li, AlF, 3 17 LiF-AlF, Li, AIF, 318 NaF-AlF, Na7A1F, 318 Li,AIF6-Cs,AIF, Cs,LiAIF,, orthorhombic, 3 19 a = 6.21, b = 10.72, c = 4 A, d(expt) = 4.04, and d(ca1c) = 4.14 for Z = 2 RbCI-TIC1 320 KX-RbX-PbX, KX, 2PbX2, 2KX,P bX, , 32 1 RbX,2PbX,, RbX,PbX,, (X = C1 or Br) 2RbX,PbX, 305 306

F. Vaslow and A. H. Narten, J. Chem. Phys., 1973, 59, 4949. A. N. Rvkov, Tu. M. Korenev, and A. V. Novoselova, Zhur. neorg. Khim., 1973, 18, 2493.

Elements of Group I

63 been measured by a static method employing a quartz null manometer. The composition of the vapour was determined by gravimetric analysis and by flame photometry. Both (NaCl), and NaBiC1, molecules were detected in the gas phase. At 350-65O0C, the enthalpy and entropy for the dissociation: NaBiCl,

= NaCl

+ BiCl,

were estimated to be 54.0 kcal mol-' and 38.0 e.u., re~pectively.~'~ The Raman spectra of PbC1, and its mixtures with KCl have been determined at 505 "C. Fused PbCl, shows absorptions at 120 (depolarized) and 205 cm-' deformation mode (polarized). These can be assigned to CI-Pb-Cl (v,, El) and Pb-CI stretching mode (vl, Al), respectively, since [PbCl,]ion-like local structure is predominant in the fused state. A chemical shift of the 205 cm-' line to 230 cm-' occurs with increasing KCl concentration, indicating that the chain structure of the [PbCI,]- ions is broken into individual [PbCl,]- ions.3o8Some phase diagrams that have been investigated are shown in Table 10.309-321 N. V. Karpenko, Vestnik Leningrad. Uniu. (Fiz. Khim.), 1973, 89. R. Oyamada, J. Phys. SOC.Japan, 1974, 36, 903. 309 T. P. Bortnikova, E. K. Akapov, and V. A. Ocheretnvi, Zhur. neorg. Khim., 1974, 19, 1066. 310 I. I. Il'yasov, M. Davranov, and I. I. Grudyanov, Zhur. neorg. Khim., 1974, 19, 1710. 311 R. V. Chernov and V. V. Bugaenko, Zhur. neorg. Khim., 1973, 18, 3096. 312 I. I. II'yasov, K. I. Iskandarov, and A. G. Palobekov, Izuest. V.U.Z., Khim. i khim. Tekhnol., 1974, 17, 611. 313 V. N. Prokhorov, I. V. Krivousova, I. I. Kozhina, and A. I. Efimov, Vestnik Leningrad. Uniu. (Fiz. Khim.), 1974, 89. 314 B. F. Markov, T. A. Tishura, and A. N. Budarina, Ukrain. khim. Zhur. (Russ. Edn.), 1974, 40, 242. 315 G. G. Diogenov and V. F. Kirillova, Zhur. neorg. Khim., 1973, 18, 2830. 316 H. Ohno and K. Furukawa, Report 1972, JAERI-M-5053. 317 K. Matiasovsky, I. Kostenska, and M. Malinovsky, Chem. Zuesti, 1973, 27, 301. 318 K. Matiasovsky and V. Danek, J. Electrochem. SOC., 1973, 120, 919. 319 M. Amorasit, B. J. Holm, and J. L. Holm, Acta Chem. Scund., 1973,27, 1831. 320 A. Haav, T. Muuresepp, and A. Kiisler, Kristallografiya, 1974, 19, 273. 321 M. Davranov, I. I. Il'yasov, and M. Ashurova, Zhur. neorg. Khim., 1974, 19, 1628. 3"7

308

2 Elements of Group II BY R. J. PULHAM

In this Chapter, references which allude to several members of the group appear once only under the element first mentioned. The elements of Groups I1 and I are so closely linked in the field of ‘Molten Salts’ that, to avoid duplication, this section appears once only and can be found in Chapter 1.

1 Beryllium Beryllium reacts with both polycrystalline and single crystals of tungsten to produce the same products. At 700-1200 “C, the phases Be2W ( a = 4.44, c = 7.30 A) and BezzW ( a = 7.24, c = 4.21 A) are formed.’ The determination of the molecular structure by X-ray diffraction of the compounds of beryllium, magnesium, calcium, strontium, and barium has been reviewed.’ The compound BeB, is hexagonal, space group P6/mmrn, with a = 9.800, c = 9.532 8, and 82 boron and 27 beryllium atoms in the unit cell. The structure is built upon pairs of polyhedral (BeB),, units. The B-B, B-Be, and Be-Be distances are 1.62-1.84, 1.90-2.22, and 2.04-2.11 A, re~pectively.~ The Raman spectra of molten Be(N0J2,20H20, Be(N0,)2,4H,0, A1(N0,),,20H2O, and AI(N0,),,9H20 have been recorded and analysed in terms of vibrational modes arising from aquated metal ions, NO; ions, H 2 0 molecules, and hydrolysis products. For Be(NOJ2,4H20,though not for the aluminium salts, the spectra suggest a significant degree of proton transfer from [Be(H20)4]2+to NO;. Solvent-separated metal-NO; ion pairs appeared to be present in all melts.4 The solubility of beryllium oxide, BeO, in aqueous solutions of the alkali-metal hydroxides increases with increasing alkali concentration. With

’ E. A. Vasina and A. S. Panov, Izuest. A k u d . Nauk S.S.S.R., Metal., 1974, 197. ’ M. B. Hursthouse, in ‘Molecular Structure by Diffraction Methods,’ ed. G. A. Sim and L. E. Sutton (Specialist Periodical Reports) The Chemical Society, London, 1973, Vol. 1 , p. 797. R . Mattes, H. Neidhard, H. Rethfield, and K. F. Tebbe, Inorg. Nuclear C h e m . Letters, 1973, 9, 1021. D. J. Gardiner, R. E. Hester. and E. Nayer, J. Mol. Structure, 1974, 22, 327.

64

Elements of Group I1

65

dilute solutions of lithium and sodium hydroxides, B e 0 does not react, but with potassium hydroxide the oxide is hydrated, 3BeO,H,O. At higher alkali concentrations polyberyllates are produced, but the degree of polymerization and the water content of the hydrate diminish in very concentrated solution^.^ Potassium oxoberyllate, K,Be,O,, has been prepared by heating 2.2: 1 K,O : B e 0 mixtures to 600 "C for extended periods. The crystals are monoclinic, space group C:,,-P2/b, with a = 7.09, b = 10.57, and c = 5.70 A, y = 131.3", d(expt) = 2.5, and d(ca1c) = 2.46 for Z = 4. The structure consists of planar dinuclear isolated (BeO), groups as edge-linked triangles. The Madelung part of the lattice energy was calculated to be 1939.7 kcal mol-1 and was approximately equal to the sum of the values for the constituent oxides6 The enthalpy of solution of beryllium in molar sulphuric acid has been determined calorimetrically and the data have been combined with known enthalpies of solution of beryllium sulphate hydrates in sulphuric acid to redetermine the standard enthalpies of formation of BeSb, and its hydrates. These are given in Table 1.'

Table 1 Enthalpies of formation of beryllium sulphate and its hydrates -AHf,298/kcalmol-' Reaction Be(c) + S(rhombic)t-202(g) +. BeSO,(c) Be(c) + S(rhombic) + 202(g)+ 2H2(g) + BeS04,2H20(c) Be(c)+ S(rhombic) +4H2(g) + 402(g) + BeS04,4H20(c)

*

Ref. 7

288.0 *0.1 435.7 k0.1

287.0 0.1 434.7k0.1

286.62 0.5 434.4*0.6

579.3k0.1

578.3*0.1

578.0*0.5

*

t

*,tOther previous determinations Calculation by the crystal-force-field method of the charge density on the F atom, the stretching force constant for the Be-F bond, and the length of the Be-F bond in crystalline LizBeF, show that the Be-F bonds have some covalent character and that there is probably weaker covalent bonding between the Li and F atoms.' The compound y'-Na2BeF4 is monoclinic, space group P2,/n, with a = 5.559, b = 8.070, c = 7.910 A, p = 99"21', and Z = 4. The structure consists of serrated chains of Na-centred octahedra linked by Be-centred tetrahedra. There are two distinct octahedral sites, occupied by Na-1 and Na-2, characterized by extreme distortion, as shown in Figure 1. The Na-1-F distances range from 2.280 to 2.540 A, and from 2.272 to 2.469 A for Na-2-F. The beryllium-centred BeF, tetrahedra are also severely distorted and have angles (mean 109"04') consistent with sp3 hybridization.' The structures of chloroberyllate anions in the compounds MiBeCl, and M'Be,Cl, (M=Tl+ or NO') have been studied by i.r. and B. J. Losev, R . F. Doronkina, and I. V. Vasil'eva, Zhur. priklad. Khim., 1973, 46, 1664. P. Kastner and R. Hoppe, Naturwiss., 1974, 61, 79. ' J . D. Navratil and F. L. Oetting, J. Inorg. Nuclear Chern., 1973, 35, 3943. J. A. McGinnety,-J. Chem. Phys., 1973, 59, 3442. S. Deganello, Acta Cryst., 1973, B29, 2593. ti

66

Inorganic Chemistry of the Main -group Elements

F(1

Figure 1 Dimensions of co-ordination octahedra around the sodium atoms in y'-Na,BeF,. Shared edges are shown by thick lines (Reproduced by permission from Acta Cryst., 1973, B29, 2593) Raman spectroscopy and subjected to (LCAO-MO)CND0/2 calculations. The vibrational spectra are compatible with a higher degree of anionic distortion in the NO' complexes than in those of Tl', and indicate that the ion [Be2C1,]- in TlBe,Cl, may have molecular symmetry similar to that of the polymeric BeCl chain. The C N D 0 / 2 calculations favour a dimeric structure for [Be,Cl,]-.'O New pentadichlorodiberyllates MBe,Cl, (M = K', Rb', or NH,') have been prepared by the reaction of anhydrous BeCl, with the corresponding alkali-metal halides at 2 : 1 molar ratio under nitrogen at 400°C. Identification was by X-ray, i.r., and Raman spectra." The crystal structure of hydrazinium fluoroberyllate, (N,Hs)BeF,, has been determined from X-ray data. The compound is monoclinic, space group P 2 , / c , with a = 5.568, b = 7.305, c = 9.910 A, 6 = 98-25", and 2 = 4. The structure consists of [BeF,]*- tetrahedra (mean Be-F distance = 1.547 A) and [N2H6]" ions linked by hydrogen-bonds.I2 The reaction of BeCl, with AIH, in ether has been followed by i.r. spectroscopy. The reaction proceeds according to: BeC1, + AlH, + HBeC1-t H,AICl HBeCl+ AIH, = BeH, + H2A1C1 Hydridoberyllium chloride was prepared unequivocally by the reaction of BeCl, with BeH, and shown to be the product of the above reaction. When excess AIH, is used, BeH, precipitates from solution, the yield depending on the amount of AlH, added. HBeCl is stable to disproportionation and is In

l' l2

J MacCordick and G. Kaufmann, Ann. Chim. (France), 1973, 8, 181. J . MacCordick, Chem. Ber., 1974, 107, 1066. M. R. Anderson, S. Vilminot, and I. D. Brown, Acta Cryst, 1973, B29, 2961.

67

Elements of Group I1 dimeric in ether, the dimer (1) being associated through Be-H-Be

c1'

'H'

bonds

OEt,

and showing bands at 1330, 1050, 970, 908, 840(sh), 790, and 700 cm-' in this s01vent.l~The reactions of LiAlH, and NaAlH, with BeCl, have been studied in 1 : 1 and 2 : 1 ratios in both Et,O and THF as solvents. No evidence for the previously reported Be(AlH,), was found. In 2 : 1 ratio the reaction of NaAlH, and BeCl, in THF was similar to the reaction of LiAlH, and BeC1, in Et,O. Two surprising aspects of the latter reaction are that the AlH, formed is soluble in Et,O and that a compound Li2BeH2C12can be isolated, rather than a mixture of LiCl and BeH,. The reactions proceed according to: 2LiAlH, + BeCl, + Li2BeH2Cl,+ 2A1H3 Li2BeH2C12 + 2A1H3= LiAlH,Cl + LiBeH,Cl + AlH, The reactions of LiAlH, and NaAlH, with BeC1, in 1: 1 ratio follow the same pattern.', Beryllium ethoxide chloride and solvates of beryllium chloride with ethanol have been isolated from mixtures of Be(OEt),-BeC1,EtOH at 20°C. The i.r. spectra of the compounds ClBeOEt,2EtOH and BeC1,,3EtOH have been measured.lS It has been known for a long time that BeCl, reacts with various aliphatic and aromatic nitrites to give complexes that are stable in the absence of polar solvents, i.e. BeCl,,2RCN, in which Be is tetrahedrally co-ordinated. An addition to this type of compound is beryllium chloride 2(monochlorine cyanide), BeCl2,2C1CN, prepared by the reaction of BeCl, with liquid ClCN. The properties of this compound have been compared with those of BeC1,,2MeCN. Both compounds are stable in an inert atmosphere but decompose at high temperatures; BeC12,2C1CN decomposes at ca. 120"C, but BeC1,,2MeCN at ca. 210°C; both are hydrolysed in water and are generally insoluble in nonpolar solvents. BeC1,,2MeCN is sufficiently soluble in hot MeCN to permit recrystallization. Ligand exchange occurs in nucleophilic solvents according to: BeC1,,2NCR+ 2L = BeC12,2L+2RCN (R = C1 or Me; L = Et,O, MeCN, or PhCN) The observed absorption y(C=N) occurs at 2287 and 2338cm-' for BeC1,,2CICN and BeC1,,2MeCN, respectively, compared with 2219 and l3 l4 15

E. C. Ashby, P. Claudy, and R. D. Schwartz, Inorg. Chem., 1974, 13, 192. E. C . Ashby, J. R. Sanders, P. Claudy, and R. D. Schwartz, Inorg. Chem., 1973, 12, 2860.

E. P. Turevskaya, N. Ya. Turova, and A V. Novoselova, Zhur. neorg. Khim., 1973, 18,2925.

68 Inorganic Chemistry of the Main -group Elements 2254 cm-’ for ClCN and MeCN, respectively.’6 Beryllium perchlorate dihydrate has been prepared by the reaction of BeCl, with HClO, followed by vacuum evaporation, and also by heating BeC1, with HClO,,H,O up to the melting point of the mixture. uiz. 60°C. The i.r. spectrum of the product reveals the presence of [Be(H,O),]” and [Be(ClO,),]”- ions. Be(C10,),,2H,O melts at 8O”C, and at 150°C an 0x0- or hydroxy-containing compound is formed. At 190-265 “C HClO, is lost, and the solid residue is Be4O(C10J6. Further heating to 290 “C yields BeO.” The i.r. (400-3700 cm-‘) and n.m.r. spectra of beryllium and aluminium nitrilotriacetates KBeX, HBeX,2H20, KBeX,2H20, A1X,4H20, and A1X [X = N(CH,CO,):-] and their deuteriated analogues have been measured. An equilibrium: B e X - + H 2 0 = Be(0H)HXduring which a mutual transition between two complex types, with N-Be and N-H bonds, occurred, was detected in aqueous KBeX,2H20 solution. This equilibrium was shifted to the right with acidification of the solution.’* A compound between dioxo-octa-acetatoberyllium and ammonia, Be6O2(0Ac),(NH3),,has been prepared by heating Be6O,(OAC), in

Figure 2 Schematic representation of a molecule of tri-p- hydroxo-tri(pyridine -2-carboxylato) triberyllium (Reproduced by permission from Acta Cryst., 1974, B30, 462) l6

J . MacCordick, Compt. rend., 1974, 278, C, 1177. L. R. Serezhkina, Z. I. Grigorovich, V. N. Serezhkin, N . S . Tamm, and A . V. Novoselova, Doklady Akad. Nauk S . S . S . R . , 1973, 211, 123. A. I. Grigor’ev, L. V . Nikitina, and N. I. Voronezheva. Zhur. neorg. Khim., 1973, 18, 1755.

Elements of Group II

69

liquid ammonia in a sealed arnp0u1e.l~ The crystal structure of tri-phydroxo-tris(pyridine-2-carboxylate)triberylliummonohydrate, Be,(OH)3(C,H,NCO,),,H,O, has been determined as monoclinic, space group P2,/c, with a = 15.914, b = 9.262, c = 15.480 A, p = 105.43”, and 2 = 4. The structure is shown schematically in Figure 2. Each Be atom is surrounded by a distorted tetrahedral arrangement of two hydroxide oxygen atoms ( 0 - 3 and 0 - 9 for Be-1) (Be-0 distance = 1.58 A) and the chelating nitrogen (N-1 for Be-1) and carboxylic (0-2 for Be-1) atoms of one picolinato-group (distances Be-0 = 1.65, Be-N = 1.‘79A). The oxygen atom of each hydroxide group (0-3, 0-6, and 0-9) is bonded to two beryllium atoms so that these atoms make a six-membered planar ring reminiscent of the cyclic arrangement (2) in [Be3(0H),]”, with average values Be-0 = 1.85 A,

LBeOBe = 229”. The planar picolinato-groups ‘are in the orthogonal position with respect to this ring. Two chelating N atoms (or two chelating 0 atoms) are located below the Be-0 ring while the third is above, as in a trans compound. The hydrogen-bonded water molecule is in an interstitial position.” Syntheses of new chelates, namely bis(3’-chloroacetoacetanilidato)beryllium(n), bis(4’-bromoacetoacetanilidato)beryllium(11), bis(2’,5’bis(acetoacet- 1‘dime thoxy-4’-bromoacetoacetanilidato)beryllium(11), naphthanilidato)beryllium(II), bis(3-nitro-3’-chloroacetoacetanilidato)beryllium(u), bis(3-nitro-4’-chloroacetoacetanilidato)beryllium(11), bis(3nitro-2‘,4‘-dichloroacetoacetanilidato)beryllium(11), and bis(3-nitro-2’,5’dichloroacetoacetanilidato)beryllium(II) have been described. The nitrocompounds were obtained by the reaction of the parent chelates or the ligands with Be(N03), in acetic anhydride. The i.r., n.m.r., and mass spectra of the compounds have been discussed.21The ability of organic solvents to and beryllium-5,7-dihalogeno-8extract beryllium-8-hydroxyquinoline hydroxyquinoline complexes decreases in the order: iso-CsHI1OH> PhNO, > CHCl, > C,H,Cl, > C,H, > hexane > CCl,.” 19

20

’’ 22

A. I. Grigor’ev, L. N. Reshetova, and A. V. Novoselova, Zhur. neorg. Khim., 1974, 19, 1995. R. Faure, F. Berth, H. Loiseleur, and G . Thomas-David, Acta Cryst., 1974, B30, 462. J. N. Patil, Indian J. Chem., 1974, 12, 189. A. I. Sevast’yanov and N. P. Rudenko, Vestnik Moskov. Uniu., Khim., 1973, 14, 233.

Inorganic Chemistry of the Main -group Elements

70 2 Magnesium

The Mg-Ga phase diagram has been investigated by d.t.a. and X-ray diffraction methods. The compound Mg,Ga, is formed in this system and melts peritectically at 200°C to decompose into MgGa, and melt. No high-temperature modification of MgGa, was detected.,' The laves phase Mg,LiZn, has been examined by X-rays, and the structure corresponds to the centrosymmetric space group P6,lmmc. There is a superstructure with ordered distribution of Li and Zn atoms in each layer, leading to a doubling of the cell dimension The crystallographic parameters and the temperature dependence of the electrical resistivity of Mg,Mn,-,Te, have been measured. The lattice parameter a increases smoothly with increasing temperature. Mgo32Mno 68Te2and MgTe, are semiconductors, like MnTe,. The activation energies for conduction are 0.48 eV for x = 0.32 and 0.42 eV for MgTe. The compounds MgTe, and MnTe, are essentially similar structurally and electronically, and they form a continuous solid solution over the entire composition range." The solubilities of MgSe and CdSe in PbSe, and the extent of non-stoicheiometry in the systems Mg,Pb,-,Se and Cd,Pb,_,Se, have been determined between 400 and 800°C. The solubilities appear retrograde in that the solubility of MgSe is less dependent on temperature than that of CdSe.'" The solubilities of Mg, Ca, Cd, Zn, and Hg in PbTe are compared at 250-800°C. Mg, with Cd and Zn, shows retrograde solubility in this melt Magnesium reacts with fused NaOH at 400°C to give MgO and NaH as primary products. Subsequently, NaH dissociates to produce gaseous hydrogen, and the sodium also liberated reacts with NaOH to produce NazO." The reaction of Mg with molten LiOH, NaOH, and KOH is considered to be insignificant, however, at low temperatures but increases sharply at 610, 570, and 540 "C for LiOH, NaOH, and KOH, respectively, only to decrease again at higher temperatures up to 900°C. As before, alkali metal and hydrogen are liberated.29 An investigation has been made of the energy shifts of the K1.,emission lines of magnesium, sodium, aluminium, and silicon in their binary compounds. The shift varies with the ionic character of the chemical bond, so as to form two straight lines for compounds of these elements. Thus the MgKl,, energy shifts of MgC2, Mg,N2, MgO, and MgF, followed one linear relationship, in agreement with theory, but those for the compounds of Mg W. Staehlin, J. Less-Common Metals, 1973, 32, 395. E. V. Mel'nyk and P. I. Kripyakevich, Kristallogrufiyu, 1974, 19, 645. 2 5 S. Anzai, K. Watanabc. M. Iwama, A . Morita, and S. Vanagisawa, Japan. J. Appl. Phys., 1973, 12, 1289. '' B. J. Sealy and A. J. Crocker, J. Materials Sci., 1973, 8, 1247. 27 B. J . Sealy and A. J. Crocker, J. Materials Sci., 1973, 8, 1731. 2R G. A . Vorob'ev and V. L. Kubasov, Zhur. neorg. Khim., 1974, 19, 339. 2 y V. K . Shcherbakov and S. I . Kuznetsov, Zhur. priklad. Khim., 1973, 46, 2.555. 23

24

71 Elements of Group I1 with Al, Sn, Bi, P, S, Br, and C1 followed another. Similar results were obtained for the compounds of Na, Al, and Si.'" The magnesium borides MgB, and MgB, have been prepared at high temperatures in a sealed molybdenum vessel from mixtures of the elements. By using an excess of Mg, the vapour pressure of the metal inhibited thermal decomposition of the compounds during the synthesis. MgB, i s orthorhombic, space group Pnam, with a = 5.464, b = 7.472, c = 4.438 A, and Z = 4 . The structure is based on chains of pentagonal pyramids of boron atoms in which the average B-B distance is 1.787A. Interchain B-B bonds of 1.730A are responsible for the three-dimensional framework. The magnesium atoms are located in tunnels and form zigzag chains. A comparison with the structures of ThB, and CrB, shows that the size of the metal atom plays an important role in the nature of the boron framework. The boron pentagonal pyramid in MgB, is a new feature of B-rich borides since this type of co-ordination polyhedron was previously found only in B,, icosahedra.31Magnesium chloride is reported to react with LiAlH,, LiBH,, and NaAlH, in ether to give Mg(AlH,),,LiAlH,. With mixtures of MgCl,, LiBH,, and NaAlH,, the compounds Mg(A1H4),,2LiBH, and NaCl are formed using a 1:2 :2 molar ratio of reactants. Using a ratio of 1: z= 3 :4 produces Mg(AlH,),,LiA1H,.32 The enthalpies and energies of formation of the magnesium carbonates nesquehonite (MgC03,3H,0) and hydromagnesite (5Mg0,4CO2,5Hz0) have been determined by combining enthalpy data from solution calorimetry in HCl with previously determined heat-capacity data. For are -412 and -473 kcal mol-', respecMgC0,,3H2O, AG& and tively. For 5Mg0,4C0,,5H20, the values are -1402 and -1557 kcal mol-', respe~tively.~~ The reaction of powdered magnesium with nitrogen yields Mg3N, with the anti-bixbyite-type structure. The nitride forms double nitrides with Si,N, and Ge3N, of the form MgSiN, and MgGeN,, respectively. These compounds possess the wurtzite structure, with a = 5.279 and 5.494, b = 6.476 and 6.611, c =4.992 and 5.165 A, respectively. A new double nitride, Mg,Ca,N,, is reported from the Mg3N,-Ca3N, The preparation of mangesium phosphide, MgP,, has been achieved from MgSiP, by melting it with a Bi-Pb-Sn (4:2: 1 weight ratio) alloy at 1100°C in a corundum crucible followed by slow cooling. The excess metal was washed away by alloying with mercury, revealing the new compound MgP,, which crystallized with the MgSiP,-type structure. Crystals are monoclinic, space E. Asada, Japan. J. Appl. Phys., 1973, 12, 1946. R. Naslain, A. Guette, and M. Barret, J. Solid State Chem., 1973, 8, 68. 32 K. N. Semenenko, B. M. Bulychev, and K. B. Bitsoev, Vestnik Moskou. Uniu., Khim., 1974, 15, 185. '' R. A . Robie and B. S. Hemingway, J. Res. U.S. Geol. Survey, 1973, 1, 543. 34 J. David, Rev. Chim. mine'rale, 1972, 9, 717, 30 3'

72

Inorganic Chemistry of the Main -group Elements

group P2,/c, with a = 5.142, b = 5.079, c = 7.518 A, and /3 = 98.64°.3' The structure of a-Mg,Sb, has been determined as space group P3m1, with a = 4 . 5 6 8 and c =7.229A. The structure is of the La,O,-type, with d(ca1c) = 4.02 for Z = 1. Single crystals for the X-ray work were prepared by cooling a melt of composition 3Mg + 2Sb with a small excess of Mg from 1100°C to ambient temperature under argon. The compound has a metallic appearance and is resistant to air. The structure can be described in terms of SbMg, units. Each of these units contains the crystallographically independent Sb atom and the two crystallographically different magnesium atoms Mg-1 and Mg-2, as shown in Figure 3. Six of the Mg atoms are

2')

Figure 3 Arrangement of magnesium atoms around Sb in a-Mg,Sb,. The bond lengths are given in A (Reproduced by permission from Acta Cryst., 1974, B30, 2006) arranged at the corners of a trigonal antiprism whose centre is occupied by the Sb atom. The seventh Mg atom approximates the Sb atom in the three-fold axis of the group. No short Mg-Mg distances are present in this structure, in contrast to the short Ca-Ca, Sr-Sr, and Ba-Ba distances in the compounds Ca,Sb,, CasBi,, Sr,Sb,, Sr,B, and Ba2Bi. With the magnesium compounds of the main Group V elements there is a negligible volume contraction from the original volumes of the individual components, in contrast to the corresponding compounds of Ca, Sr, and Ba, in spite of the more salt-like formulae of the Mg compounds. Presumably more extensive transfer of electrons occurs from the heavier alkaline-earth metal atoms than for Mg." Magnesium arsenate, Mg,AsO,, is tetragonal, space group 1 4 2 4 with a = 6.783, c = 18.963 A, d(obs) = 3.9, and d(ca1c) = 4.03 for Z = 6 . The structure was determined by X-ray diffraction on crystals 3%

36

'I. Ciibiiiski, k.Cisowaska, W. Zdanowicz, Z . Hcnkie. and A. Wojakowski, Krist Tech., 1974, 9, 161. M Martinez-Ripoll. A. Haase, and Ci. Brauer. Acta Cryst., 1974, B30, 2006.

Elements of Group I1

73

from a melt of MgCO, and AszOs.The structure contains two distinct AsO, groups, with average As-0 distances of 1.678 and 1.690 A. Two of the three Mg2+ions are octahedrally co-ordinated and the third occupies a site of 4 ~yrnrnetry.~~ The reaction of Mg and 0 atoms in matrices of Ar, Kr, Xe, and 0 at 20.4 K has been studied by i.r. spectroscopy in the region 2 0 0 4 0 0 0 cm-l. Reaction takes place, as evidenced by a band in the Mg-0 stretching region, reproducible in all matrices. Substitution by "0 isotope gives results that suggest that the absorption is due to Mg,O,, whose formation is supported by the crystal structure of the solid phase. It is suggested that the species is a planar six-membered ring of alternate Mg and 0 atoms with bond angles O M 0 100" and MgOMg 140".38The enthalpy of formation and heat capacity of MgO have been determined calorimetrically between 298 and 1600 K. The enthalpy/cal mol-' is given by:"

HT - H298 = 11.18 (T/K) + 0.00067 (T/K)' + 2.27 X 10' (K/T) - 4154 The lattice energies of the alkaline-earth metal oxides have been calculated from equations based on the Born model and containing terms accounting for van der Waals interactions. The results, in kcal mol-l, are MgO, -905; CaO, -815; SrO, -767; and BaO, -736. These lattice energies, when combined with the appropriate thermochemical data, give 149 f 8 kcal mol-' for the process O(g) 5 02-(g), which is less than most values previously calculated for this process. The new smaller value is attributed to the higher more accurate compressibilities used in evaluating the lattice energies of these oxides.,' The X-ray-stimulated photoelectron emission of single crystals of Mg(OH), has been studied. A marked anisotropy was observed in the valence-band region. For the 1010 plane, three maxima were found at 4.6, 8.8, and 12.0eV, which can be assigned to the TI,, E,, and A,, states, respectively, if regular 0, symmetry is assumed for the ligand field. For the 0001 plane the A,, band disappears, which is attributed to the fact that in Mg(OH), the octahedral symmetry is reduced to D,, by the special orientation of the O H dipoles parallel to the c - a x i ~ . ~ ' The K f3-emission and K-absorption spectra of chlorine in MgCl,, CaCl,, SrCl,, and BaC1, have been determined. The Kf3 emission spectra consist of a prominent band KP, and its sub-bands KPx and KP5, although the sub-bands are ambiguous in MgC12, as shown in Figure 4. Going to the metal chlorides of higher atomic number, the half-width of the KP, band (which is due to the transition 3p + 1s within the C1- ion) decreases, and the sub-band K& is clearly separated from the KP, band. This general feature has also been found for the KP-emission of the C1- ion in the 37 38 39 40 41

N. Drishnamachari and C. Calvo, Acta Cryst., 1973, B29, 2611. M. Spoliti, G. Narini, C. S. Nunziante, and G. De Maria, J. Mol. Structure, 1973, 19, 563. D. Sh. Tsagareishvili and G. G. Gvelesiani, Teplofiz. Vys. Temp., 1974, 12, 208. S. Canton, J. Chem. Phys., 1973, 59, 5189. F. Freund and L. H. Scharpen, J. Electron Spectroscopy Related Phenomena, 1974, 3, 305.

Inorganic Chemistry of the Main -group Elements

74

SrCI,

KP 1

28 10

2820

2810 Photon energyleV

2820

Figure 4 KP emission spectra of C1- ion in Group I1 and Group I metal chlorides alkali-metal chlorides, shown for comparison in Figure 4. This probably relates with the amounts of ionic character of the bond of these chlorides, because the bond is largely ionic and the valence band arises from the 3p state of the Cl- ion. For alkali-metal, alkaline-earth, and transition-metal chlorides it can be shown that when the difference in electronegativity between metal and chlorine is more than 2.0 and the amount of ionic character is larger than 63%, the KP, band is appreciably narrower, and the sub-band appears to be separated from the KP, band. However, when the difference is smaller than 1.8 and the chlorides are largely covalent, the KP, band is very wide, and the KPx band is ambiguous. Thus the width of the

Elements of Group II

75

KP, band becomes narrow or broad when the bond is largely ionic or ~ovalent.~' The i.r. spectra of the alkaline-earth dihalides MC1, (M = Mg, Ca, Sr, or Ba) trapped in solid Kr matrices at 2 0 K have been determined. From precise measurements of changes in the vibrational modes on isotopic substitution, a linear configuration for MgCl, and CaC1, is confirmed, and an apex angle of 120" is established for the bent molecule SrCl,. For BaC12, the bond angle was estimated at The i.r. spectra of MgX,,MezO (X= C1, Br, or I), MgBr,,2Mez0, and MgBr,n(CD,),O (n = 1 or 2) have been determined from 4000 to 40cm-', and a complete band assignment has been made. Analysis of the data suggested four-co-ordination for Mg and the existence of 0 bridges in the 1: 1 complexes.44 Complexes and reactions of substituted magnesium amides with isobutyric acid esters have been studied. The reaction of Me,CHCO,R (I) ( R = M e or Me3C) with (Me,Si),NMgBr in toluene leads to co-ordination complexes Me,CHC(OR),OMg(Br)N(SiMe,),, which decompose after several hours at ambient temperature or immediately at 60 "C in vacuum. Mixing (I; R = Me) with [(Me,Si),], produced the chelate structure (3), which evolved NH(SiMe,), at 60°C under vacuum to produce (4). The compound (3) can

(3)

(4)

also be prepared from Me CHCOC(MeJC0,Me atld [(Me,Si),N],. The compounds were characterized by hydrolysis and i.r. and n.m.r. ~pectra.~' Addition of magnesium carbonate to aqueous solutions of disodium ethylenediaminetetra-acetate at 25 "C produces the complex salt Na2[Mg(C2H4N2(CH,CO,),],4H,O. Thermal analysis of this complex shows an endothermic process at 140--145"C, corresponding to the loss of the water molecules. At 500 "C, two carboxy-groups are lost ex~thermically.~~ The crystal structure of magnesium ethylenediaminetetra-acetate nonahydrate, Mg,[C,H4N2(CH2C0,),],9H,O, has been determined as orthorhombic, space group Pbcn, with a = 11.622, b = 9.49, c = 19.26 A, d(obs) = 1.595, and d(ca1c) = 1.57 for Z = 4 . The structure is made up of cations 42 43

44 45 46

C. Sugiura, Phys. Rev. (B), 1974, 9, 2679. D. White, G. V. Calder, S. Hample, and D. E. Mann, J . Chem. Phys., 1973, 59, 6645. J. Kress and J. Guillermet, Spectrochim. Actu, 1973, 29A, 1717. L. Lochmann and M. Sorm, Coll. Czech. Chem. Comm., 1973, 38, 3449. V. G. Dudakov and E. B. Shternina, Zhur. neorg. Khim., 1973, 18, 3116.

76

Inorganic Chemistry of the Main -group Elements

[Mg(H20)6]2f and anions [Mg’C2H,N2(CH2C0,),,H,0]2~ with ethylenediaminetetra-acetate acting as a sexidentate ligand. The Mg’ atom is heptaco-ordinated, in a pentagonal bipyramid with two 0 atoms, two N atoms, and an H,O molecule in the equatorial plane and two 0 atoms at the apices. The complex anion is closer to the analogous heptaco-ordinated complexes of iron than of manganese. The complex ions are mutually bound, with hydrogen bonds, into a three-dimensional framework, due to the presence of both water of crystallization and water molecules in the co-ordination sphere of rnagne~ium.~’Disodium magnesium ethylenediaminetetra-acetate tetrahydrate, Na,Mg{C2H,N,(CH2CO2),),4H20, is also orthorhombic, with space group P2,2,2, and a = 13.36, b = 16.52, c = 7.71 A, d(obs) = 1.65, d(ca1c) = 1.69 for 2-=4. This structure is composed of infinite chains of -MgL(H20)-Na2(H20)3(where K L = edta),

Figure 5 Environment of the magnesium atom, with hydrogen-bond lengths (A), in magnesium dichromate hexamethylenetetramine hexahyd rate (Reproduced by permission from Acta Cryst., 1974, B30, 22) 47

A . I. Pozhidaev, T. N . Polynova, M. A. Porai-Koshits, and V. A. Logvinenko, Zhur. strukt. Khim., 1973, 14, 746.

Elements of Group I1

77

with Na-Na distances 3.77 A.48Hexamethylenetetramine (L) reacts with magnesium and alkaline-earth-metal halides MX, (M = Mg, Ca, Sr, or Ba; X = Br or I) to give MgBr,,2L, 10H,O, Mg12,2L,8Hz0, CaBr2,L,6H20, CaBrz,2L,10Hz0, Ca12,2L,8H20, CaI,,4L,12Hz0, SrBr,,2L,8Hz0, SrI,,2L,8Hz0, Sr12,4L,12Hz0, BaBr,,2L,8Hz0, and BaI,,2L,8Hz0.49 Hexamethylenetetramine also forms a complex with magnesium dichrohas been mate. The structure of this complex, MgCr,0,,[(CH2)6N,]2,6Hz0, determined by X-ray diffraction. The crystals are triclinic, space group P i , with a=10.02, b=13.68, c = 9 . 8 1 A , a=96.1", /3=87.9", and Z = 2 . The structure is characterized by two nearly tetrahedral CrO, groups joined through a shared 0 atom, an octahedral [Mg(H,0),I2+ group, and two hexamethylenetetramine molecules linked by hydrogen bonds. The environment of the Mg atom is shown in Figure 5. The magnesium atom is a completely hydrated cation [Mg(H20)6]2' and does not co-ordinate with the dichromate 0 atoms, but the octahedron is slightly distorted. Thus the angles OMgO range from 85.8 to 93.2" and the Mg-0 distances from 2.06 to 2.13A. The mean of the two longer bonds from Mg to 0 - 2 and 0 - 5 is 2.13 A; the mean of the other four is 2.08 A. This is an interesting feature because the six water oxygen atoms are equally bonded to three atoms (the magnesium and two hydrogen atoms) and have no other bond. Usually, the distance Mg-0 is lengthened when the water oxygen atom acts as an acceptor to hydrogen bonds from other Magnesium picolinate dihydrate, Mg(Cs&NC02),,2H,0, crystallizes in the monoclinic system, space group P2,/c, with a = 11.68, b = 8.85, c = 16.00 A, /3 = 115.46", Z = 4. Each of the two picolinate anions (5) are co-ordinated to magnesium through N and

carboxylic 0, and the co-ordination at Mg is made up to six by two water molecules. The octahedron around the cation is distorted, with the metalnon-metal distances shown in Figure 6. The molecule is dihedral, with an angle of 95" between the two pyridine rings, and is hydrogen-bonded to other molecules by the water molecules." The MgKP,,.l X-ray emission spectra from Mg(hfa~)~,2H,O and Mg(aca~)~,2H,O (hfac = hexafluoroacetylacetonate, acac = acetylacetonate) have been determined, The integrated areas of the peaks are in the ratio 1 : 1.3 for these complexes, which indicates that fluorine in the ligand causes a charge withdrawal from 48

49

"

A. I . Pozhidaev, T. N. Polynova, M . A. Porai-Koshits. and V. G. Dudakov, Zhw. strukt. Khirn., 1974, 15, 160. Z . Ysmanova, P. Yun, B. Imanakunov, and A. Karabekov, lzuest. Akad. Nauk Kirg. S.S.R., 1973, 66. F. Dahan, Acta Cryst., 1974, B30, 22. J. P. Deloume, H. Loiseleur, and G. Thomas, Acta Cryst., 1973, B29, 668.

78

Inorganic Chemistry of the Main -group Elements i

C(3)

n

Figure 6 Co-ordination of magnesium in magnesium picolinate dihydrate. DistanceslA from Mg are 0-1, 0-4, 2.05; 0 - 3 , 2.04; 0-6, 2.06; N-1, 2.19, and N-2, 2.25. (Reproduced by permission from Acta Cryst., 1973, B29, 668) magnesium. In the hfac complex, magnesium is octahedrally co-ordinated by oxygen, and though only one peak is expected in association with the Mg-ligand a-bond formation, two peaks are observed. This is attributed to .rr-bonding. Both ligands have lone pairs on oxygen with u-bonding potential to magnesium and, in addition, certain T-orbitals have the correct symmetry to interact with 3p orbitals on Mg. The observed spectra are assigned as Mg(hfac),,2H20 Mg(acac),,2H20

1292 eV 1297 eV 1292 eV

ligand-Mg bond (a) ligand .rr3-Mg 3 p bond ( T ) H,O-Mg bond (a)

1294 eV

ligand-Mg bond (a)

1297 eV

ligand-Mg bond ( r )

Kinetic data as a function of temperature have been reported over the range 5-35 "C for the reactions of Mg2+with ATP4-, ADP3-,and CDP3-. (ATP4-= adenosine 5'-triphosphate, ADP3-= adenosine 5'-diphosphate, and CDP3-= cytidine 5'-diphosphate). The results are compatible with a mechanism involving complexation with the phosphate moiety, the ratedetermining step being the expulsion of a water molecule(s) from the inner hydration sphere of Mg2+.The results are completely consistent with an S,1

'*

D. E. Fenton, C . I. Nicholls, and D. S. Urch, Chem. Phys. Letters, 1973, 23, 211

Elements of Group I1

79

complexation mechanism, and the activation enthalpy is considered to be a more reliable mechanistic criterion than rate constant^.^,

3 Calcium The vapour pressures of calcium and strontium have been determined by a transpiration method at 1126-1300 and 1086-13 10 K, respectively. The temperature dependence of the vapour pressure is given by the equations for Ca, loglo(piatm)= 4.93 - (8550 K/T) for Sr,

loglo(p/atm)= 4.75 - (7720 K/T)

The sublimation enthalpies, AH,"b,for the elements are 43.0 and 39.5 kcal mol-' at 298 K for calcium and strontium, respectively .', The intermetallic phase Ch.05Lil.05Sn has been prepared by melting the elements in the appropriate proportions for 1h at 900°C under argon and subsequently cooling. The compound crystallizes trigonally, space group P3ml-C;,, with a = 4.94, c = 10.90 A, d(obs) = 3.49, and d(ca1c) = 3.55 for Z = 3 . The structure is a new variation of the CaIn, type, with twodimensional infinite, corrugated hexagonal LiSn networks. Within these networks, the Li or Sn atoms are surrounded by three Sn or Li atoms to give a flat trigonal pyramid, formed by the four atoms, with the pyramid axis vertical to the network plane.55 Crystal data have been obtained for calcium borate chloride, Ca2B03C1. Crystals grown from a CaCl, flux at 800 "C were monoclinic, of space group P2,/c, with a = 3.948, b = 8.692, c = 12.402 A, p = 100.27", d(obs) = 2.76, and d(ca1c) = 2.766 for Z = 4.56Calcium gallium oxide, CaGa,O,, has been prepared by melting CaO and Ga,O, in 1: 1 molar ratio. The compound crystallizes in the space group Cgh-P2/c, with a=7.992, b=8.830, c = 10.585 A, p = 94.72", and Z = 8." A calorimetric determination has been made of the enthalpies of formation of the carbonates CaMg,(CO,), and Mg2(OH),C0,,3H,0, and their energies of formation have been determined. The solution enthalpies in HC1 were combined with existing heat-capacity data to deduce enthalpies and energies of formation at 298K. These are CaMg,(CO,),, 1083, 1004; Mg,(OH),C03,3H,0, 698, 614 kcal mol-', r e s p e ~ t i v e l y The . ~ ~ Ca-Si phase diagram has been investigated by thermal analysis and structural determinations, and the liquidus differs considerably from those of existing phase diagrams. Ca,Si and CaSi melt congruently at 1305 and 1315"C, respectively; CaSi, melts incongruently at 1033 "C, and the m.p. of Ca is given as 53 54

55

'' 57 58

J . L. Banyasz and J. E. Stuehr, J. Amer. Chem. SOC., 1973, 95, 7226. G. De Maria and V. Piacente, J. Chem. Thermodynamics, 1974, 6, 1. W. Mueller and R. Voltz, Z . Naturforsch., 1974, 29b, 163. J. Majling, V. Figusch, J. Corba, and F. Hank, J. Appl. Cryst., 1974, 7, 402. H. J. Deiseroth and H. Miiller-Buschbaum, Z . anorg. Chem., 1973, 402, 201. B. S. Hemingway and R. A. Robie, J . Res. U.S. Geol. Suruey, 1973, 1, 535.

80

Inorganic Chemistry of the Main -group Elements 833 (most values are close to 850) and that of Si as 1408"C.59CaSi loses Ca under vacuum at 740"C, and the decomposition is accelerated with increasing temperature. Pure CaSi, is obtained by maintaining the temperature at 880--1000°C. The thermal decomposition of CaSi in the presence of oxygen at 400--1000°C results in the reaction:

4CaSi + 3 0 , + Ca,SiO,

+ 2 C a 0 + 3Si

With nitrogen, CaSi forms Ca,SiN, below 900"C, with liberation of Si. At 900-1200 "C, pure CaSiN, is obtained.60 Measurements of the electrical resistivity of high-purity silicides and germanides from 20 to 800°C show that CaSi,, CaGe,, and SrSi, are metallic conductors whereas BaSi,, BaGe,, and SrGe, possess semiconducting properties. The difference can be attributed to differently structured anion sublattices and different interatomic distances in the metal sublattices.61 The reaction of CaO with SiO at high temperatures has been studied. At 1450-1680 "C, the compounds CaSi, and 2Ca0,Si02 are formed. The process is complicated by the further reaction of SiO with 2CaO,SiO, to produce Ca0,Si02.6' A diffractometric study has been made of the high-temperature transformations of calcium germanates. The compound 3Ca0,GeO has the following structures: at 25 "C, triclinic, space group C1, a = 12.427, b = 7.235, c = 25.44 A, a = 89.83", p = 89.73", y = 89.78"; at 820 "C, triclinic, C1, a = 12.547, b = 7.284, c = 25.79 A, a = 89.92", p = 89.90", y = 89.83"; at 1060 "C, slow decomposition occurs to 2Ca0,GeOz; at 1410 "C, hexagonal, space group P3m, a = 7.317, c = 26.134 A. The compound 2Ca0,Ge02 has the following structures: at 25"C, orthorhombic, space group Pcmn, a = 5 . 2 5 , b = 6.815, c = 11.40 A; at 1480 "C, hexagonal, space group P43rnc, a = 5.69, c = 7.42 bi."' The alkaline-earth hexammoniates Ca(NH,), and Sr(NH,), thermally decompose to metal and metal amide. At 40 "C, the thermal decomposition rate constants for Ca(NH,), and Sr(NH,), are 2.512X and 3.715 X IO-'min-', respectively, and at 63°C these increase by 1-2 orders. The respective activation energies of the thermal decompositions are 4 1 and 33 kcal m01-l.~~ The structure has been determined of crystals of calcium gallium nitride, CaGaN, prepared by the reaction: Ca,N, + Ga + iN, + 3CaGaN at temperatures between 800 and 1000°C. The structure is built up of layers of gallium atoms strongly bonded to N atoms (1.863 A).The Ca 5y

" 61 62

b3 64

E. Schuermann, H. Litterscheidt, and P. Fuenders, Arch. Eisenhuettenw., 1974, 45, 367. A. Gourves and J. Land, Compt. rend., 1974, 278, C, 617. J. Evers and A. Weiss, Materials Res. Bull., 1974, 9, 549. G. N. Kozhevnikov, A. G. Vodop'yanov, N. G. Moleva, and A. V. Serebryakova, Izvest. Akad. Nauk S.S.S.R., Metal., 1973, 61. A. I. Boikova and A. 1. Domanskii, Doklady. Akad. Nauk S.S.S.R., 1974, 214, 633. M. M. Tarnorutskii, S. G. Artamonova, and I . S. Filatov, Zhur. neorg. Khirn., 1974, 19, 889.

Elements of Group I1 81 atoms are between the layers and are surrounded by five N atams, as shown in Figure 7. The bond distances Ca-N’ and Ca-N are 2.529 and 2.418 A, respectively. These are similar to those found in ionic nitrides: Ca3N2, 2.46 A; Ca2N, 2.43 A; CallNs, 2.30-2.50 A; and CaGeN,, 2.44 A, and this suggests that calcium is in the ionic form. The compound has been found previously to possess a high electrical conductivity and metallic p r o p e r t i e ~ . ~ ~

Q

Figure 7 Structure of CaGaN (Reproduced by permission from Acta Cryst., 1974, B30, 226)

A new hydrate of calcium nitrate has been identified, P-Ca(N03),,2M,0. The compound crystallizes from a supersaturated aqueous solution in the monoclinic space group C2/c, with lattice parameters a = 7.79, b = 6.88, c = 12.22 A, = 90.0°, d(ca1c) = 2.03 for Z = 4. The Ca2+ion is surrounded by ten 0 atoms.66A new calcium phosphide, Cap,, is reported to form by 65

6h

P. Verdier, P. L’Haridon, M. Manunaye, and R. Marchand, Acta Cryst., 1974, B30, 226. A. Leclaire, Acta Cryst., 1974, B30, 605.

82 Inorganic Chemistry of the Main -group Elements heating Ca and red P in a 3 : 1 ratio in a quartz ampoule at 650 "C. The black Cap, crystals are triclinic, space group P i , with a = 5.590, b = 5.618, c = 5.66 A, CY = 69.96", p = 79.49", y = 74.78", and 2 = 2.67Recent progress in the chemistry of calcium phosphates, especially apatites, their composition, structure, and properties have been reviewed.68369 The compounds Ca,Sb and Ca,Bi have been prepared by heating the stoicheiornetric amounts of the elements at 1350°C under argon followed by slow cooling. The compounds crystallize tetragonally in the space group 14/rnrnm, with a = 4.67, 4.72, c = 16.28, 16.54 A, d (calc) = 3.76, 5.2, respectively, and Z = 4 . The Sb and Bi atoms are co-ordinated to nine Ca atoms only, to form a distorted tetragonal antiprism, above the plane of which another Ca atom is located as shown in Figure 8.70A more complicated structure is

Figure 8 Unit cell of Ca,Sb and Ca,Bi (Reproduced by permission from Z . Naturforsch., 1974, 29b, 13) adopted by Ca,Bi,. This compound is prepared by cooling a melt of stoicheiometry 3Ca+ Sb with a small excess of Ca from 1150 "C to ambient temperatures under argon. Single crystals are obtained by leaching with liquid ammonia. These are orthorhombic, space group Pnrna, with a = 12.502, b = 9.512, c = 8.287 A, d(ca1c) = 3.81 for 2 = 4. There are four W. Dahlmann, and H. G. Von Schnering, Naturwiss., 1973, 60, 518 T. Kanazawa and H. Monma, Kagaku No Ryoiki, 1973, 27, 662. T. Kanazawa and H. Monma, Kagaku No Ryoiki, 1973, 27, 752. '' B. Eisenmann and H. Schaefer, 2. Naturforsch., 1974, 29b, 13. 67 6H

69

Elements of Group I1

83

crystallographically different Ca atoms, and the structure is built up of layers perpendicular to the b direction of the unit cell. Ca-Sb distances range from 3.249 to 3.371 A and Ca-Ca distances from 3.743 to 4.047 A. The interatomic distances indicate partial ionic character of the bonds." The analogous compound of Bi is Ca5Bi,, which is isomorphous with Ca,Sb,, having a = 12.722, b = 9.666, c = 8.432 A, d(ca1c) = 5.298 for Z = 4. Two compounds were originally found in the Ca-Bi system, viz. Ca,Bi, and CaBi,. The stoicheiometry of Ca,Bi, was later revised to Ca,Bi,. The present work decides that this is more appropriately designated Ca5Bi,. The structure contains two kinds of Bi atoms; a ChBi unit, similar to the CaSb unit found in Ca,Sb,, with Ca-Sb distances 3.423 A, and a CasBi unit, also like that of Ca,Sb in Ca,Sb,, with Ca-Sb distances 3.263 A.72 The deposition of alkaline-earth-metal atoms and ozone molecules at high dilution in argon at 15 K yields species showing intense bands in the i.r. at 800 and 450--650cm-'. Those at SOOcm-' showed the appropriate isotopic shifts for assignment of v3 for the ozonide ion, 0;. The use of scrambled isotopic ozones indicates that the metal cation is symmetrically bound to the ozonide ion, which contains three 0 atoms, with two of these equivalent. In addition, calcium and barium mixtures with ozone contain several metal oxide species tentatively identified as (CaO),, CaO,,BaO, and (BaO),, re~pectively.'~ The formation of alkali-metal and alkaline-earth-metal sulphides and polysulphides from the elements in liquid ammonia has been extensively studied in the past, but the reactions between the metals and hydrogen sulphide in liquid ammonia have drawn detailed attention only recently. It has been suggested that the equilibrium of H,S in this solvent to give the solvated hydrosulphide ion accounts for the formation of KSH even with an excess of metal. With the alkaline-earth metals, effective preparative methods have been developed for the sulphides from H,S in liquid ammonia but anhydrous hydrosulphides have not been obtained. Now, hydrosulphides have been prepared of the form M(SH),,xNH, (M = Ca, Sr, or Ba; x = 4, 6, or 0, respectively) from the metals with H,S in ammonia, but the compounds are stable only at low temperatures. Those of Ca and Sr are stable at -45 "C but decompose to the monosulphides at room temperature. Ba(HS), decomposes to Bas at 100 "C with evolution of a mole of H,S. For M'(SH) (M' = Rb or Cs), thermal decomposition gives polysulphides. The hydrosulphides of Rb, Cs, Sr, and Ba hydrolyse rapidly in moist air.74 Calcium carbonate reacts with low concentrations of SO, in a nitrogen stream at 500 "C initially to form an intermediate product CaS03 and CO,. Subsequently, CaSO, is converted by SO, into CaS0, and sulphur. The formation of CaS is attributed to the reaction of sulphur with CaO liberated 71

M. Martinez-Ripoll and G. Brauer, Actu Cryst., 1974, B30, 1083. A. Haase, and G. Brauer, Actu Cryst., 1974, B30, 2004. D. M. Thomas and L. Andrews, J. Mol. Spectroscopy, 1974, 50, 220. J. A . Kaeser, J. Tanaka, J. C. Douglas, and R. D. Hill, Inorg. Chem., 1973, 12, 3019.

'' M. Martinez-Ripoll, 73 74

Inorganic Chemistry of the Main -group Elements 84 in the thermal decomposition of CaC03.75Alkaline-earth-metal chlorosulphates have been prepared by the reaction of HS0,Cl with-MCl, (M = Ca, Sr, or Ba). The compounds Ca(SO,Cl),, Sr(SO,C1),,2HSO,Cl, and BaS03C1nHSO, (n = 1, 2, or 3) have been characterized by X-ray diffraction, i.r. spectra, and thermogravimetry. The salts decompose thermally to give a mixture of products, consistent with two Ba(SO,Cl),

+ BaSO,

Ba(SO,Cl),

+ BaCl,

+ SO,CI,

+ 2S0,

The reactions of fluorine with aqueous solutions of alkaline-earth-metal chlorides give different products depending on the Group I1 metal. With MCl, (M = Ca, Sr, or Mg), fluorination leads directly to MF,, but with BaC1, the compound BaF(HF,) is formed. An intermediate step in the reaction involves the formation of BaClF followed by substitution of C1- by HF;." Chelate compounds of calcium, Ca(bn), (Hbn = N-benzoylphenylhydroxylamine) and Ca(zm), (Hzm = N-cinnamoylhydroxylamine), have been prepared by warming ethanolic solutions of the organic ligand and metal salt at pH 11.5 to 50 "C. 1.r. and spectral data indicate that the calcium chelates are inner-sphere complexes analogous to the copper chelates, and are weak electrolyte^.^^ The structure of a-galactose-calcium bromide trihydrate has been determined from X-ray diffraction data. The complex has formula C6HI2O6,CaBr,,3H20 and structural formula (6). Crystals are orthorhombic, space

1'1 6H CaBr, 3H,O

(6)

group P2,2,2,, with a = 19.388, b = 8.746, and c = 8.672 A. An outstanding feature of the structure is the interaction of galactose molecules with Ca2+ ions that are co-ordinated to five hydroxy-groups; 0 - 1 and 0 - 2 , 0 - 3 and 0 - 4 , and 0-6, respectively, from three galactose molecules. The coordination by oxygen is made up to eight by further co-ordination to three water molecules, W(1), W(2), and W(3), as shown in Figure 9. The eight 0 75

7h 77

7s

J . Tarradellas and L. Bonnetain, Bull. Soc. chirn. Frunce, 1973. 1903. Ci. Mairesse, P. Barbier, and J. Huebel, Bull. SOC. chim. France, 1974, 1297. F. Chatelut and C. Eyraud, Bull. SOC. chim. France, 1973, 2646. A. T. Pilipenko, L. L. Shevchenko, R. I. Sukhomlin, V. L. Ryzhenko, and M. S. Ostrovskaya, Zhur. obshchei Khim., 1974, 44, 997.

85

Elements of Group 11

Figure 9 Environment of the calcium ion in the hydrated galactose-calcium bromide complex (Reproduced by permission from J. Arner. Chem. SOC., 1973, 95, 6442) atoms form a distorted square-antiprismatic shell round the Ca2+ion, with the Ca-0 distances W(l) 2.390; W(2) 2.352; W(3) 2.446; 0 - 1 = 0 - 3 , 2.495; 0 - 2 , 2.504; 0 - 4 , 2.552, and 0 - 5 , 2.460A. The closest Ca-Br contact is 4.5A, which is 1.5A longer than the sum of the bromide and calcium ionic radii.79 The crystal structures of his@ -D-fructopyranose)-calcium chloride trihydrate, 2C,H,,O,,CaClZ,3H,O, and p-' D-fructopyranose-calcium chloride dihydrate have been determined from X-ray diffraction data on single crystals. The compounds possess space group Cz, P21, with a = 16.631, 7.85, b = 7.847, 11.68, c = 10.886, 7.07 A, p= 127.8, 94.5", d(obs) = 1.61, 1.65, d(ca1c) = 1.61, 1.68 for 2 = 2, respectively. In the former, carbohydrate chains are separated by sheets of Ca, C1, and HzO entities. In the latter, co-ordination around Ca is by seven 0 atoms in a pentagonal bipyramid. Hydroxy-groups of fructose occupy the equatorial positions and water molecules are at the The structure of myo-inositol-calcium bromide pentahydrate, C,Hl,0,,CaBr,,5Hz0, is triclinic, with space group P i and lattice parameters a = 7.513, b = 8.280, c = 15.035 A, a = 70.43", p = 82.06", y = 68.08", d(obs) = 1.90, d(ca1c) = 1.910 for 2 = 2. The structural formula for the compound is shown in (7). H

OH

OH OH CaBr, SH,O (7) 79 80

81

W. J. Cook and C. E. Bugg, J. Amer. Chem. SOC., 1973, 95, 6442. D. C . Craig, N. C. Stephenson, and J. D. Stevens, Cryst. Struct. Comm., 1974, 3, 195. D. C . Craig, N. C. Stephenson, and J. D. Stevens, C r y s t . Struct. Comm., 1974, 3, 277.

86 Inorganic Chemistry of the Main -group Elements The calcium ion is bound to four water molecules and two symmetryrelated myo-inositol molecules, as shown in Figure 10. O n e myo-inositol molecule is attached through its 0 - 2 and 0 - 3 hydroxy-groups, and the second is co-ordinated through its 0 - 5 and 0-6 hydroxy-groups. Together with the water molecules W(2), W(3), W(4), and W(5), these constitute a

Figure 10 Environment of the calcium ion in myo-inositol-calcium bromide pentahydrate (Reproduced by permission from Acta Cryst., 1973, B29, 2404) distorted square antiprism about the Ca2’ ion at distances apart of: 0-2, 2.502; 0 - 3 , 2.459; 0 - 5 , 2.480; 0-6, 2.520; W(2), 2.416; W(3), 2.370; W(4), 2.410, and W(5), 2.439 A. The Ca-0 distances and co-ordination of the metal are in agreement with those found for other sugar-calcium halide complexes and several calcium salts of sugar acids. T h e Br- ions are hydrogen-bonded t o H 2 0 molecules and to hydroxy-groups. There are no direct Ca-Br contacts (the shortest Ca-Br distance is 4.5 A) but several HzO molecules form bridges between the calcium and bromide ions.” Alkaline-earth-metal iodides also form complexes with dimethyl sulphoxide. The complexes Ca12,7Me2S0,Sr12,2Me2S0, and Ba12,8Me2S0 were isolated from solutions of the alkaline-earth-metal iodides in DMSO. The i.r. data bond, attributed to co-ordination of indicate the presence of a M-0 Me,SO to the 4 Strontium

The Sr-A1 phase diagram has been investigated and the vapour pressures of the compounds SrA1, and SrA1, which occur in the system have been determined by the Knudsen effusion method. The phase diagram shows two

’’ W. J. Cook and C. E. Bugg, Hi

Acta Cryst., 1973, B29, 2404. E. Ya. Gorenbein and T. D. Zaika, Zhur. neorg. Khim., 1973, 18, 2279.

Elements of Group I1

87

eutectics, one between A1 and SrA1, at 630 "C and 3.2 mol YO Sr, and one between Sr and SrAl, at 560 "C and 70 mol YO Sr.84Phase relationships in the Sr and Hg system have been studied by thermal and X-ray methods. The compounds SrHg and SrHg, melt congruently at 850 and 772 "C. Eight other compounds form by peritectic reactions: Sr,Hg, 458; Sr,Hg, 478, Sr,Hg,, 545; SrHg,, 512; SrHg36, 481; Sr,Hg,, ca. 427; SrHg,,, 289; and SrHg, (x = ca. 13,62 "C. Eutectics occur at 82.0 moi OO/ Sr (442 "C)and at 40.5 mol%- Sr (694°C). The crystal structures of all the compounds except Sr,Hg and SrHg, have been determined.85 A new hydrated crystalline strontium tetragermanate, SrGe409,2H20,has been isolated from the SrO-Ge0,-H,O system at 25 "C in addition to the known SrH,GeO,. The X-ray pattern of SrGe40,,2H,0 is similar to that of SrGe,O,, previously prepared from SrCO, and Ge02.86 The azides Sr(N,),,6H20 and Sr(N,),,4H20 can be prepared by crystallization from saturated aqueous solutions at -9 and 9 "C, respectively. These compounds are monoclinic, with a = 6.236, 6.355; b = 6.087, 6.196; c = 6.236, 6.355 A; p = 115.12, 119.15"; d(obs) = 2.06, 1.97; d(ca1c) = 2.16, 1.96 for 2 = 1, 8, respectively. The X-ray diffraction patterns differ considThe reaction of strontium with nitrogen erably from that of Sr(N3)z,2Hz0.M7 might be expected to result in the formation of Sr,N,, but in such reactions, even up to 900"C, this nitride was not detected. The products found were Sr,N, SrN, and another phase which was considered to be a mixture or solid solution of SrN and Sr,N. This mixture gives ammonia, nitrogen, hydrogen, and hydrazine on hydrolysis.8*The compound Sr,B2N, has been prepared by heating compressed tablets of Sr,N, and BN mixtures in sealed silica tubes at 950°C. The strontium boride nitride reacted with oxygen at 700°C to form Sr,B,O,. These compounds were characterized by i.r. spectra, X-ray diffraction, and chemical analysis. For Sr,B2N4,the absorption bands of the ' polyphosphide SrP, [BN,I3- ions are observed at 1660 and 580 ~ m - ' . ~The crystallizes in the monoclinic space group C2/m, with a = 11.432, b = 7.387, c = 8.561 A, p = 103.45", and Z = 8. The black compound can be prepared by heating the elements in the presence of sulphur for 2 h at 1150 "C. The polyphosphide Ba3PI4is isotypic with Sr3PI4and has space group P2,la, with a = 11.997, b = 12.990, c = 6.516 A, p = 123.40", and

z= 2."O

The reaction of ozone with strontium peroxide prepared in Freon 12 below 0 "C is reported to produce strontium ozonide, Sr(O,),, and strontium superoxide, Sr(Oz)z.The ozonide forms only below -70°C and neither 84

86 87

" 89

yo

B. P. Burylev, A. V. Vakhobov, and T. D. Dzhuraev, Doklady Akad. Nauk. Tadzh. S.S.R., 1974, 17, 35. G. Bruzzone and F. Merlo, J, Less-Common Metals, 1974. 35, 153. E. A. Knyazev, A. N. Akulov, and A. G. Tarasenko, Zhur. neorg. Khim., 1973, 18, 3146. H. Krischner and H. E. Roth, 2. Krist., 1973, 137, 311. J. Gaude and J. Lang, Rev. Chim. minbrale, 1972, 9, 799. J. Gaude and J. Lang, Rev. Chim. mine'rale, 1974, 11, 80. W.Dahlmann and H. G. Von Schnering, Naturwiss., 1973, 60, 429.

88

Inorganic Chemistry of the Main -group Elements

compound appears above -20 0C.91The electron affinities of SrSe, SrTe, Case, and CaTe have been determined from the temperature dependences of the electrical conductivity and the thermionic emission. By using these values together with previously determined values for BaO, Bas, Base, BaTe, and CaO and a correlation with the lattice spacings, estimates of the electron affinities of other chalcogenides have been obtained by extrapolation. All values are shown in Table 2; extrapolated values are in parenthesis,

Table 2 Electron aflnitiesleV of the Group 11 metal chalcogenides Mg Ca Sr Ba

0 (0.85) 0.70 (0.64) 0.57

S (3.15) (1.85) (1.35) 0.84

Se (4.50) 2.32 1.77 0.9.5

Te -

3.53 2.40 1.43

and MgTe has the wurtzite structure and hence is not included. The electron affinity of a solid is defined as the difference between the surface potential (vacuum level) and the bottom of the conduction band at the surface. The electron affinity of the Group I1 metal chalcogenides decreases as the size of the cation increases from Mg to Ba. This is expected since increasing the size of the cation weakens the strength of the positive ion-negative ion dipole layer at the crystal surface, while increasing the size of the anion strengthens the dipole layer.92 The equilibrium dissociation pressure of strontium sulphate, SrSO,, has been measured by the torsioneffusion method from 1370 to 1540 K. The total pressure for the reaction:

The enthalpy and entropy of vaporization are 127.4 kcal mol-1 and 5 8.5 e.u., re~pectively.~~ The molecular structure of the triethanolamine complex of strontium nitrate, [N(CH,CH20H),]2Sr(N03)2,has been determined by single-crystal X-ray diffraction. In this compound strontium is co-ordinated by the eight heteroatoms of the two triethanolamine ligands in an approximately cubic polyhedron. This is shown in Figure 11. The strontium ion is isolated from the nitrate ions by this cage of six oxygen atoms at Sr-0 distances ranging from 2.534 to 2.594 A, and two N atoms at Sr-N distances 2.830 A. The nitrate ions are linked with the OH groups of the triethanolamine ligands by strong hydrogen bonds. Crystals are monoclinic, space group C 2 / c , with a = 17.972, b = 8.662, c = 14.112 A, p = 104.5", and Z = 4.94The systems 91

92

91 94

I. I. Vol'nov, S. A. Tokareva, G. P. Pilipenko, V. 1. Klimanov, and V. N. Belevskii, Izuest. Akad. Nauk S.S.S.R., Ser. khim., 1973, 2183. K. V. Tsou and E. B. Hensley, J. Appl. Phys., 1974, 45, 47. L. M. Fuke, Report 1973, LBL-1832. J . C. Voegele, J. Fischer, and R. Weiss, Acta Cryst., 1974, B30, 66.

89

Elements of Group I1

Figure 11 Co-ordination of Sr in the triethanolamine complex of strontium nitrate (Reproduced by permission from Acta Cryst., 1974, B30, 66) Sr(BW),-LiBH,-THF and Ba(BH,),-LiBK-THF have been studied at 20°C. In the first system the phase Sr(BH4),,2THF was detected. Both Ba(BW),,2THF and Ba(BH,),,THF complexes were found in the second system.95 5 Barium

The vapour pressure of metallic barium has been determined, and over the temperature range 983-1408 K is given by log(P/Torr)= 7219- (8.025 K/T) 95

V. I. Mikheeva, L. N. Tolmacheva, and A: S. Sizareva, Zhur. neorg. Khim., 1974,19, 1140.

90

Inorganic Chemistry of the Main -group Elements

Using these data and the third law of thermodynamics, the enthalpy of sublimation of barium at 0 K is calculated to be 42 kcal m01-l.~~ The partial and integral molar enthalpies of formation of liquid solutions of Ba and Si have been derived. At 1723°C the enthalpies of formation of the liquid compounds BaSi, BaSi,, and BaSi, are 48.9, 51.2, and 46.0 kJ mol-', respectively." Crystals of Ba,Ge are prepared from the elements at 1200 "C. These are orthorhombic, space group Pnma-D:;, with a = 8.38, b = 5.48, c = 10.04 and Z = 4. The structure is of the anti-PbC1, type.98 The compound Ba,Bi crystallizes in the space group I4/mmm, with a = 5.263, c = 18.700 A, d(ca1c) = 6.20 for Z = 4. These data agree with previously reported results. The compound is isomorphous with Sr,Sb, (see these Reports, Vol. 2, p. 93), and consists of layers of Ba(l), layers of Ba(2), and Bi atoms, forming a close-packed sheet. The Ba(1) atoms have twelve neighbours, 4Bi, 4Ba(l), and 4Ba(2), at distances of 3.668, 3.772, and 4.173 A, respectively. The Ba(2) atoms have nine neighbours, lBi, 4Bi, and 4Ba(l) atoms, at 3.556, 3.784, and 4.173 respectively. Each Bi atom is surrounded by nine barium atoms, forming the unit BiBa,, similar to the SbSr, units in Sr,Sb. The Ba(1)-Ba(1) distance of 3.722A is shorter than the minimum distance of 4.34 A in metallic barium and probably indicates some ionic character of the Structural data have been obtained for the compounds BaMg2M2(M = Si, Ge, Sn, or Pb). These compounds were prepared from the elements. The space groups of BaMg,Si, and BaMg,Ge, are I4/mmm-D;; and those of BaMg,Sn, and BaMg,Pb, are P4/nmm-D:;. For X=Si, Ge, Sn, and Pb, a = 4 . 6 5 , 4.67, 4.89, 5.00; c = 11.09, 11.33, 24.20, 12.11 A;d(expt)=3.27, 4.35, 4.90, 6.60; d(calc)=3.36, 4.45, 4.88, and 6.59, respectively. BaMg,Sn, has Z = 4 ; the other compounds have Z = 2 . BaMg,Si, and BaMgzGezcrystallize with the ThCr,Si,-type of structure whereas BaMg,Sn, and BaMg,Pb, show two new atomic arrangements which are layer variants of this structure."" Barium tetrahydroborate, Ba(BH,),, has been synthesized by the exchange reaction of Bar, with excess LiBH, in THF. The compound is precipitated by addition of ether and melts at 385 "C with little decomposition.'" In studies of alkaline-earth oxogallates and oxothallates, it has been found that the differences between the sub- and super-structure of BaGa,O, concern connections of the GaO, tetrahedra and distortions of the oxygen polyhedra around Ba, and that Ba,T1,0, has space group D:E-Pcmn, with

A,

A,

96

M. P. Parshina and P. V. Kovtunenko, Zhur. fiz. Khim., 1974, 48, 483. Yu. 0. Esin, V. M. Sandakov, P. V. Gel'd, M. A. Ryss, A. K. Golev, and V. P. Zaiko. Zhur. priklad. Khim., 1973, 46, 2402. '* K. Turban and H. Schaefer, Z . Naturforsch., 1973, 28b, 220. 99 M. Martinez-Ripoll, A. Haase, and G. Brauer, Acta Cryst., 1974, B30, 2203. InnB. Eisenmann and H. Schaefer, Z . anorg. Chem., 1974, 403, 163. ''I V. 1. Mikheeva and I. N. Tolmacheva, Zhur. neorg. Khim., 1974, 19, 1222. 97

Elements of Group I1

91

a = 6.264, b = 17.258, and c = 6.05 A. Ba,Tl,O, is isotypic with Ca,Fez05.102*103 The high-temperature crystal structure of barium silicate, BaSi,O,,, has been determined by X-ray methods. At high temperatures the compound crystallizes monoclinically, with space group C2/c, a = 23.202, b = 4.661, c = 13.614 A, p = 97.54", and Z = 6. The structure contains Si,O,, double layers, as in the low-temperature modification, but there is a slightly smaller degree of corrugation of these layers due to the increase in effective ion size caused by extended thermal motion. There are two crystallographically non-equivalent Ba2' ions in the structure which are surrounded by 8 + 2 and 9 + 1 oxygen atoms, re~pecfively.'~~ Crystals of barium thiosilicate, BaSiS,, are orthorhombic, space group Pnma, with a = 8 . 9 3 , b=6.78, and c = 12.01 A.105 The thermal degradation of barium azide under a liquid organic phase is reported to result in the formation of barium pernitride. The exact composition of this decomposition product could not be determined but the compound was either non-stoicheiometric Ba,N, or a mixture of this with Ba3Nz. Contrary to earlier reports, the hydrocarbon medium is seriously degraded, resulting in the formation of BaH, and Ba(HC2),.lo6Hydrated barium azide, Ba(N3),,Hz0,is monoclinic, with space group Cc-C:, a = 7.29, b = 10.84, c = 6.96 A, p = 104"42', and Z = 4. Each Ba atom is surrounded by seven terminal N atoms and two water molecules in the form of a distorted triangular prism, with three more atoms above the centres of each of three faces of the prism. The azide ions are linear and symmetrical, with average N-N distance 1.173 &Io7 The structures of the polysulphides Bas,, Bas2, SrS,, and SrS, have been investigated. The reaction of Bas with S at 550°C produces Bas3 single crystals of space group P42,m, with a = 6.881, c = 4.177 A, and Z = 2. The reaction of Sr(OH), with S at 200 "C under nitrogen produces orthorhombic SrS, prisms of space group B2cb, with a = 7.088, b = 0.982, c = 8.032 A, and Z = 4 . The thermal decomposition of Bas, at 600°C produces monoclinic Bas,, of space group C2/c, with a = 9 . 3 4 7 , b=4.761, c=9.O5OA, p = 118.41", and Z = 4 . Thermal decomposition of SrS, at 300°C produces tetragonal SrS,, of space group 14/mcm, with a = 6.098, c = 7.646 A, and z= 4.108 The structures of a series of barium compounds Ba,CdS,, Ba,CdSe,, BaCdS,, BaCu,S, and BaCu,Se, have been determined in which barium is seven-co-ordinate. Ba2CdS, and Ba,CdSe, are isostructural, space group Pnma, and Z = 4 with a = 8.915, b = 4.336, c = 17.244 A for the former

'04

H. J. Deiseroth and H. Muller-Buschbaum, 1 Inorg. Nuclear Chem., 1973, 35, 3177 R. Von Schenck and H. Muller-Buschbaum, 2.nnorg. Chem., 1974, 405, 197. H. Katscher, G. Bissert, and F. Liebau, Z . Krist., 1973, 137, 146, J. T. Lemley, Acta Cryst., 1974, B30, 549. S. Salot and J. C. Warf, Inorg. Chem., 1974, 13, 1776. E. M. Walitzi and H. Krischner, Z . Krist., 1973, 137, 368. H.G . Von Schnering and Ngoh-Khang Goh, Naturwiss., 1974, 61, 272.

92

Inorganic Chemistry of the Main-group Elements compound and a = 9.225, b = 4.482, and c = 17.871 8, for the latter. These compounds are also isostructural with the previously reported Mn analogues and with K,AgI,. Cadmium ions are in a tetrahedral environment and the tetrahedra form infinite linear chains by corner sharing. The Ba2+ions are in seven-fold co-ordination in which six anions form a trigonal prism and one anion caps one of the rectangular faces. This geometry persists in the compound BaCdS,, which has space group Pnma, a = 7.278, b = 4.167, c = 13.919 A, 2 = 4,and which is isostructural with BaCdO,. The analogous BaCdSe, could not be prepared. Barium ions are in the usual seven-fold, capped hexagonal prism, co-ordination in BaCu,S2 and BaCu2Se,, which are also isostructural, with space group Pnma, Z = 4, and a = 9.308, b = 4.061, c = 10.408 A for the sulphide and a = 9.594, b = 4.214, c = 10.775 8, for the selenide. However, nine Cu ions can also be considered to form a trigonal prism, with all rectangular faces capped, around Ba, since Ba-Cu distances range from 3.24 to 3.54 8, for the sulphide and from 3.37 to 3.67 8, for the selenide.lo9 A study of the system BaC1,-MeOH-Ba(OMe), has revealed two compounds, Ba(OMe),,MeOH and ClBaOMe, the latter separating from solution as large blue crystals.ll" The crystal structure of barium oxalate monohydrate has been determined. The compound BaC204,Hz0is monoclinic with space group C2/rn, a = 10.10, b = 7.96, c = 6.83 A, p = 121"58', d(obs) = 3.40, and d(ca1c) = 3.43 for 2 = 4.l" The compounds Ba(MeCOS)3,3H,0 and M(MeCOS)(MeCO,),xH,O (M = Ca, x = 3; M = Sr, x = 4) have been prepared by the reaction of MeCOSH with the alkaline-earth carbonates in aqueous solution. The metal acetate thioacetates M(MeCOS)(MeCO,),xH,O crystallized in the monoclinic system. For M = Ca, a = 6.75, b = 15.44, c = 11.34 A, = 113"14', d(obs) = 1.44, d(ca1c) = 1.4 for Z = 4. For M = Sr, a = 12.72, b = 7.095, c = 12.97 A, p = 111"8', d(obs) = 1.86, d(ca1c) = 1.78 for Z = 4. The thermal decomposition of these compounds under nitrogen is as follows: Ba(TAc),,3H20 SrAcTAc,4H20

-

Ba(TAc),,H,O

-

SrAcTAc, 1SH,O

Bas

Ba(TAc),

a SrAcTAc,H,O 180°C

.L

mSr(Ac),( 1- m)SrS

SrAcTAc

I

480 "C

mSrCO,(l- m)SrS log 110

111

J . E. Iglesias, K . E. Pachali, and H. Steinfink, J. Solid State Chem., 1974, 9, 6. E. P. Turevskaya, N. Ya. Turova, and A . V. Novoselova. Doklady Akad. Nauk S.S.S.R., 1973, 212, 1346. J. C. Mutin, A . Aubry, G. Bertrand, E. Joly, and J. Protas. Compt. rend., 1974, 278, C, 1001.

Elements of Group I1 CaAcTAc73H,0

CaAcTAc,H,O

-

93

CaAcTAc,OSH,O

I

1R O T

(1 - rn)CaSrnCa(Ac),

a CaAcTAc

450'C

where Ac = CH,CO; and TAc = CH,COS-.l12 The structure of barium 2-0sulphonato-L-ascorbate dihydrate, Ba(C6H609S),2H20, has been determined from three-dimensional X-ray diffraction data. This sulphate derivative of ascorbic acid (vitamin C) crystallizes in a triclinic cell, space group P1. Cell parameters are a = 5.201, b = 6.951, c = 8.732 A, a = 99.54", 0 = 93.29", and y=lO9", d(obs)=2.44, d(calc)=2.43 for Z = 1 . All but two of the oxygen atoms of the anion (8) are engaged in Ba" co-ordination. These are

HO'CHZCHCHCCOSO, OH

0

(8)

marked 0'. One water molecule is co-ordinated twice, so that each Ba2' is surrounded by ten oxygen atoms belonging to three water molecules and three sulphatoascorbate anions. The Ba-0 distances lie between 2.757 and 3.065 The crystal structure of the triethanolamine complex of barium acetate, [N(CH,CH,0H)3]2,Ba(MeC02)z,has been determined. The structure is made up of complex cations, [N(CH2CH,OH),BaO2CMe]', and acetate ions, MeCO;. As in the triethanolamine complex of Sr(N0,)2 mentioned above, the alkaline-earth-metal atom is held in a cage comprising the eight oxygen and nitrogen heteroatoms of the two tripod ligands (9) but

,,.& & O' c 3( L

O

C6

0'3

3

C '6

(9) 'I2 '13

M. A. Bernard, M. M. Borel, and M. A. Ledesert, Bull SOC. chim. France, 1973, 2194. B. W. McClelland, Acta Cryst., 1974, B30, 178.

94

Inorganic Chemistry of the Main -group Elements OA 1

N

N'

Figure 12 The environment of Ba in the triethanolamine complex of barium acetate (Reproduced by permission from Acta Cryst., 1974, B30, 70) in addition is linked to the O(A1) atom of one of the acetate groups, giving overall nine-co-ordination as shown in Figure 12. Barium-oxygen(1igand) distances range from 2.743 to 2.803& Ba-N distances are 3.025 and distance is 3.108A for N and N', respectively, and the Ba-O(acetate) 2.726 A. The crystals are triclinic, space group Pi, with a = 11.915, b = 10.317, c = 11.223 A, Q = 118.59", p = 98.57", y = 91.98", and Z = 2."" I14

J . C . Boegel, J. C . Thierry, and R. Weiss, Actu Cryst., 1974, B30, 70

3 Elements of Group 111 BY G. DAVIDSON

1 Boron General.-An extensive series of chemical and physical measurements of p -rhombohedra1 boron has been reported (density, lattice constants, microhardness, thermal expansion, electrical resistivity, melting point). The melting point was found to be 2365 K.' The determination of boron in silicon .may be achieved by separating the B by fusion with Na,O,-Na,CO,, followed by conversion of the B into boric acid, which may be determined by potentiometric titration.* A high-resolution n.m.r. spectrometer has been developed for the determination of reliable "B chemical shifts in solids containing tetrahedrally co-ordinated b o r ~ n The . ~ data reported are summarized in Table 1. Table 1 "B chemical shifts for tetrahedrally co-ordinated boron Compound NaBH, KBF, Me,NBCl, [PCI, Br,-,]'BCl, PBr,B Br, Et,NBBr, Et,PBI, Na,B,O,. I OH,O BPO4 BP

S"B/p.p.m. from B(OMe), 64* 1.5 18 11 10* 1 42.3 * 1 52.5 f 1 135.2+0.5 11k.3 32.4* 1 6713

Cragg and Weston have written an extensive review of the mass spectra j f boron compounds of all types." A report has been made of "B and '"N n.m.r. data for a wide range of B-N compounds containing four-co-ordinate b o r ~ n Similar .~ data have also been given for B-N, B-C, B-0, and B-S compounds with three-co-ordinate boron.6

'

C. E. Holcombe. D. D. Smith, J . D. Lore. W. K. Duerksen. a n d D. A. Carpenter, High Temp. Sci.. 1973, 5, 349. ' M. Taddia and M. 7'. Lipolis, Ann. Chim. (Italy), 1973. 63, 131. ' K. B. Dillon and T. C. Waddington, Spectrochim. Acta, 1974, 30A, 1873. R. H.Cragg and A. F. Weston, J. Organometallic Chem., 1974, 67, 161. N. Niith and B. Wrackrneyer, Chem. Ber.. 1974, 107, 3070. H. Noth and B. Wrackrncyer, Chem. Ber., 1974, 107, 3089.

95

96 Inorganic Chemistry of the Main-group Elements In a long and thorough review of the photoelectron spectra of a large number of non-metal compounds, attention is drawn to their ready interpretation by MO models. Topics such as electron-deficiency (of particular interest in the context of boron compounds), 0-and .rr-interaction, and electron-pair delocalization are also considered.'

Boranes.-Ab initio MO calculations, using a restricted Hartree-Fock scheme, on the postulated radical HBF yield values for the optimal geometry which depend upon the nature of the gaussian basis sets.' Three possibilities are: r(H-B) = 2.60 a.u., r(B-F) = 2.45 a.u., L H B F = 122"; 2.53, 2.61, 121"; or 2.25, 2.50, 121". SCF calculations of the MO's in the system: 2BH, F B,H, suggest that a symmetric (C,,,) approach of two BH, units is preferred to an unsymmetric ( C , ) one, with formation of only one H-bridge. The transition state has been calculated to be 2.6 kcal mol-' (of B&) higher than 2BH3, with two equivalent unsymmetrical B - .H-B bridges (B-B distance 3.0 All four possible borane adducts of hexamethylenetetramine have been isolated: (CH,),N,,nBH, ( n = 1, 2, 3 or 4).'" Some i.r. and n.m.r. spectral data have been listed for all of them. An ab initio MO calculation has been carried out on B,H,." If it is regarded as being an interacting system of two BH, units, the charge density in the region between these could be calculated within the framework of configuration analysis. The charge-transfer interaction was found to be the most significant for the proper description of the bridged three-centre bonds in B,H,. The Raman spectrum of B,H, has yielded values for the u = O + 2, 1 -+ 3, and 2 + 4 ring-puckering vibrational transitions at 753.7, 776.1, and 795.6 cm-', respectively (for 'lB2H6)." The thermal decomposition of B,H, was found to have a reaction order of 3/2 in diborane concentration. The Arrhenius parameters (probably too low) are: *

log(A/cm"* moll'* s-') = 4.72 k0.14 E, = 42.47 f 1.17 kJ mo1-l

The reaction was truly homogeneous, since neither coating nor changes in surface: volume ratio altered the rate ~ 0 n s t a n t . l ~

'

H. Bock and H. CJ. Ramsey, Angew. C h e m . Inmnnt. E d n . , 1973. 12, 731. A. Brotchie and C. Thomson. Chem. Phys. Letters. IY73. 22, 338. 1. M. Pepperberg, and W. N . Lipscomb. J . Anier. C h r m . Soc.. 1974. 96, 1315 M. D. Rilcy and N. E. Miller. Inorg. Chem.. 1974. 13, 7 0 7 . S . Yamabe, '1'. Minato, H . Fujimoto, and K. Fukui, Theor. C h i m . Actu, 1974. 32, 187. L. A. Carreira. J. D. Odom, and J . R. Durig, J. C h e m . Phys., 1973, 59, 4 Y S 5 . [ I . Fernandez. J . Crrotewold. and C. M. Previtali, .I.C'.S. Dalton, 1973, 2090.

' D.

' 11. A. Dixon. I" ' I I' ' I

Elements of Group 111 97 The reaction of 0 atoms with BZH6 may be studied in a discharge-flow reactor using a time-of-flight mass spectrometer as detector.14 In the presence of excess 0 atoms, the rate constant for the disappearance of B&6 is k, = (4.2 k2.7) x lo'' cm3molecule-' s-' at room temperature, with the activation energy 4.8 f0.5 kcal mol-'. If excess B,H6 is present, the reaction is faster, and gives rise to chemiluminescence [from BO, A(2II)+ X(,Z), u ' = s S ] . These data have been interpreted in terms of a chain mechanism:

0 + B2H6 + B H 3 0+ BH,

(initiator)

BH,+O+ OH+BH2 O H + B,H6 + H,O

+ BH, + BH,

I

(propagators)

When 0 atoms are in excess, BZH6 disappearance is controlled by the first reaction, while 0 atoms are removed, thus: O+B,H6+BH,+BH,0 BH,O+ 0 + BH,+ 0, 2FH,

-+

B&

Unlike Me,SO, R 3 P 0 ( R = M e or Ph) causes a symmetrical cleavage of B2H6, producing mainly R3P0,BH3 (characterized by n.m.r.), with some R3P,BH3 by reduction of the oxide. l5 Trimethylamine N-oxide hydrochloride, with NaBH,, produces the analogous Me,NO,BH,. A direct reaction of amine N-oxides with B2H6 gave violently explosive products, and it has been tentatively suggested that these were the products of unsymmetrical cleavage, e. g. [(R,NO),BH,]'BHi. The ring-puckering vibrations of I.L -NH2B2H5,together with the ND2-, B2D5-, and perdeuteriated derivatives, are at 337.6, 333.6, 244.6, and 243 cm-', respectively.16 Field-ion mass spectra have been reported for B4H10, B5H9,Me3N,B3H,, Me,N,BH,, Me3N,BH2Br, and 1,1,4,4-tetrarnethyl- 1,4-diazonia-2,S-diboratacyclohexane. l 7 Least-squares-fitted monoisotopic mass spectra have been tabulated for B4H10, B,H,Br, BSHsI, B,H,,, EtBlOHl,,and B10H16. Isotope cluster analysis of the spectrum said to be due to B,,H,, shows that it is actually a mixture of C,BlOH,, and C,B,H,,.'8 "B, 13C, and 'H n.m.r. spectra of pentaborane, ethylpentaboranes, and "C-enriched methylpentaboranes have been obtained. Analysis of the chemical-shift data yielded values for the effective electronegativities of the boron atoms in the cage structure-these were found to be consistently l4 I'

'' "

'*

C . W. Hand and L. K. Derr, lnorg. Chem., 1974, 13, 339. R. A. Geanangel, J . Inorg. Nucleur Chrm., 1974. 36, 1397. A. S. Gaylord and W. C. Pringle, J. Chem. Phys., 1973, 59, 4674. L. A. Larsen and D. M. Ritter, Inorg. Chem., 1Y74, 13, 2284. E. McLaughlin, L. H. Hall, and R. W. Rozett, J . Phys. Chrm., 1973, 77, 2984.

Inorganic Chemistry of the Main- group Elements

98

lower for the apical than for the equatorial B atoms.', The resultant charge differences are in good agreement with those indicated by recent MO calculations on these systems. The reaction of BMe, with B,H, (catalysed by GaMe,) produces 2MeB,H, via a route that can be regarded as being formally analogous to a carbene-insertion reaction.20Similar boron-insertion reactions using H,BCIOR, with [Me3MTVB,H,]-(MrVSior Ge) produce l-Me,M'"B,H,, which are the first known examples of apically substituted hexaborane(10) derivatives. Pentaborane(9) reacts with primary amines to give adducts B5H9,3NH2R, with breaking of B-H-B bonds." These adducts decompose at ca. 150-1 80 "C, to N-alkylborazines:

B,H,,3NH2R

-

1 HB N ''

+

(BH), + 5H2

BH

R

The crystal structure of B,H,(PMe,); has been determined, and the resulting molecular structure is shown in Figure 1. The molecule is fluxional, and the "B n.m.r. spectrum is consistent with the scheme shown in formulae (la) and (lb)." C6

4

Figure 1 Structure of R,H,(PMe,)2, showing ellipsoids of thermal motion (Reproduced by permission from J . Amer. Chem. SOC.,1974, 96, 301 3 ) T. Oriak a n d E. Wan, J. Magn. Resonance, 1974. 14, 66. D. F. Gainea, S. Hildehrandt. and J . Ulrnan, Inorg. Chem., 1974, 13, 1217. A. F. Zhigach, V T. Laptev. A. B. Petrunin. V . S . Nikitin. and D. H . Bekkcr. R i m . .1. Inorg C h o n . , 1973. 18, 1080. '*A. V. Fratini, G. W. Sullivan, M. L. Denniston. R. K . Hertz, and S. G. Shore, J. Amer. C'hem. S o c . . 1071. 96, 3013. Iy

Elements of Group 111

99

Variable-temperature '€3 and "€3 n.m.r. spectra of B6HI0,2-MeB6H9, and 2-BrB6H9show that the static structures are found in all cases at temperais in agreement with tures between -1 10 and - 150 0C.23That for X-ray data. The others possess structures containing no mirror-plane. Ambient-temperature spectra involve scrambling of all bridging hydrogens, while those at intermediate temperatures are consistent with the scrambling of only some of these. A b initio SCF calculations have yielded wavefunctions for B,H,,, B,H,,, . ~ ~ have been compared with the results of B&&-, BloH:;, and B I o H : ~These an approximate calculation using the PRDDO (partial retention of diatomic differential overlap) method. The latter was found to give quite satisfactory results, for much less computing time. "B n.m.r. chemical shifts for all possible isomers of monochloro-, monobromo-, and monoiodo-decaborane( 14) have been determined using the "B-"B double-resonance technique." The data for 5-chloro- and 6iodo-decaborane(l4) were reported for the first time. All trends in the chemical shifts are dominated by the influence of the 2p orbital size on the paramagnetic shielding term (up). A study of a large number of "B chemical shifts in monohalogenodecaboranes has provided a good basis for the prediction of chemical shifts in the disubstituted compounds. Thus, if A u A and A u B are the A-shifts in the monohalogenodecaboranes, then the A-shift in the related dihalogenodecaborane, Auc, is given by: AuC= (0.920 *0.019)(A~,+ AuB)- (0.047*0.0049)

The relevant chemical shifts were mostly assigned using the "B-"B doubleresonance technique.26 Localized MO's have been derived for B16H20, using Boy's procedure, from the results of a PRDDO calculation, based on the simpler hydrides *' 24 25

26

V. T. Brice, H. D. Johnson jun., and S. G. Shore, J . Amer. Chem. SOC., 1973, 95, 6629. J . H. Hall jun., D. S. Marynick, and W. N . Lipscomb, J . Amer. Chem. Soc., 1974, 96, 770. R. F. Sprecher, B. E. Aufderheide, G. W. Luther tert., and J . C. Carter, J. Amer. Chem. SOC., 1974, 96, 4404. R. F. Sprecher and B. E. Aufderheide, Inorg. Cheq., 1974, 13, 2287.

100

Inorganic Chemistry of the Main-group Elements

BioH14 and B,H,, as analogues. LMO's from smaller molecules can apparently be transferred to closely related regions of larger m01ecules.~~ Pyrolysis of B,H,,S gives three isomeric forms of (B9H8S)2;one was shown by X-ray crystallography to be the 2,2'-(1-B,H,S)2. "B n.m.r. evidence supported the formulation of the others as 2,6'- and 6,6'(BJW)2.28 Borane Anions and Metallo-derivatives.-Greenwood and Ward have reviewed the synthesis and structures of metalloboranes, with a discussion of metal-boron bonding." i n a review of the mechanisms of homogeneous reductions of inorganic species by tetrahydroborates, Hanzlik was able to compare the mechanism of the redox process proper with the homo- and hetero-geneous oxidation of alkali-metal tetrahydroborate~.~~ The "B and 'H n.m.r. spectra of THF solutions containing LiBH, and LiBD, contain signals due to all of the series BH4-,D; (n=O-4).31 There was evidence for an isotope shift in the "B spectrum-thus the resonance due to BH,D- occurs ca. 0.011 p.p.m. upfield from BH;, and J("B-H) in BH3D- is ca. 0.4 Hz less than in BH,. These are the first observations of an isotope shift in "B n.m.r. spectra. A study of the polymorphism of LiBH, to 45 kbar and 550 "C has revealed the existence of five solid forms, and the phase diagram has been pre~ented.~~ Phase relationships in the LiBK-Et,O-PhMe system were studied at 20 "C (three phases were found:. LiBH,, LiBH,,O.SEt,O, and LiBH,,Et,O) and at 85 "C (only LiBH, is p r e ~ e n t ) . ~ ' The energy levels due to hindered rotation of BH; in the hightemperature phases of NaBH, and KBH, have been ~ a l c u l a t e d .The ~~ torsional frequency was calculated to be 240cm-' (NaBH,) and 224cm-' (KBH4). A re-investigation of the electron diffraction of gaseous beryllium borohydride, BeB,H,, is consistent with a linear heavy-atom skeleton rather than a triangular a~rangement.~' One could interpret the data using BeB-B and B-Be-B models, but the latter was considered to be more plausible. The following values for some geometric parameters were proposed: r(Be-B) 1.790(0.015) A, r(B-H,) 1.303(0.012)A, r(B-H,) 1.16(0.04) A, LH,BH, 117.5(1.2)". "

'*

D. A. Dixon, D. A . Kleier. T. A. Halgren, and W . N. I.ipscomb, J. Amer. Chern. SOC.,1974,

96, 2293.

W. R . Pretzer and R. W. Rudolph, J.C.S. Chem. Comm., 1974, 629. N. N. Greenwood and I . M. Ward, Chem. SOC. Reu.. 1974. 3, 231. '"J . Hanzlik, Chrrn. listy, 1973. 67, 1239. " B. D. James. B . E. Smith, and R. H. Newman, J.C.S. Chem. Comm.. 1974, 294. '' C. W. F. T. Pistorius, Z. phys. Chrrn. (Frankfurt), 1974, 88, 253. 71 K. N. Semenenko. B. M. Bulychev, E. A. Lavut, and 1. A. Shapiro, Vestnik. Moskou. Uniu.. Khim., 1973, 662. 7 4 D. Smith, J. Chern. Phys., 1Y74. 60, 958. is G. Gundersen, L. Hedberg, and K . Hedberg, J. Chrrn. Phys., 1973, 59, 3777.

Elements of Group III

101

Ab initio calculations of the energies of Be(BK), for a wide variety of possible configurations suggest that three of these are very similar in energy, and might co-exist in the vapour phase: (2), (3), and (4). This conclusion

(4)

agrees with the observed complexity of the vapour-phase vibrational spectrum of BeB,H8.36 Sr(BH4),,2THF is produced by the reaction of SrCl, with N a B K in THF. Heating to 180 “C yields the non-solvated compound, which is stable to 410°C. It is soluble in THF and diglyme, but not in diethyl ether or di~xan.~’ The reaction of ZnC1, with NaBH, in Et,O solution gives a crystalline compound NaZn(BH&,Et,O. This has been characterized by X-ray studies and elemental anal~sis.’~ A number of complexes of Bfi- and BH,CN- (B) with Co, Ni, Cu, Pd, and Pt have been prepared, e.g. MBL, and MHBL, (L = phosphine; B = BK- or BH,CN-, n = 2, 3, or 4).391.r. spectral data for some of the BH,CNco-ordinations complexes appear to suggest that both M-N and M-H-B occur. The latter gives a u(B-H) band at 2122 cm-’ in Cu(BH,CN)(PPh,). E.s.r. data for the anion B,H;, and a b initio unrestricted Hartree-Fock calculations, both favour an ethane-like structure of D,, symmetry, rather structure, analogous to that of the parent than the bridged, DZh, Tetra-alkylammonium AlH; salts react with diborane in THF to give the B,H; salt and Al(BH,), or a substituted Al(BH4)7.41 The thermal decomposition of NR: B,H, ( R = H , Me, or Et) has been investigated.” When R = H the principal decomposition products are BN, B, and H,, at 98-100 “C;while when R = Me they are BN, B, H,, and C K , and when R = Et they are BN, B, H,, CH4, and C,H, (both at >200 “C). 76

D. S. Marynick and W. N. Lipscomb, J. Amer. Chem. Soc., 1973, 95, 7244. V. I . Mikheeva and L. N. Tolmacheva, Russ. J . Inorg. Chem., 1973, 18, 899. ’’ N. N. Mal’tseva, N. S. Kedrova, and V. I. Mikheeva, Russ. J . Inorg. Chem., 1973,18, 1054. ” D. G. Holah, A. N . Hughes, B. C. Hui, and K . Wright, Canad. J . Chem., 1974, 52, 2990. 40 T. A. Claxton, R. E. Overill, and M. C. R. Symons, Mol. Phys. 1974, 27, 701. 41 L. V. Titov, V. D. Sasnovskaya, and V. Ya. Rosolovskii, Russ. J. Inorg. Chem., 1973, 18, 1.570. 42 I. S. Antonov, M. A. Pchelkina, V. S. Nikitin, G. A. Egorenko, Z . F. Vinogradova, and A . T. Kurakova, Russ. J. Inorg. Chem., 1973, 18, 321. ”

102

Inorganic Chemistry of the Main- group Elements

Evidence has been presented for the B,Hi ion acting as a bidentate or a terdentate ligand in transition-metal complexes. Thus Mn(CO),Br reacts with Me4" B,H, to give Mn(C0)4(B3H,), characterized by "B and 'H n.m.r. spectra as ( 5 ) . Under U.V.irradiation an equilibrium: (OC),MnB3H,

* (OC),MnB,H,+

CO

is set up. The tricarbonyl species apparently has the structure (6).43

oc

\

/

0 c

I

H'

oc

(5)

B,H, reacts with Fe(CO),, and B,H,, with Fe,(CO),, to produce a stable ferraborane, B,H,Fe(CO),, the spectroscopic properties of which suggest that it has the structure (7)."" The reaction of SiF, with ethereal LiB,H, solution at -78 "C gave mainly 2-SiFsBsHs, with about 1% of the 1-isomer. Physical properties and n.m.r. and i.r. spectral data have been reported for the two isomers.45 1- and 2-BrB,H8 form an oxidative addition product with IrCl(C0)(PMeJ,, uiz. 2-[IrBr,(CO)(PMe,),]B5H8, in which the Ir is linked to the B-2 atom. The nature of the product is independent of the stereochemistry of the initial borane. The final complex was characterized by single-crystal 43 44

45

D. F. Gaines and S. J . Hildebrandt, J. Amer. Chern. Soc., 1974, 96, 5574. N . N . Greenwood, C. G. Savory, G. Ferguson, and W. C. Marsh, J.C.S. Chem. Comm., 1974, 718. A. B. Burg, Inorg. Chern., 1974, 13, 1010.

103

Elements of Group 111

X-ray diffraction: the Ir-B(2) distance was 2.07(1) A, while B(1)B(basa1) distances were in the range 1.64(2)-1.69(2) A, and B(basa1)B(basa1) distances were 1.80(2)-1.91(2) The excited states of B6H2-, B,H;-, B,,H:;, B12H:2, B,Cl,, and BlZC1:; have been calculated, including extensive configuration intera~tion.~' The results confirm the original assignments for the electronic spectrum of B4C14, and agree reasonably with that for B,Hi-. The other species appear to have no accessible states in the near-u.v. region. Some new transition-metal complexes of B ~ H Ihave o been prepared,,* e. g. Fe(C0)5+ p-Fe(C0)4-(B6H10)

Fe,(CO),+

I.r., "B n.m.r., and Mossbauer data for this complex support the formulation of this as an Fe" complex with a metal-B4, B, three-centre, twoelectron bond. The complexes ~ ~ ~ ~ S - P ~ ( B ~ H IRh(B6Hl,),(acac), O)ZC~Z, [Rh(B,H,,),Cl],, and [Ir(B6Hlo)C1], are formulated in a similar manner. A stabilized heptaborane system [NBu,]+[p -Fe(CO),-fi,H,,]- has been prepared by the following route:

+NBulI- + [NBu4]+[p-Fe(CO),-B6H,]- + KI [NBu4]+[p -Fe(CO),-B6H9]-+ iB,H6 -+ [NBu4]+[p -Fe(CO),-B,HI2]K+[p-Fe(CO),-B,H,]-

This novel anion has the structure shown in Figure 2 (average B-Fe distance = 2.20 f0.02 A). The action of HCl upon this produces the related Q

Figure 2 The structure of [p -Fe( CO)4-B,Hl,]p (Reproduced from J.C.S. Chem. Comm., 1974, 604) 4h

47 48

M. R. Churchill, J. J . Hackbarth, A. Davigon, D. D . Traficante, and S. S. Wreford, J. Amer. Chem. SOC.,1974, 96, 4041. D. R. Armstrong, P. G. Perkins, and J. J. P. Stewart, J.C.S. Dalton, 1973, 2277. A. Davison, D. D . Traficante, and S. S. Wreford, J. Amer. Chem. SOC., 1974, 96, 2802.

Inorganic Chemistry of the Main-group Elements 104 neutral species F-F~(CO),-B,H,,. The structure of this is not known, but the Fe(CO), group probably occupies a bridge site.,' An analysis of the 70.6MHz "B n.m.r. spectrum of labelled B,H,,Srevealed that a rearrangement occurs during the formation of the thiaborane from B,,H,,, B9H,,,SEt,, or B9H;z.'" Electrochemical oxidations of both apical and equatorial isomers of B,,H,12- and B,,H,L- (L = NH3, NMe,, or SMeJ are analogous to those of the unsubstituted B,,H:; ion, and may be summarized in the following equations:

e BloH,L + e2BloHgL -+ BZoH1,L; + H' B,,H,L

B,oH,,L; C BzoH16Lz+ H'

+ 2e-

The Bz0H,,L~and Bz0H,,L~-(from deprotonation of the former) ions and B,,H16L, compounds are similar in their chemistry to the ions B,,H:,, B,,H:;, and B,,H:;. Equatorial substitution gives primarily inductive effects on the rate of the second equation, while apical substitution can lead to a change in the rate-limiting step under conditions of strong electron withdrawal. 51 Both electrolytic and protolytic methods of decomposition of iodobenzenenonahydro-closo-decaborate(1-), BloH91Ph-, led to the formation Of B ~ o H , I ~ - . ~ ~ Hg(NCS), reacts with 6,9-B,,H1,(SMez)z or 6,9-B10H12(SEt2)2 to give BIOHI3NCS, while this species can also be prepared from NaNCS + B,,,H,,. X-Ray studies show that the structure is as shown in Figure 3. The NCS group is co-ordinated (uia N) to B-6 and the B-N bond distance (1.435 A) is too short for a pure single bond."

Figure 3 The molecular structure and numbering system for B,,H,,NCS (Reproduced by permission from Inorg. Chem., 1973, 12, 2915) 4y

'' " s3

0. Hollander. W. R. Clayton, and S. G. Shore. J.C.S. Chem. Comm., 1974, 604. A. R. Siedle, G. M. Bodner, A. R. Garber, and L. J. Todd, Inorg. Chem., 1974, 13, 1756. A. P. Schmitt and R. L. Middaugh, Inorg. Chem., 1974, 13, 163. R. L . Middaugh, Inorg. Chern., 1974. 13, 744. D.S. Kendall and W. N. Lipscomb, Inorg. Chem., 1973, 12, 2915.

Elements of Group I11

105

A number of new arsaboranes have been prepared from d e ~ a b o r a n e . ~ ~ This reacts with AsCl, in the presence of base and a reducing agent, to give 7-BloHl,As- (the structure proposed on the basis of n.m.r. and other data). This, in turn, yields l,2-BloH1,Asz on further treatment with AsCl,, while the reaction of the latter with piperidine produces 7,8-B9HloAs;. The arsenic atom in the mono-derivative may be quaternized to yield BloH,,AsR, and BloH,, and PhAsC1, react to give BloHllAsPh-. Some new by-products have been isolated from oxidative coupling reactions of BloH:; ‘(which yields chiefly B,,H:;, and B 2 0 H 3 .Thus, the presence of Fe(NO,), gives some B2,H1,NO3-;FeCl, gives 1,6,8-Bl0H7Clf-and 1,6- or 2,6-BloHsC1;.55 A new series of metalloboranes, related structurally to BlOH14, have been bridge reported; they contain B,-ligands bound to metals via two M-H-B bonds and an M-B u -interaction. Their synthesis has been accomplished by treatment of M(CO),Br with K+B9HY4in ethereal solvents (M= Mn or Re), and the following were characterized: 2-THF-6-(CO),-6-MnB,H1,, 5-THF6-(CO),-6-MnB9H,,, 2-Et,0-6-(CO),-6-MnB,H12, and salts of [6-(CO),-6MnB,H,,]- and [6-(C0)3-6-ReBgH,,’]-. The crystal structure of 5-THF-6(CO),-6-MnB,H12 has been determined, and the molecular structure is shown in Figure 4.5h Preliminary X-ray data have been reported for the Rb and Cs dodecahydro-closo-dodecaborates,M,2’ B,,H:;; the compounds are isomorphous Data for the double salts with MCl and belong to the space group Frn3n1.~~ have also been given. A

Figure 4 The structure of 5-THF-6-(CO),-6-MnB,H12 (terminal hydrogens omitted) (Reproduced by permission from Inorg. Chern., 1974, 13, 2261) 54

J . L. Little, S. S. Pao, and K . K. Sugathan, Inorg. Chem., 1973, 13, 1752. Z.B. Curtis, C. Young, R. Dickerson, K. K . Lai. and A. Kaczmarczyk, Inorg. Chem., 1974, 13, 1760. ’5‘7 J . W. Lott and D. F. Gaines, Inorg. Chem., 1974, 13, 2261. S I. Uspenskaya, K. A. Solntsev, and N . T Kuznetsov, J . Struct. Chem., 1973, 14, 140. 55

106 Inorganic Chemistry of the Main - group Elements Some new coupled products have been obtained from the lowtemperature decomposition of hydronium dodecahydrododecaborate(2 - ): H,O++2B1,H:;

H 3 0 ++ 2B,,H?;

and

+ H 2 0+ H, 3 Bz4H2,0H3+ 2H2 --j

B24H:;

Small amounts of B4,H:; were produced, as well as the expected products: B12HloOHz-and B,,Hl,(OH):-.'8 Carbaboranes.-The structure of 2,3,4,5-tetracarbahexaborane, C&H,, has been determined by an analysis of the microwave spectra of ten isotopic species. The short C-C bond lengths (1.43 A) suggest r-bonding character. The molecular dipole moment was found to be 2.21 *0.06 D.s9,"0 The closo-carbaborane 1,6-CzB4H6reacts with NMe, to give S-Me,N+nido-2,4-CzB4H,, which rearranges (thermally or in CHC1,) to give the 3Me,"-isomer. The parent 2,4-CzB4H; ion may be made either by the reaction of NaH with the 3-Me3N+or 5-Me," derivatives, or by the (slow) reaction of NaH or LiH with closo-1,6-CzB4Hs. The reactions are summarized in Figure 5 , the structures proposed being in accord with "B and 'H n.m.r. data." W

Figure 5 (Reproduced from J.C.S. Dalton, 1973, 2 115 ) Variable-temperature "B n.m.r. spectra of the C,Me,B,H; anion are consistent with a previously postulated structure involving removal of one bridging hydrogen from the C,R,B,H, nido -carbaborane structure, i.e. (8). Reactions of the anion with ICl (+ 2-C1C2Me2B,Hs, 3-C1C,Me,B,H5) and Br2(-+3-BrC2Me2B4H5) are believed to proceed via intermediates with 5X

59 "I

''

R. Bechtold and A . Kaczmarczyk. .1. Amer. Chem. Sac.. 1974. 96, 5953 .J. P. Pasinski and R. A. Beaudet, J.C.S. Chrrn. Cornrn.. 1973, (328. J . P. Pasinski and R. A. Beaudet. J . Chem. Phys., 1973, 61, 683. T. Onak, B. Lockman. and G. Haran. J.C.S. Dalton. 1973, 21 15.

Elements of Group III

107

H

(9)

(8)

bridged halogen atoms. The same paper6' also reported an analysis of the 220 MHz 'H n.m.r. spectrum of the parent carbaborane C2MeZB4H6. The species HC(BCl,), and H,C(BCl,), have been suggested as useful precursors in carbaborane Thus, the reaction:

(9) CH,(BCl,), + LiBH, occurred. The new compounds (CF3),PC(CH)B5H5and [(CF,),PC],B,H, are produced by the action of (CF,),PI or (CF,),PCl (in stoicheiometric amounts) on the dilithium derivative of C2B5H7.64 A new nido-carbaborane, CZB~HIO, may be prepared by the gas-phase reaction :

(Yield less than 5%). I.r., n.m.r., and mass spectral data indicate that the most likely structure is as shown in Figure 6, together with estimated bond lengths.65

Y

b

Figure 6 Nido-C,B,H,, (bond distances estimated from ADD theory) (Reproduced by permission from J. Amer. Chem. SOC., 1973, 95, 7514) Octaborane(l2) and,acetylene react in E t 2 0 solution to give a mixture of nido -dicarbanonaborane( 1l), B7C2HI1, and nido-dicarbadecaborane( 12), B,C,H,,. The "B n.m.r. data for the former indicate that this is the first

'' C. G . Savory 63 64

6s

and M. G. H. Wallbridge, J.C.S. Dalton, 1974, 880. D. S. Matteson and P. K. Mattschei, Inorg. Chem., 1973, 12, 2472. L. Maya and A. B. Burg, Inorg. Chem., 1974, 13, 1522. A. J. Gotcher, J. F. Ditter, and R. E. Williams, J. Amer. Chem. SOC., 1973, 95, 7514.

108 Inorganic Chemistry of the Main- group Elements carbaborane containing an integral BH, group, Figure 7. An analogous reaction of B,H,, with but-2-yne gives the mixture B,C2H,Me2+ B,C,H,,Me,. The former seems to possess a different structure from the parent carbaborane, containing 'extra' hydrogen atoms in bridging positions. The B,C2 species have the decaborane geometry, with carbon atoms at the 5 and 6 positions.66A minor product of the second reaction is a new 2,3-isomer of closo-BsC,H,Me,.

Figure 7 A possible structure for B,C,H,, (representing one enantiomorph of a d,l-pair) (Reproduced by permission from J. Arner. Chern. SOC., 1973, 95, 6254) The anion 7,8-C2B9HT2is oxidized by aqueous FeC13 to a weakly acidic nido-carbaborane, 5,6-C2BRH12. This in turn undergoes pyrolytic dehydrogenation at 240°C to give a high yield of a new closo-carbaborane, 1,2-C2B,H,,.67 An improved synthesis of nido -dicarbaoctaborane( 10) has been reported.68 This was carried out in a concentric cylindrical hot-cold reactor of capacity 750 ml. If a 1:2molar mixture of C,B,H, and B,H6 was kept in the reactor for 4 hours, a 35% yield of C,B,Hl, resulted. The reduction of 5,6-C2B8Hl2by Na-Hg in ethanol results in the formation of a new carbaborane, 6,9-C2B8Hl,(isostructural with B,,H:i)."' Reaction with D,O replaced H by D in the two bridging bonds and the axial C--H bonds, while the action of DCI-AICl, brought about deuteriation of the terminal hydrogen atoms at positions 1 and 3. The new closo-carbaboranes 1,2-B,C,H1, and 1,2-B,C2H8Me2are formed by pyrolysing nido-5,6-B,C2H,, and nido-5,6-B,C,H,,Me2, respectively."' The structure of the first species is believed to be that shown in Figure 8, from chemical and spectroscopic evidence. 66

67 68

69 'O

R. R. Rietz and R . Schaeffer, J. Arner. Chem. Soc., 1973. 95, 6254. J . PleSek and S. Heimanek. Coll. Czech. Chem. Comm.. 1974, 39, 821. T. J . Reilly and A. B. Burg, Inorg. Chem., 1974, 13, 1250. B. Stibr, J. PleSek, and S. Heimanek, Coll. Czech. Chem. Comm., 1974, 39, 1805. R. R. Rietz, R. Schaeffer, and E. Walter, J . Organometallic Chem.. 1973, 63, I .

Elements of Group 111 109 10-Acetyl, benzoyl, and formyl derivatives of 1-phenyl-p-carbaborane(8) have been obtained by reactions such as: p-C6H5CB&CLi

+ PhCOCl -+

p-C,H,CB,H,CCOPh

and their further reactions i n ~ e s t i g a t e d . ~ ~ Hetero-organic derivatives of 1-phenyl- 1,lO-dicarba-closo-decaborane( 10) containing bonds between the carbon atoms qnd Main-group elements such

Figure 8 Proposed structure for 1,2-B8C,H,, (Reproduced by permission from J. Organometallic Chem., 1973, 63, 1) as Si, Sn, Pb, P, and As can be synthesized by way of the lithium derivatives of the b ~ r a n e . ~Mercury ’ and methylmercyry analogues also exist, and a number of reactions have been described. 1,8-(MeC),B,H, is oxidized by sodium periodate in 2M-HCl and benzene while in acetic acid and at 25 “C to give 3-(H0)-1,8-Me2-1,8-B9C2Hs, benzene it yields 3,7-(HO),- 1,8-B9C,H7as the only B-hydroxycarbaborane. The monohydroxy-compound dimerizes on heating with loss of two equivalents of H, giving two ‘B9Cz’polyhedra. These are linked by oxygen bridges at the B(3,3‘) and B(7,7’) positions. In the presence of phenol this pyrolyses to form phenoxy-substituted carbaboranes (MeC),B,H,-,(OPh), when n = 6, 7, or 8. A number of other reactions of 3-(HO)-1,8-Me2-l,8-B9C’H8 were also r e p ~ r t e d . ’ ~ Two examples of heteroatom-containing electron-rich boranes have been reported. Thus: Na2(l,2-B9C,H,,) + PhAsC1, -+B,C,H,,AsPh which is related to BI,C2H:;, the BH being replaced by AsPh”. Similarly, the reaction of CsB,H,, with AsC1, and NMe, in MeCN gives BsH,As2S, 7’ 72

73

L. I. Zakharkin, V . N. Kalinin, and E. G. Rys, J. Gen. Chem. (U.S.S.R.), 1974, 44, 148. L. 1. Zakharkin, V. N. Kalinin, and E. G. Rys, J. Gen. Chem. (U.S.S.R.),1973, 43, 848. G. D. Mercer and F. R. Scholer, Inorg. Chem.. 1974, 13, 2256.

110

Inorganic Chemistry of the Main-group Elements

with a nido-structure related to B,C,H:;. Structures were deduced from mass-spectral and "B n.m.r. data.74 The benzodicarbollide ion (10) and its ( 1,4-dihydrobenzo)-derivative

have been prepared, and they may be reduced to the (2-)-ions, which in turn form rr-complexes with a number of transition metals. Figure 9 shows the structure proposed for the benzodicarbollyl-manganese(1) derivative:" "'Sn Mossbauer data have been reported for 3-Sn-1,2-B9C,H,,: S= 4.67 k 0 . 0 4 mm s-I, AE, = 3.83 +0.004 mm sC1. The isomer shift is consistent with a formal Sn" oxidation state, while the large quadrupole splitting arises from the marked asymmetry of the molecular s t r u c t ~ r e . ~ '

Figure 9 Structure diagram of the dibenzodicarbollylmanganese(I) tricarbony1 ion. The large open circle represents Mn; small open circles represent 0, darkened circles C, half-filled circles CH, and unmarked line junctions BH (Reproduced by permission from Inorg. Chem., 1974, 13, 671) 74

'' 7h

A. R. Siedle and L. J. Todd. J.C.S. Chem. Comm., 1973, 914. D. S. Matteson and R . E. Grunziger jun., Inorg. Chem., 1974, 13, 671. R. W. Rudolph and V. Chowdhry, Inorg. Chem., 1974, 13, 248.

Elements of Group I11 111 The reaction of (3)-1,2- and -1,7-B9C;11:; with Zr" or Hf" acetylacetonates produces (3)-1,2- or - 1,7-B9C,H;, salts of the hydroxyl-bridged cat~( ions [M4(a ~ a c )OH), A novel synthesis of closo - 1,7-BloC2H,2has been achieved by joining two one-carbon carbaborane units together, i.e. by heating 2-B5CH, to 250 "C. Figure 10 shows that this occurs when the two units come together with the bridging hydrogens close to each ~ t h e r . ' ~

O

H

Figure 10 Schematic representation of the fusion of two B5C skeletons to form the 1,7-B& skeleton (Reproduced by permission from lnorg Chern., 1974, 13, 755) The crystal structure of Me," PhCHB,,H,,CPh- has been determined; the ion has C, symmetry (disregarding the Ph ring orientations) and an opened icosahedral structure. One C atom is in the B l o c icosahedral fragment, with the other bridging two borons in the open face of this fragment.79 Thermal rearrangement of 9,12-dichloro-CC'-dimethyl-o -carbaborane at 420 "C gives mainly 5,12-dichloro-CC'-dimethyl-rn-carbaborane,whose molecular structure was determined by X-ray diffraction. This isomer is the only one (of 16 possible isomers) which can be produced from the cuboctahedral intermediate mechanism.80 A detailed X-ray study of the NMe: salt of CC'-dimethylundecahydrodicarba-nido -dodecaborate, Me2B,oC2H;1,has enabled all of the atoms, including hydrogens, to be located accurately (see Figure ll).81The anion possesses C, symmetry, with ten boron and one carbon atoms defining an icosahedral fragment with an open B,C face. The second carbon bridges two boron atoms in this face and is also bound to an exo-CH, and an endo-hydrogen atom. 7'

A. R. Siedle, J . lnorg. Nuclear Chem., 1973, 35, 3429.

'O

H.V. Hart and W. N . Lipscomb, Inorg. Ckem., 1973, 12, 2644.

'' R. R. Rietz and M. F. Hawthorne, Inorg. Chem., 1974, 13, 755. '' E. I. Tolpin and W. N. Lipscomb, Inorg. Chem, 1973, 12, 2257.

''

M. R. Churchill and 9. G . DeBoer, lnorg. Chern., 1973, 12, 2674.

Inorganic Chemistry of the Main-group Elements

112

Figure 11 A general view of the Me2BIoC,H;, anion (Reproduced by permission from Inorg. Chem., 1973, 12, 2674) Variable-temperature 'H n.m.r. studies on 1,2- and 1,7-bis(NN12) reveal dimethylcarbamoy1)-l,2- and 1,7-dicarba-closo-dodecaborane( that rotational isomers are present, and they enable estimates to be made of the enthalpies and entropies of. activation for NMe2 rotation.82 Fluoroalkenyl-o-carbaboranes, e.g. MeCB,,H,,C-CF=CFCl, can be reduced by NaBH4 or LiAlH, to mixtures of the hydrofluoroalken91 derivatives, but the stereospecificity of the reaction varies with the alkenyl group.83Similar reactions occur with m -carbaboranes. The carbaborane nucleus in 1-methyl-2-bromoethyl-o-carbaboraneis broken down on reaction with pyridine, forming two types of (3)-1,2-dicarba-undecaborane derivative. These contain both C-N and B-N bonds. Similar reactions occur with the 9-bromo- and 9,12-dibromo-deri~atives:~~

(R = H, Pr', or Ph; n = 1 or 2). The effectiveness of the catalysts is in the sequence: AlC1, AlBr, > BF,,Et,O > SnCI, >> FeCI,. The reaction occurs for

-

'' c'. H. Bushweller, C . Y. Wang, W. J. Dewkett, W. G. Anderson, S. A . Daniels. and 11. Beall, 83 84

J. Amer. Chem. SOC., 1974, 96, 1589. L. I. Zakharkin and V. N. Lebedev, J . Fluorine Chem., 1973, 3, 237. L. I. Zakharkin and V. S. Kozlova, J. Gen. Chem. ( U . S . S . R . ) ,1973, 43, 1091.

Elements of Group 111

113

0-,m-,

and p-carbaboranes, and always gives a mixture of the n = 1 and n = 2 species.85 The first secondary amine in the carbaborane series, 3,3’-iminodi-ocarbaborane, has been prepared by the following reaction with a catalytic amount of toluene-p-sulphonic acid?

Dilithio-o -carbaborane and aa ’-dibromo-o -xylene react to give dihydronaphthocarbaborane, which forms dibromodihydronaphthocarbaborane on allylic bromination. The reaction of the latter with NaI produces naphthocarbaborane (11).The reactivity of this species shows that there is

little, if any, effective 7r-bonding between the B,,, cage and the carbon ring system.87 Because of their possible aromatic properties, polycyclic derivatives containing the o -carbaborane ring are of particular interest. The carbaborane analogue of phenanthrene has now been synthesized.88Investigation of its properties shows that it is not at all similar to phenanthrene itself. Mass spectra have been reported for the B -[2-(trimethylsilyl)ethyl]-, the BB’-bis[2-(trimethylsilyl)ethyl]-, and the BB’-bis[2-(trichlorosilyl)ethyl]derivatives of o-, m-, and p - c a r b a b o r a n e ~ . ~ ~ Recent experiments show that carbaboranes are stable at 500-600 “C for an hour, but at higher temperatures pyrolysis occurs to give H2, CH,, and an insoluble polymeric residue of approximate composition C,.,H, ’B1,. In the presence of water, decomposition occurs at a lower temperature.” Introduction of phenyl groups on the C atoms of the carbaborane nucleus lowers the thermal stability. V. F. Mironov, V. I. Crigos, S. Ya. Pechurina, A. F. Zhigach, a n d V. N. Siryatskaya, Doklady Chem., 1973, 210, 42 1 . ’‘ L. 1. Zakharkin, V. N. Kalinin, and V. V. Gedymin, J. Gen. Chem. ( U . S . S . R ) ,1974, 44, 678. ’’ D. S. Matteson and R. A. Davies, Inorg. Chem., 1974, 13, 859. xu L. I. Zakharkin, A. V. Kazantsev, a n d B. T. Ermaganbetov, 1. Gen. Chem. (U.S.S.R.), 1974, 44, 220. ’’ V. N. Bochkarev, A. N. Polivanov, V. I . Grigos, and S . Ya. Pechurina, J. Gen. Chem. (U.S.S.R.), 1973, 43, 2393. 90 L. I. Zakharkin, V. N. Kalinin, T. N. Balykova, P. N. Gribkova. a n d V. V. Korshak, J. Gen. Chem. (U.S.S.R.), 1973, 43, 2249. x5

114 Inorganic Chemistry of the Main-group Elements "B n.m.r. spectra of all the isomeric carbaborane(l2) species, their B chloro-derivatives, and the dianions of both the unsubstituted and B chloro-carbaboranes have been measured to obtain further data on the structures of the dianions and the mechanism of their isomerization. The spectra of the dianions differ markedly from those of the mono-anions and the neutral species, indicating substantial redistribution of charge and bonding. Oxidation of the dianions was shown to be the determining step in the formation of o -carbaborane from rn -carbaborane, and of m carbaborane from p-carbaborane." A number of B -derivatives of m -carbaborane have recently been synthesized, an example being the formation of 2-vinyl- m -carbaborane according to the equation: CH,=CHBCl,

+C , B , H : ; - j

rn-HCBloH9(2-CH,=CH)CH

On oxidation with CrO,, the 2-carboxy-derivative is readily obtained, which can be converted with diazomethane into the methoxycarbonyl analogue. The carboxy-compound gives an acid chloride with PCl, and a benzoyl derivative on Friedel-Crafts reaction with benzene.92 A study of quadrupole-induced 'H-'O."B spin decoupling in carbaboranes (e.g. 1,7-dicarba-closo -dodecaborane) has shown that increasing molecular volume very probably leads to lH-lo,llB spin-spin coupling coalescence at increasing temperature^.^^ This is due to increasingly efficient 'O."B nuclear spin relaxation. "B-I'B n.m.r. double-resonance techniques, together with off -resonance proton-decoupling, have enabled all of the chemical shifts ("B) to be assigned in 8-iodo- 1,2-dicarbadodecaborane(12).94 "B n.m.r. data, including heteronuclear double-resonance, "Bd'H}, have been reported for ortho-, meta-, and para-isomers of the 12-carbaboranes and their B -monohalogeno-derivatives.9s Calculated frequences and integrated intensities, with theoretical i.r. spectra, for 0- and rn -dicarba-closo -dodecaboranes and their C-deuteriated derivatives have been reported.96This enabled an interpretation of all the intense bands observed in the spectra to be given. m-Carbaboranes with one or two silyl or disilanoxyl substituents have been investigated by i.r. methods, and the data compared with those for the corresponding silicon compounds without the carbaborane s ~ b s t i t u e n t . ~ ~ "

"

V. 1. Stanko. V. A. Brattsev, Yu. A. Gol'tyapin, V. V. Khrapoc. T. A . Habushkina, and -F. P. Klimova, J . Gen. Chem. (U.S.S.R.). 1974, 44, 319. L. I. Zakharkin, V. N. Kalinin, and V. V. Gcdymin. J. Gen. Chem. (U.S.S.R.), 1977. 43, 1956.

97 y4

" 96

y7

H. Beall, A. T. Elvin. and C . H. Bushwcller, Inorg. Chem., 1974. 13, 2031. B. E. Aufderheide a n d R. F. Sprecher, Inorg. Chern., 1974, 13, 2286. T. A . Babushkina. V. V. Khrapov, S. P. Gubuda, and L. D. Filizova. J . Struct. Chem., 1973, 14, 959. T. P. Klimova, I.. A . Gribov, a n d V. I. Stanko, Optics and Spectroscopy, 1974, 36, 650. N. V. Kozlova, L. P. Dorofeenko. A. I,. Klebanskii, and V. F. Gridina, J. Gen. Chern. (U.S.S.R.), 1974, 44, S54.

Elements of Group III

115

The rates of alkaline cleavage of 0-,m-, and p-carbaboranyltrimethylstannanes in MeOH vary in the sequence: ortho >> meta >parag8 A number of mono- or di-tropenylium-carbaboranes (dicarbahemiousenium and dicarba-ousenium ions), together with some related ‘ousenes’, have been reported (see Figure 12).99There is no evidence for T-interaction between the ring and the cage.

A

Figure 12 Ousene -type compounds: (A)[7,12’]-172-dicarba- hemi-ouseniurn ion (€3) [7,11”]-nido-(3)-172-dicarba-herni-ousene,(C)[7,7, 10ZsX]ousene,and (D)[7,7,121”]-1,7-dicarba-ouseniurn ion. The positions of the ring in (B), and of the second ring in (C) are not known, and are drawn as shown for convenience (Reproduced by permission from Inorg. Chem., 1974, 13, 862) Mass spectrometry can be used to distinguish reliably between the CC’-bishydroxymethyl derivatives of o - and rn -carbaboranes and their diacetates .loo The mutual arrangement of the methyl groups and halogen atoms affects the ‘H n.m.r. spectra of C-methyl- and CC‘-dimethyl-o- and -mcarbaboranes and their B -halogeno-derivatives. lo’ Comparison of data from pyridine and CC1, solutions confirms that the CH groups in 0- and mcarbaboranes can form hydrogen bonds. In aqueous alcohol solutions boric acid forms dinuclear complexes (BKioHi,O, 1)2-.102 YX 95,

I00

lo’

“)’

V . I . Stanko, T. V. Klimova, and I. P. Beletskaya, J. Organometallic Chem., 1973,61, 191. K. M. Harmon, A. B. Harmon, B. C. Thompson, C . L. Spix, T. T. Coburn, D. P. Ryan, and T. Y. Susskind, lnorg. Chem., 1974, 13, 862. A. F. Zhigach, V. T. Laptev, V. N. Bochkarev, A . B . Petrunin, B. P. Parfenov, and A. N. Polivanov, J. Gen. Chem. (U.S.S.R.),1973, 43, 866. L. I . Zakharkin, V. N. Kalinin, V. S. Kozlova, and V. A . Antonovich, J. Gen. Chem. (U.S.S.R.),1973, 43, 844. A. Ya. Putnin’, E. M. Shvarts, and A . F. Ievin’sh, Russ. J. Inorg. Chem., 1973, 18, 792.

116 Inorganic Chemistry of the Main-group Elements Metallo-carbaboranes.-A study of thermal rearrangements of nonicosahedral cobalta-carbaboranes of the general form (q-C5H5)CoC,B,H,+,, where n = 6, 7 , 8, or 10, leads to the following empirical rules concerning the migration of heteroatoms during thermal isomerizations: ( a ) the Co atoms will occupy the vertex of highest polyhedral coordination number and remain there. ( b ) the C atoms will not decrease their mutual separation (c) C atoms will migrate to vertices of lowest polyhedral co-ordination number. Once there, they will migrate only to an alternative low-coordination vertex. (d) C atoms will tend to migrate away from Co, subject to ( b ) and (c).lo3 Evans and Hawthorne have published a paper illustrating further applications of the general polyhedral expansion reactions of metallocarbab0~anes.l'~The preparations of species Cp2C02C,B,H,+2 are here described. One of the proposed structures is shown in Figure 13, based on i.r., n.m.r., and mass spectra.

Figure 13 The proposed structure of (C5H5),Co2C2B,H9 (Reproduced by permission from Inorg. Chem., 1974, 13, 869) 103

to4

D. F. Dustin, W. J . Evans, C. J. Jones, R. J. Wierwma, H. Garg, S. Chan, and M. F. Hawthorne, J. Amer. Chem. SOC., 1974, 96, 3085. W. J. Evans and M. F. Hawthorne, Inorg. Chem., 1974, 13, 869.

Elements of Group I11 117 The isotropic shifts of the "B and 13Cnuclear resonances in paramagnetic metalloboranes, CpM(C2BnHn+,),M(C,B,H,+,), (M = Cr"', Fe"', Ni"', or ~ ~ mode of electron Co", n = 6 , 7, 8, or 9), have been e ~ a 1 u a t e d . lThe delocalization is primarily L to M charge-transfer, except for icosahedral Co", where it is from M to L. The extent of delocalization is small, and largely restricted to the metal bonding face. The magnitudes and directions of the isotropic shifts of the metallocarbaboranes and metallocenes are very similar, implying that the energetics of the M-L interaction are similar. A number of new Fe" and Fe"' metallocarbaboranes have been synthesized, both in solution and in the vapour phase, from nido-C2B4H8and closo-C,B,H,. Thus, treatment of 2,4-C,B,H7 with sodium naphthalide, FeCl,, Na'Cp-, and 0, gives (a-2,4-C,B,H6)-(.rr-2,4-c2B4Hs)Fe"'(Cp). Treatment of this with Na-Hg followed by HC1 produces the FeI' species, e.g. (.rr-2,4-C2B4H6)Fe"(Cp).'06 A gas-phase reaction of 2,3-C2B,H, with Fe(CO), gives (.rr-2,3-C,B4H6)Fe(CO), (12) and (n-2,3-C2B,H,)Fe(CO),,

Fe

oc'~o'co

which is to be the subject of an X-ray study to be reported later. 2,4C,B,H, reacts with Fe(CO), at 280 "C, giving the 2,4-isomer of the former and (r-C,B,H,)Fe(CO),. The crystal structure of the dicarbacyclopentaboranyliron tricarbonyl complex, (C2B3H,)Fe(C0)3,mentioned in the previous Report, is shown in Figure 14.'07This reveals that the carbaboranyl ring is planar. Several metallocarbaboranes of Fe, Co, and Ni have been prepared by the direct reaction of 1,5-CtB3Hs, 1,6-C2B4H6,or 2,4-C2B,H, with organometallic reagents in the gas phase or in solution.'08 No prior cageopening step was necessary. As examples of such reactions, Fe(CO)s or (qC,H,)Co(CO), with C,B,H, gave the six-vertex products (OC),FeC,B3H5 or (q -C5H5)CoC2B3Hs,together with the seven-vertex complexes (OC),Fe,B,H, and (.rr-C,H,)Co,C,B,H,. Similar reactions occurred with C,B4H6 to give primarily seven-vertex species (MC,B,) and with C,B,H, to give

-

'05

106 lo'

R . J. Wiersema and M. F. Hawthorne, J . Amer. Chem. SOC., 1974, 96, 761. L. G . Sneddon, D. C. Beer, and R. N . Grimes, J. Amer. Chem. Soc., 1973, 95, 6623. J.-P. Brennan, R. N. Grimes, R . Schaeffer, and L. G . Sneddon, h o r g . Chem., 1973,12,2266. V. R . Miller, L. Ci. Sneddon, D. C. Beer, and R . N . Grimes, J. Amer. Chem. SOC.,1974, 96, 3090.

118

Inorganic Chemistry of the Main - group Elements

Figure 1 4 Molecular structure of B3C2H,Fe(CO), (Reproduced by permission from Inorg. Chern., 1973,12,2266) eight-vertex complexes (MC,B,). Structures were proposed for the compounds prepared, on the basis of the usual physical methods. A further substantial number of new Co and Ni metallocarbaboranes have been reported by Grimes et al. Thus the reaction of Na'C,B,H; with CoC1, and NaC,H,, followed by exposure to air, water, and acetone, gives (r-2,3-C,B,H6)Co( r -C,H,), (r-2,3-C2B,H7)Co(r-C,H,), and (r-2,3C,B,H5)Co,( r-C5H5),. These complexes may also be obtained by reduction of 2,3-C2B4H8with sodium naphthalide, followed by reaction with CoCl,, Na+C,H;, air, and water-see the reaction scheme in Figure 15. If the reaction sequence is carried out starting from 1,6-C2B,H6, the chief pro(.~~-C,B,H,)CO,(.~~-C~H~)~, and [a-5-(1ducts are (.~~-C,B,H,)CO,(~~-C~H~)~, C,,H,)(r-2,4-C,B4H,)]Co(~-C,H,) (see Figure 16).lo9 The structure of Cs+[(C,H,)Co(CB,H,)]- has been determined by X-ray diffraction. The Co"' atom is sandwiched between the C,H; and CB,Hi moieties, with Cs' ions in general positions. The CoCB, skeleton is almost a tricapped trigonal prism, with 2 borons and one carbon atom in the low-co-ordinate 'cap' positions. The Co is bonded to five boron atoms (average bond distance 2.01 A).'"

"")

'I('

R. N. Grimes, D. C. Beer, L. G. Sneddon. V. R. Miller, and R. Weiss, Inorg. C1hrm., 1974, 13, 1138. K. P. Callahan. C . E. Strouse, A. L. Sims, and M . F. Hawthorne, Inorg. Chem., 1974, 13, 1393.

Elements of Group III

119 1NOH ‘H2

-

No+

Figure 15 Reaction scheme for the synthesis of cobalt rnetallocarbaboranes from 2,3-C2B4H,. Open circles are BH groups, solid circles CH groups (Reproduced by permission from Inorg. Chern., 1974, 13, 1138)

Figure 16 Reaction scheme for the synthesis of cobalt rnetallocarbaboranes from 1,6-C2B4H6 (Reproduced by permission from Inorg. Chern., 1974, 13, 1138)

Inorganic Chemistry of the Main -group Elements 120 Crystals of Ph,PMe' [(B,C,H,)Mn(CO),]- are triclinic, space group Pi."' The manganese is bonded to two carbons (at 2.04 A) and three borons (two at 2.35 A, one at 2.23 A) of the eight-atom carbaborane cage. The structure of 2,6-di-q -cyclopentadienyl-octahydro-1,10-dicarba-2,6has been dicobalta-closo-decaborane, 2,6-(r)-C5H,)-2,6-Co,-1,10-C2B,Hs, deduced from X-ray diffraction. The polyhedral framework is a distorted, bicapped square antiprism, with carbons at the caps and one cobalt in each tropical plane. The cobalt atoms are bonded to each other [2.489(1)A apart], this being the first confirmed metal-metal bond in a bimetallocarbaborane.", A number of thermally induced cobalt-migration reactions in cobaltacarbaboranes have been observed for the first time,113e.g. heating 2,6,1,10(C,H,),Co,C,B,H, to 280 "C produces 2,7, 1,10-(CsH5)2C02C2B6H,. This involves the migration of a cobalt atom from a vertex adjacent to cobalt to a vertex separated from cobalt by one boron atom. When Na'Cp- and FeCl, are added to CpCo"'(C2B,H,), previously reduced by sodium naphthalide, a new heterobimetallocarbaborane (13),

(13) CpCo"'(C,B,H,)Fe"'Cp, is produced. 'Another Co"'/Fe"' carbaborane was produced by the reaction of CpCo"' (C,B,,H,,) with ethanolic KOH in the I l l 'I2 'I'

F. J. Hollander, D. H. Templeton. and A. Zalkin, Inorg. Chrm., 1Y73. 12, 2262. E. L. Hod. C. E. Strouse, and M. F. Hawthorne, Inorg. Chem., 1973, 13, 1388. W. J . Evans, C. J . Jones, B. Stibr, and M . F. Hawthorne, J. Organometallic Chem.. 1973, 60, C27.

Elements of Group

m

121

A

Figure 17 Decomposition of the suggested 1 ,2,8,3,6-(CsH,)3C03C2B7H9 to 1,8,2,3-(CsH,),CoC,B,H, (Reproduced from J.C.S. Chem. Cornm., 1973, 706) presence of FeC1, and C,&, and so two quite different types of reaction may be used to synthesize such bimetallocarbaboranes."" 2, 1,6-C,HsCoC2B7H9, when reduced with Na-naphthalene in THF and subsequently treated with Na'Cp- and CoCl,, gives the expected (C5H,)2Co,C2B,H9, and a new trimetallic carbaborane formulated as (C,H,)Co,C,B,H,. The latter decomposed in solution to give the former, and the reaction is believed to be as shown.in Figure 17. Thus the structures (on the and basis of n.m.r. and mass spectral data) are 1,2,8,3,6-(C,H5),Co3C,B7H9 1,~,~,~-(C,H,)COC,B,H,.'~~ When tetrakis(triethy1phosphine)nickel is added to a solution of the arachno-carbaborane l,3-B7C,H,,Me,, one molecule of H, is evolved and red crystals of Ni(B,C,H,Me,)(PEt3), (14) are deposited. A number of other n

8 Mc5

'I4

D. F. Dustin, W. J. Evans, and M. F. Hawthorne, J.C.S. Chem. Comm., 1973, 805. Evans and M. F. Hawthorne, J.C.S. Chem. Comm., 1973, 706.

"' W. J.

122 Inorganic Chemistry of the Main - group Elements Ni and Pt complexes also reacted to give products containing this ligand.Ii6 The structure of (14) was confirmed by X-ray diffraction, i.e. the geometry is that of a nido-carbaborane, but, unlike the previously reported Co(C2B7Hll)(CsH5),this compound may be regarded as a 1,2,3-q-bonded compound of Ni". These new complexes are therefore analogous to h3-allyl species, the first time that such a structure has been reported. Some new cobalt complexes of the nido- 11-atom metallocarbaborane class have been reported by Hawthorne et al.,"' e.g. X-[9-(q-CsHs)-11C,H,N-7,8, 9-C2CoB8Hlo] and X-[ 1,2- C,B,H, ,-3 ,1'-Co-7'-C,H,N-2',4'C2B8H,](15). The structure of only one enantiomer of (15) is illustrated. 10

n

A new experimentally convenient route to icosahedral bimetallocarbaboranes has been reported by Evans and Hawthorne."' Thermally induced intermolecular metal- transfer reactions of the type:

I" I17 I IX

M. Green, J . Howard, D. L. Spencer, and F. G . A . Stone, J.C.S. Chem. Cornrn.. 1974. 1S3. C. J . Jones, J . N . Francis, and M. F. Hawthorne. J. Amer. Chem. SOC.. 1073, 95, 7633. W . J . Evans and M. F. Hawthorne, .I. Amer. Chem. SOC.. 1974, 96, 301.

Elements of Group I11 123 occur, yielding 5 isomeric species, which could be separated chromatographically. One was unambiguously characterized as 2,9-(q-C,H,)-2,9-Co21,12-C2BsHlo (16).

0BH CH

The crystal structure of 2,3-(q -CsH5)2-2,3-Co21,7-C2B,H,, has been determined.119The molecule may be described as a distorted icosahedron in which the two Co atoms occupy adjacent vertices [2.387(2) A apart], being co-ordinated also to two cyclopentadienyl rings [average Co-C bond distance 2.05(2) A]. Polyhedral expansion of 1,6-C2B8HI0 gives Et,N+[(C,H,)CoC,B8H,oCoC2B8Hlo]-.An X-ray study showed the structure to be (17), with the geometrical parameters listed in Table 2.”” This represents the first crystallographic confirmation of ClV octadecahedral geometry. Na,B,,HloCH(THF)2 reacts with GeCl, to give, on subsequent treatment with Me1 or EtI, 1,2-Bl,HlOCHGeR (R= Me or Et).”’ If the Me derivative Icy 120

”’

K . P. Callahan, C. E. Strouse, A. L. Sims, and M. F. Hawthorne, Inorg. Chern., 1974, 13, 1397. G. Evrard, J . A. Ricci jun., I. Bernal, W. J . Evans, D. F. Dustin, and M. F. Hawthorne, J.C.S. Chem. Comm., 1974, 234. G. S. Wikholrn and L. J. Todd, J . Orgartometallic Chem., 1974, 71, 219.

124

Inorganic Chemistry of the Main -group Elements (' >.B 115)

is refluxed with benzene and piperidine, further addition of NMeiClprecipitates Me,NIBloHloCHGe]. The latter reacts with Cr(CO), to give Me," 1,2-B loHloCHGeCr(CO),].

Table 2 Average interatomic distances/A in Et4N'[(C,H5)CoC2B8H10CoC2B~HJ Co(l)-Co(2) Co(1)-C (terminal cage) Co( 1)-C (bridging cage) Co(1)-B (bridging cage) Co(2)-C (bridging cage) Co(2)--B (bridging cage) Co(2)-C (of C5H, ring) C-B (bridging cage) C-B (terminal cage) B-B (bridging cage) €3-B (terminal cage)

3.173 1.978 2.094 2.090 2.0 I 0 2.048 2.063 1.702 1.595 1.797 1.812

Removal of bridging protons from B,,CH, (by ethanolic KOH), with subsequent addition of C,H, and CoC1, and oxidation, gives [(q -C5H5)Co'II (?r-7-B,oCH,,)]-.'22 The neutral Nil" analogue (q-C,H,)Ni'"(q -7BloCHll)was also reported, and this undergoes thermal rearrangement to a -2- and -l-BloCHll). mixture of the isomers (q-C5H5)Ni'"(r) If the 13-vertex cobaltacarbaboranes (q-C,H,)COC~B,~H,~ are treated with ethanolic KOH and cyclopentadiene in the presence of an appropriate metal salt, new 13-vertex bimetallocarbaboranes are produced. These may contain similar or dissimilar metal atoms, and they contain one less boron atom than the original monometallocarbaborane. This replacement of a 12'

R. R. Rietz, D. F. Dustin, and M . F. Hawthorne, inorg. Chew., 1974, 13, 1580.

Elements of Group 111 125 boron atom by a metal atom has been termed a 'polyhedral subrogation' reaction. An example of such a reaction is: 2[4-(q - C ~ H ~ ) - ~ -1,8-C2B,oH12] CO+ 3CoC1, + 2C&

1

+ 6Et0-

KOH EtOH

2[4,5-(q-C,H,)z-4,5-C0,1,8-C,B,HIl] + 2B(OEt)3+ 2H2 + COO+ 6C1A similar reaction involving FeC1, produced ( 18).123

The RhI-carbaborane complex (Ph3P)2Rh(CBloHloCPh)forms orthorhombic crystals. The Rh-carbaborane interaction comprises a Rh-C a-bond and a Rh-H-B bridge (19).12' An alternative description is of

electron donation from a suitable Rh hybrid orbital into an empty orbital delocalized over the C-B-H group of the anionic (CBloHloCPh)-ligand. Treatment of (Me,SOH)' [(C,B,H,,),Co]- with S,Cl2 in CH2Cl2,followed by alkaline methanolysis, forms the anion 8,8'-S(C2B,HIo),Co-(isolated as 124

D. F. Dustin and M. F. Hawthorne, J. Amer. Chem. SOC., 1974, 96, 3462. G . Allegra, M. Calligaris, R. Furlanetto, G. Nardin, and L. Randaccio, Cryst. Struct. Comm., 1974, 3, 69.

126 Inorganic Chemistry of the Main-group Elements the Cs’ Addition of dimethyl sulphate gave the neutral complex 8,8’-MeS(C2B,H,,),Co. Two Rh hydridometallocarbaboranes have been prepared which are active catalysts for the homogeneous hydrogenation of hexenes.lZ6They are 3,3-(Ph3P),-3-H-3, 1,2-RhC2B,H,, and 2,2-(Ph3P),-2-H-2, 1,7-RhC2B,H,, . They are prepared by the reaction of Me3NH+salts of (7,8-C2B,H,,)- or (7,9-C2B,HJ with the [Rh(PPh3),]+ cation in methanol solution. These complexes also catalyse the H-D exchange reaction of D, with carbaboranes very effi~ient1y.l~’Thus, deuteriation of C,B,,H,, occurs at least one order of magnitude faster with them than with any other catalyst so far examined. An X-ray investigation of the structure of closo- 1,l-(Me2PhP),-2,4-Me21,2,4-PtC2B,H, has been carried out.lZ8The structure found is (20), with the

”’ J. 12’

’*’

PleSek, S. Hefmanek, and Z . JanouSek, Chem. and Ind., 1Y74, 108. T. E. Paxson and M. F. Hawthorne, J. Amer. Chem. SOC.,1974, 96, 4674. E. L. Hoe1 and M. F. Hawthorne, J. Amer. Chem. SOC., 1974, 96, 4674. M Green, J . L. Spencer, F. G. A . Stone, and A. J. Welch, J.C.S. Chem. Comrn., 1974, 571.

Elements of Group III

127

Pt atom situated approx. 1.75 A above the CZB3 bonding face. The species nido- 10,10-(Et3P),-2,8-Me,- 10,2,8-PtC2B,H, is prepared from closo-Me,1,6-C,B7H, and Pt(PEt,),. The Pt co-ordinates boron atoms 5, 6, 7, and 9, producing a nido- 10-atom polyhedron approximating to a bicapped square antiprism. N.m.r. data on the latter indicate that it is stereochemically non-rigid. The fluxional ‘red’ isomer of (n-C,H,)Co(B,,C,H,,) crystallizes in the The Cp ligand is symmetrically orthorhombic space group P ~ a (C:,).”’ 2 ~ bound to the Co, while the B10C2Coskeleton defines a triangulated (1,5,6,1) 13-apex docosahedron, the equatorial C-B-C-B-B-B belt being bonded to cobalt. Some peculiarities in this structure are illustrated in Figures 18 and 19. Thus the hexagonal bonding face of the carbaborane ligand is non-planar, and within this ligand there are some unusual bonding arrangements. This is most marked within the four-membered units B(2)B(3)-B(8)-C(7) and B(2)-B(6)-B(12)-C(7); the B(12)-C(7) and B(8)-C(7) bonds are very short [1.527(6), 1.429(10)A] and C(7) is only five-co-ordinate. B(2), however, is linked to 7 other atoms, the bonds B(2)-B(8) and B(2)-B(12) being very long. Polyhedral expansion reactions have been extended to produce the first 14-vertex metallocarbaboranes.130 Thus, X-[4,1,1 2-CsH,CoCzB10H12]gives

Figure 18 A view of the (T~-C,H,)CO(~,~-B,,C~H,,) molecule showing the two anomalous four-membered systems : B(2)-B(3)-B(8)-C(7) and B (2)-B(6)-B( 12)-C( 7) (Reproduced by permission from Inorg. Chem., 1974,13, 1411) 129

13”

M. R. Churchill and B. G. DeBoer, Inorg. Chem., 1974, 13, 1411. W. J . Evans and M. F. Hawthorne, J.C.S. Chem. Comm., 1974, 38.

128

Inorganic Chemistry of the Main -group Elements BI

88

&,c o

CP5

CP3 CP4

Figure 19 A view of the (T-C,H,)CO(~,~-B,~C~H,,) molecule, showing nonplanarity in the hexagonal bonding face of the carbaborane ligand. (Reproduced by permission from Inorg. Chem., 1974,13, 141 1) X - [1,14,2,10-(CSH5)2Co,C,B,oH,,](see Figure 20). A similar reaction, starting with the 4,1,8-isomer, yields an isomeric product, (1,14,2,9).

Figure 20 The formation and proposed structure of (C,H,),Co2C,B,,H,, (Reproduced from J.C.S. Chem. Comm., 1974, 38) Cobalt(I1) complexes of dpc (21) include Co(dpc)(NCS),, [Co(dpc),Br]', and [Co(dpc),I]', which have been prepared and ~haracterized.'~' They are

(21)

'"

W. E. Hill. W. Levason, and C . A. McAuliffe, Inorg. Chem., 1Y74, 13, 244.

Elements of Group III

129

reasonably stable in the absence of hydroxylic solvents. The only Ni" complex prepared was [Ni(dpc),I]', which gave an electronic spectrum consistent with trigonal-bipyramidal co-ordination at the nickel atom. The reaction of 2-R-1,2- and 7-R-1,7-B,,C,Hll (as the 1-Li derivatives), where R = Me or Ph, with (Ph,P)RhCl gives rise to an unusual series of three-co-ordinate complexes containing a metal-carbon a-bond: (Ph,P)Rh(~-carb).'~~ These readily react with 0, to give an oxygen complex [with 40,) at 900cm-'] and (reversibly) with CO to form (PPh,) Rh(CO),( u - carb) . The reaction of 1-lithiocarbaborane derivatives with cis-(PR:),PtCl, or trans -(PR:),PtCl, yields cis-(PR:)PtCl(a-carb) and cis(PR:),Pt(PR:CH,CHR')(u-carb), respectively (R'= Et, Pr", or Ph; R2= H or Me)."' Compounds containing B-C Bonds.-An a b initio MO calculation has been carried out on H3B,C0.13, The adduct H3B,C0,NMe3is only stable at low temperatures, decomposing to CO and H,B,NMe3 on ~ a r m i n g . ' ~1.r. ' assignments and some "B n.m.r. data have been reported for the adduct, the assignment of v(C0) to a band at 1798 cm-' being consistent with the postulated O + N co-ordination. B,H,CO may be prepared in a convenient one-step synthesis from B2H6 and CO in a hot-cold r e a ~ t 0 r . lThe ~ ~ carbonyl derivative may then react with C2H4 to give (CH,),B,H,. The structure of this is (22), as shown by 'H

\ H-B-H

/

n.m.r. spectroscopy. The i.r. spectra of this and its C-methyl and CC'dimethyl derivatives are also consistent with this structure. Thermal decomposition of triborane(7) carbonyl, B,H,CO, gives the new species bis(carbonyl)diborane(4), B,H,(CO),. This is relatively stable, and preliminary X-ray data suggest that it possesses a 1,2-disubstituted, ethanelike with B-B 1.78(1), B-C 1.52(1), C-0 1.125(7), B-H(1). 1.14(6), and B-H(2) 1.11(6)A. 13*

133 134

136

13'

S. Bresadola and B. Longato, lnorg. Chem., 1974, 13, 539. S. Bresadola, A. Frigo, B. Longato, and G. Rigatti, Inorg. Chem., 1973, 12, 2788. S. Kato, H. Fujimoto, S. Yamabe, and K. Fukui, J. Arner. Chem. SOC., 1974, 96, 2024. J. C . Carter, A. L. Moye, and G. W. Luther, J. Arner. Chem. SOC., 1974, 96, 3071. T. Onak, K. Gross, J. Tse, and J. Howard, J.C.S. Dalton, 1973, 2633. J . Rathke and R. Schaeffer, Inorg. Chem., 1974, 13, 760.

130

Inorganic Chemistry of the Main-group Elements ~-Bis(cyanotrihydroborato)-tetrakis(triphenylphosphine)dicopper(I)crystallizes in the space group P2Jn.13* The H,BCN- ligands bridge the' two copper atoms, forming a ten-membered non-planar ring, with Cue * -Cu= 5.637(2) A. The structure is a rare example of a hydroborate ligand bonded by only one of its H atoms to a metal atom, and the geometry of the BH,CN ligand is close to that of CH,CN in related complexes. Bis(cyanotrihydroborato)- 1,1,4,7,7-pentamethyldiethyIenetriaminecopper(I1) crystallizes in the space group Pbca. The Cu is five-co-ordinate, forming a distorted square-based pyramid, and'the two NCBH; ligands are distinct, one apical [r(Cu-N) = 2.153(3) A] and one in the 'square plane' [r(Cu-N) = 1.980(4) hi]."' Ab initio MO calculations on vinylborane, H,C=CHBH,, yield a value for the barrier to rotation about the B-C bond of 7.6 kcal ~ O I - ~ . The ~"" optimum values for the C=C and B-C bond lengths were 1.327 and 1S S 4 A (planar form) or 1.32 1 and 1.574 A (for the perpendicular conformation). The i.r. and Raman spectra of trivinylborane, B(CH=CH,),, may be assigned on the basis of the planar, C,,, structure determined by electron diffraction. The values of v(B-C) and v(C=C) are consistent with some B-C ~r-interaction.~"~ A second, independent, investigation of this vibrational spectrum agrees with these conclusions for the solid phase, but in the fluid phases an additional conformer, of C, symmetry, was detected. 14' This form may be obtained by twisting the vinyl groups out of the molecular olane. Microwave, i.r., and Raman spectra were also obtained for vinyldifluor~borane.'"~ The barrier to rotation about the two-fold barrier was calculated to be 4.17 kcal molF'; this is quite large, but it is not large enough for B-C multiple bonding to be postulated. Vapour-phase i.r. and Raman spectra of HC=CBX, ( X = F or Cl) have been obtained for several isotopic species.'"" Almost complete vibrational assignments were made for both molecules. Some assignments have also been proposed from the i.r. and Raman spectra of X,BCH=CHBX, and X,BCH,CH,BX, (X = F or Cl).l"' The allyl-borane (23) is much more stable than other allylborane systems, most of which undergo spontaneous rearrangements. 146

13'

'" 14') 141

'" '43 '44

14'

K. M. Melmed, T.-I. Li, J. J . Mayerle, and S. J. Lippard. J. Amer. C'hem. SOC..1974, 96,6Y. B. G. Segal and S. J. Lippard. Inorg. Chern., 1974, 13, 822. H. M. Seip and H. H. Jensen. Chem. Phys. Letters. 1974. 25, 209. A. K. Holliday, W. Reade, K . R. Seddon, and I. A. Steer, .1. Organometallic Cham., 1974, 67, I. J . D. Odom, L. W. Hall, S. Riethmiller, and J . R. Durig, Inorg. Chem., 1974, 13, 170. J . R. Durig, R. 0. Carter, and J . D. Odom, I n o r g . Chem., 1974. 13, 701. J . M. Burke, J . J . Ritter, and W. J . Lafferty, Spectrochirn. Acta, 1974, 30A, 993. W. Haubold and J. Weidlein. Z . anorg. Chem., 1974, 406, 171. K. G. Hancock and J. D. Kramer, J. Amer. Chern. SOC.,1973, 95, 6463.

Elements of Group 111

131

Et 'BNMe,

Fe I

(23)

(24)

/ MeCH \CH=CH,

BI, reacts with ferrocene at -10 "C in benzene to give (24).14'This reacts further to form the 1,l'-di-B1,-derivative. Heating 1,2-bis(dichlorylboro)ethane gives a low yield of the boraadamantane (BCl),(CH),.'"" The C1 atoms may be substituted by Br (using BBr3) or Me (using SnMe,). Mass and vibrational spectra have been presented for the chloro-species. A rhombohedra1 boron carbide B& results from the pyrolysis of BBr,Ch-H, mixtures on Ta or BN substrates at 900--1800°C. It has the crystal-chemical composition B,,(CBC), i.e. B,, icosahedra and linear CBC Excess carbon up to a resultant formula of B,,C, can be accommodated in the structure. A number of new tetragonal and orthorhombic B/C phases have been B,,B,(BC)] and ~haracterized.'~'The tetragonal species were B51C [i.e. under B25C (i.e. B,,B,C,), which result from pyrolysis of BBr,-C%-H, normal pressure. The decomposition of B13+CI, at 1050 "C and lo-' Torr produces B,,C, [i.e. B,,(BC)C,].A11 contain four B,, icosahedra and four single atoms (3B + lC, 2B + 2C, and 1B+ 3C, respectively). The icosahedra are linked by direct B-B bonds and by bridging with the single atoms. The B3&48), which latter reaction also gives the orthorhombic B8C (i.e. contains several B& units linked by numerous additional carbon atoms in the ab plane.

-

-

-

-

Aminoboranes and Other Compounds containing B-N Bonds.Structural parameters for the planar and orthogonal forms of H,BNH, have been computed from ab initio calculations.1s1The best estimate of the internal rotation barrier is 33.3 kcal mol-'. Using the geometry recently deduced for H2NBF, by microwave spectroscopy, MO calculations (CNDO and INDO) have been carried out on this The following conclusions were reached: (a) The 120" FBF and HNH angles are due to repulsive N- .F and B- .H interactions. ( b ) The

-

'47

14'

14Y 150

15'

-

W. Ruf, M. Fueller, and W. Siebert, J. OrganometaIlic Chem., 1974, 64, C45. M. S. Reason, A. G. Briggs, J. D. Lee, and A. G. Massey, J. Orgaltometallic Chem., 1974, 77,

C9. K. Ploog, J. Less-Common Metals, 1974, 35, 131. K. Ploog, J. Less-Common Metals, 1974, 35, 115. 0. Gropen and H. M. Seip, Chem. Phys. Letters, 1974, 25, 206. C. Leibovici, J.-F. Labarre, and F. Gallais, Compt. rend., 1974, 278, C , 327.

132 Inorganic Chemistry of the Main - group Elements B-N bond order is approx. 1.3. ( c ) There is very little transfer of charge F,B + NH2, only ca. 0.015 electron. Tetrachloroaminoborane, Cl,BNCl,, has been characterized as an intermediate in the reaction: 3BC1, + 3NC1, + (ClBNCl), + 6C1, The following vibrational assignments, in particular, were given for this species: B-N stretch (A,) 1350 ("B), 1312("B); B-C1 stretch (B,) 1026 ('OB), 986 ("B); B-Cl stretch (A,) 446; N-Cl stretch ( B , ) 735; and N-C1 stretch (A,) 541 cm-'. The tetrachloroaminoborane is extremely and unpredictably explosive, so great care must be exercised.lS3 An ab initio M O calculation carried out on H3B,NH3(borazane) gave an insight into the origin of charge transfer and bond formation between BH, and NH,.15" The calculation involved an expansion of the MO's of the addition compound in terms of those of the separate NH, and BH,. Ab initio LCAO-MO-SCF calculations on the same species have given values for the electric field gradients, electric fields, diamagnetic shieldings, dipole moment, second moment, and diamagnetic su~ceptibility.'~~ A C N D 0 / 2 calculation performed on Me,N,BH, indicates that the preferred conformation is staggered, and that the energy barrier to the process: staggered S eclipsed is 2.91 kcal mol-' (experimental value 3.4, theoretical value for Me,P,BH, is 4.09 kcal m ~ l - ' ) . l ~ ~ Stepwise formation of B -halogenated amine-boranes occurs by the reaction of halogens or H X with the parent amine-borane. The progress of the reaction may be followed by monitoring the 'H n.m.r. spectrum of the reaction The end product of the bromination reaction on Me3N,BH3 is Me3N,BBr,, while for Me,CNH,,BH, chlorination yields Me,CNH2,BCl, and fluorination [Me,CNH,]'BF;. A detailed assignment and normal-co-ordinate analysis has been reported for the vibrational spectra of Me,N,BH,, Me3N,BD3, (CD,),N,BH,, and (CD,),N,BD,.15* The B-N and C-N stretching modes are extensively mixed, although the bands at 680, 660, 641, and 610 cm-' (for the 4 isotopic species) possessed more than 65% of B-N stretching character. The B-N stretching force constant was calculated as 2.59 mdyn A-1. Evidence has been presented for the mechanism of the halogen-exchange processes in the systems Me,BX,+BY,, where X and Y are ha10gens.l~~ ls3

156 157

t TX

J . G . Haasnoot and W. L. Groencvcld, Z . Naturforsch., 1974, 29b, 52. H . Fujimoto, S . Kato, S . Yamabe, and K . Fukui, J . Chem. Phys.. 1974, 60,572.

M . Dixon and W. E. Palke, J. Chem. Phys., 1974, 61, 2250. F. Crasnier, J. Chim. phys., 1973, 70, 1731. .I. M. Vanpaaschen. M. CJ. Hu, L. A. Peacock, and R. A. Geanangcl, Synth. React. lnorg. Metal-org. Chew., 1974, 4, 11. J . D. O d o m . J. A. Barnes, B. A. Hudgens, and J . R. Durig, J . Phys. Chem., 1974, 78, 1503. B. W . Benton and J . M. Miller, Canad. J. Chem., 1974, 52, 2866.

Elements of Group III

133

Isotopic labelling shows that no B-N bond rupture occurs, and that X or Y could be the heavier halogen. Except for Me3N,B13a bridged intermediate (five-co-ordinate at B) may be postulated. In the Me,N,BI, case ionic predissociation (B-I bond breaking) is indicated. Gas-phase halogenexchange reactions always occur via B-N bond cleavage. The role of co-ordinated BH, and BH, groups as proton acceptors in hydrogen-bonding has been studied, using the complexes between phenol and Me,N,BH2X (X = H, C1, Br, or I), py,BH3, and Et3P,BH3.16'Enthalpies of formation were deduced from measurements of the absorbance of the free O H stretching band over a range of temperature. Values of - A H fell within the range 1.7-3.5 kcal mol-l, while in the Me3N,BH2X series the strengths of the hydrogen bonds fell in the order: H > Cl> Br> I. The monochloroborane complex with triethylamine (ClBH,,L) reacts at 120 "C with heptamethyldisilazane, eliminating Me,SiCl, but the expected product, H,BNMeBH,, is unstable, and only decomposition products (-BH-NMe-), can be isolated. With the corresponding ether complex at 60 "C, reaction gives the silyl system H,BNMeSiMe, when the molar ratio is 1:1, but with a larger amount of the chloroborane adduct the product is a diboranyl compound Me,SiNMeBzH,.'6' X-Ray diffraction studies on 2,6-lutidine-chloroborane, C,H,N,BH,Cl, give the following bond lengths and angles: B-Cl 1.901(3), B-N 1.590(4), B-H 1.07(3), 1.17(3) A, LNBCl 107.3(2)", LBNC 121.0:, 120.2(2)0.162 Near- and far-u.v. spectra have been recorded for the aminoboranes (Me,N),BX,-,, where n = 1, 2, or 3; X = H, Me, F, C1, or Br.16' For the mono-aminoboranes the 7~ -+ n* transitions dominate the spectra, but for the di- and tri-aminoboranes there are also Rydberg series and some single Rydberg transitions, partly preceding the 7~ + T * band. Transamination of (dimethy1amino)diphenylborane with 2-, 3-, or 4aminopyridine gives the corresponding (pyridinylamino)diphenylboranes, while the B -triphenyl-N-tris(4-pyridyl)borazineis obtained by transamination of bis(dimethy1amino)phenylborane with 4-amin~pyridine.'~" Resonance line broadening due to chemical exchange and quadrupoleinduced relaxation in the 'H and "B n.m.r. spectra of some boron-nitrogen adducts ArNMe,,BY, (Y= halogen) has been observed and used to determine the mechanism of amine scrambling in these adducts.16' This is thought to occur via a unimolecular ionization rather than a B-N bondrupture process.

'"

M. P. Brown and P. J. Walker, Spectrochim. Acta, 1974, 30A, 1125. A. F. Zhigach, E. S. Sobolev, R. A. Svitsyn, and V. S. Nikitin, J . Gen. Chem. (U.S.S.R.), 1973, 43, 1949. I 6 2 W. R. Clayton, A. V. Fratini, R. Remmel, and S. G . Shore, Cryst. Struct. Comm., 1974, 3, 151. 163 W. Fuss, Z . Naturforsch., 1974, 29b, 514. L64 W. L. Cook and K. Niedenzu, Synth. React. Inorg. Metal-org, Chem., 1974, 4, 53. 16' J. R. Blackborow, J.C.S. Dalton, 1973, 2139.

Inorganic Chemistry of the Main-group Elements 134 The crystal and molecular structures of ammonia-isothiocyanoborane, H,N,BH2NCS, have been determined;166these show that the B-N(of NH,) NCS) bond length is bond length is 1.578(8)A while the B-N(of 1.534(8) A. A study of the exchange reactions of adducts of NN-dimethyl-o -tohidine with BCl, and PhBCl,, o-MeC6H,NMe2,BC1,, and o-MeC6H,NMez,PhBC1,, and of NN-dimethylaniline with PhBCl, and PhNMez,PhBClz, has shown that, as for the adducts p-ClC6H,NMe2,BC1, and PhNMe2,BC1,, the ratedetermining step in amine exchange is usually a unimolecular ionization of the a d d ~ c tThe . ~ ~first ~ three adducts, however, show equilibrium ionization that is an order of magnitude greater than that of the last two. Cyanoborane adducts of morpholine and dimethylamine undergo the following hydrolysis reaction: R,NH,BH,CN

+ 2 H z 0+ 2 0 H - -+ R,NH + B(OH), + 2H,+ CN-

Kinetic studies suggest that the mechanism involves removal of the Nbonded proton by OH- in a rapid pre-equilibrium, followed by the ratedetermining, dissociative decomposition of the resultant conjugate base.168 The course of the reaction between halogenoboranes and the aminobenzonitriles depends upon the position of the NH, group.169With the 3- and 4-amino-derivatives the products are the corresponding amine-boranes and compounds obtained by loss of hydrogen halide, (25) and (26). With the 2amino-benzonitrile, however, the nitrile group is inserted into a B-halogen

bond (27), and derivatives of the 1,3,2-diazaboranaphthalene ring ( 2 8 ) result by elimination of HX.

Ihh lh7 IhX

lhY

S. S. Kendall and W. N . Lipscomb. Inorg. Chem., 1973, 12, 2920 J . R Blackborow, M. N. S. Hill, and S. Kumar, J.C.S. Dalton, 1974, 311. C. Weidig, S . S. Uppal, and H . C . Kelly, Inorg. Chern., 1974, 13, 1763. A Meller. W. Maringgele, and G. Marech, Monatsh.. 1974, 105, 637.

Elements of Group I11

135

The thermal decomposition of hydrazine-borane is a rather complex process, but the first stage appears to be a loss of molecular hydrogen. The major, final product may be formulated as (H2BNHNHBH2),.'70 14Nand "B chemical shifts have been reported for 19 silylaminoboranes, e.g. R:B-BR2-SiMe, (R' = Me, R2= H, Me, Et, P i , Bus, or But; R' = Et, R2= H or Me; R' = Ph, R2= H or Me), (29), and B[NMeSiMe,],."' (pp)-nSiMe,

I

MeB

I SiMe, (29)

Bonding between B and N, as well as geometric effects, were used in analysing the data. The Si-N bonds of B(NMeSiMe,), are successively cleaved by Me2BBr As n to give all the members of the series (Me2BMeN),B(NMeSiMe,)3-,.'72 increases these products become increasingly susceptible to thermal decomposition. 'H and "B n.m.r. spectra were obtained and discussed. Tris(organoamino)boranesmay be rapidly and conveniently prepared by the interaction of BF,,Et,O and N-lithio-dialkyl-, -diaryl-, and -alkylarylamines in THF: R'R'NH

+ n-C,H,Li

3R1R2NLi+ BF,,OEt,

hzfeR'R2NLi+ n-C4Hl, THF,:ebanc.> (R'R'N),B + 3Et,O + 3LiF

The procedure is more general and less sensitive to steric effects than previous ones, and it gives well-known, as well as new, tris(organoamino) boranes in high yields.", BCl, forms 1: 1 adducts with methacrylonitrile, CH2=C(Me)CN, and Nbenzylidenemethylamine, PhCH=NMe, but organoboranes, e.g. BEt, or B(C3H,),, add across the C = N bond to give CH,=C(Me)-C(R)=N-BR, and PhCHR-NMe-BR,, respe~tive1y.l~~ Variable-temperature "F n.m.r. spectra of mixtures of an amine (A) and B(OR)F, between -40 and +60"C reveal that at low temperatures ( < -30 "C) the adduct A + B(OR)F, is stable. Above this temperature rearrangement occurs, yielding B(OR), and A + BF,.175 17"

17'

17'

'73 174

175

A. F. Zhigach, V. V. Zakharov, G. B. Manelis, G. N. Nechiporenko, V. S. Nikitin, and B. M. Esel'son, Russ. J. Inorg. Chem., 1973, 18, 931. H. Noth, W. Tinhof, and B. Wrackmeyer, Chem. Ber., 1974, 107, 518. H. Noth and W. Storch, Chem. Ber., 1974, 107, 1028. W. R. Purdum and E. M. Kaiser, J. Inorg. Nuclear Chem., 1974, 36, 1465. A. Meller and W. Gerger, Monatsh., 1974, 105, 684. J. P. Tuchagues and J. P. Laurent, J. Inorg. Nuclear Chem., 1974, 36, 1469.

136 Inorganic Chemistry of the Main - group Elements Contrary to reports in the literature, the reaction of (dialky1amino)diboranes with tertiary amines proceeds via an intermediate complex in which the diboranyl group is preserved. The final products are mixtures of aminoboranes and amine-boranes. 176 Reactions with sym - and asym dimethylhydrazines are also reported, giving products such as H,B-NMeNMe-BH2 and Me,NNH-BH,, respectively. A number of photochemical reactions of tetrakis(dimethylamin0)diborane, B2(NMe2)+have been i n ~ e s t i g a t e d . The ' ~ ~ products of the reaction in CCl, solution at 2 5 4 0 ° C using 300nm radiation are (Me,N),BB(NMe2Cl), B(NMe2),, and (Me,N),CH,. Cationic boron(m) chelates, formulated as (30), can be prepared by transamination reactions between B(NEt,), and biguanides, followed by treatment with HCl.'78Similar guanylurea derivatives can also be obtained.

t

c1-

Compounds with the molecular formula (C,H,N,),BX, where X = F or C1, have been previously isolated from reactions of halogenoboranes and phthalodinitrile. The structure of the chlorine compound has now been determined and shows a phthalocyanine-like structure (3 l)."' The system is bowl-shaped, in contrast to the planar phthalocyanine structure. The boron atom is co-ordinated to three N atoms (at 1.467 A, i.e. short) and one C1 (1.863 A). The .rr-electrons in the 14-membered ring form a quasi-aromatic conjugated .rr-system. Compounds containing B-P Bonds.-CND0/2 calculations on Me3P,BH, lead to a minimum energy in the staggered conformation, with rotational barriers about the P-B and P-C bonds of 4.09, 3.83 kcal mol-', respectively.180 A similar calculation for H,B-P(NH,), suggests that there is little .rr-bonding in the P-B bond.lS1 17h

177

17'

''' I80

181

A . F. Zhigach, R. A . Svitsyn, and E. S. Sobolev, .I. Gen. Chrm. ( U . S . S . R . ) , 1973, 43, 1031. K. G. Hancock, A . K . Uriarte, and D . A. Dickinson, J . Amer. Chem. SOC.. 1973,95,6980. A . Maitra and D. Sen, Indian J . Chem., 1974, 12, 183. H. Kietaibl, Monutsh., 1973. 105, 40s. M.-C. Bach-Chevaldonnet, F. Crasnier, J.-F. Labarre, and C . Leibovici, J . Mol. Structure, 1974, 20, 131. R. Dorschner. F. Choplin, and G. Kaufmann, J . Mol. Structure, 1974. 22, 321.

Elements of Group 111

137

Detailed studies have been made on the vibrational spectra of F,P-BH, was calculated for the and F3P-BD3.'" A force constant of 2.46 mdyn k1 P-B bond stretching, while assignments of 224 cm-' and 167 cm-' were made for the torsional modes of the H and D compounds, respectively. These are consistent with barriers to rotation of 4.15(H), 4.31(D) kcal mol-'. 1.r. and Raman spectra of H,P,BX, and D,P,BX, (X = C1, Br, or I) have been reported and assigned. A normal-co-ordinate analysis, (modified Urey-Bradley force field) confirmed the assignments. All the adducts gave a best frequency fit for an assumed value for the HPH bond angle of ca. 105-1 06". The systems PC1,-BF,, PC1,-BCl,, MePC1,-BF,, MePC1,-BCl,, Me,PClNo evidence was BF,, Me,PCl-BCl,, and Me,P-BCl, have been found for PC1,-BF, or -BCl, adducts, nor for MePC1,-BF,, although MePCl,-BCl, is formed. Other previously reported species were confirmed. The basicities for the P-compounds appear to be in the sequence Me,P> MezPCl>MePCl, ( >> PCl,). The reaction of PMe,C1+B,H6 yields the new adduct ClMe2P-BH,.'85 A complete vibrational assignment has been proposed for this, and some 'H and "B n.m.r. data have also been reported. 1.r. and n.m.r. parameters (especially '.IpB)have been reported for the newly characterized series of adducts R3-,XnP -+ BH,, where R = But, 0 < n < 3 , and X = F or C1.'86 A further, extensive, investigation of the n.m.r. spectra of phosphineborane adducts has been made by Rapp and Drake."' The following data were obtained: (a) 'H and "B n.m.r. parameters for R,PH3-,,BX, (R = Me or Ph; n = 0, 1, or 2; X = H, F, C1, Br, or I): (b) 'H, "B, and ,'P parameters for the BX,H3-, (n = 0, 1, or 2; X = C1, Br, or I) adducts of all R,PH,-,; and ( c ) I9F parameters for all of the compounds R,PH3-,,BF3 except PH3,BF3. BCl,, BBr,, and BI, form 1: 1 adducts with MePCl,. BF, does not react, and B2H6 gives a mixture of products.188Halogen exchange is found to occur in all the MePC1, adducts with BBr, and BI,. Adducts of BI, and BBr, with various tertiary phosphines and their chalcogenide derivatives, together with 'H and "B n.m.r. spectra of many of these, have been reported.189 Although the 'H(CH,)-3'P coupling constants are nearly identical in the series Me3P,BX, (X = F, C1, Br, or I), J,, for the 182

'*' 185

J. D. Odom,S. Riethmiller, S. J. Meischen, and J. R. Durig,J. Mol. Structure, 1974,20,471. J. E. Drake, J . L. Hencher, and B. Rapp, J.C.S. Dalton, 1974, 595. R. T. Markham, E. A. Dietz jun., and D. R. Martin, J. Inorg. Nuclear Chem., 1974, 36, 503. J . D. Odom, S. Riethmiller, and J . R. Dung, J. Inorg. Nuclear Chem., 1974, 36, 1713. C. Jouany, G. Jugie, J.-P. Laurent, R. Schmutzler, and D . Stelzer, J. Chim. phys., 1974, 71, 395. B. Rapp and J. E. Drake, Inorg. Chem., 1973, 12, 2868. R . M. Kren, M. A. Mathur, and H. H. Sisler, Inorg. Chem., 1974, 13, 174. M. L. Denniston and D. R. Martin, J. Inorg. Nuclear Chem., 1974, 36, 1461.

138

Inorganic Chemistry of'the Main-group Elements Me,P,BI, species is much lower than the values for other members of the series. The nature of donor-acceptor interactions in aminophosphine-borane adducts may be elucidated by studying the chemical behaviour of the BH, The P atom is a better acceptor group and 'H, IIB, and 31Pn.m.r. than N towards B when the P and N are directly linked (as in Me,NPMe,), although the N co-ordinates preferentially to B when the P and N are separated by a methylene bridge [e.g. in (Et,NCH,),P]. Treatment of H2P(BH3),Na with an ethereal solution of HCl at -96°C leads to the formation of an associated p -phosphinodiborane, (F-H,PB,H,),. 1.r. and n.m.r. ("B) spectroscopy point to the formation of B-HB bridges. Thermal decomposition leads to elimination of B,H, and formation of polymeric phosphinoborane, and this is analogous to the behaviour of p-HzN-BzH5.191 Similar compounds in which the P atom is substituted by an organic group can be prepared by reactions of MePH(BH,),Li, Me2P(B H,) ,Li, or PhPH(BH,) ,Li. N.m.r. and i.r. data have been listed for the adduct PF2(CH=CH2),BH,.'92 v(PB) is at 584 cm-'. Compounds containing B-0 Bonds.-Mehrotra et al. have written a review on compounds containing M-0-B linkages, i.e. metalloboroxane~.'~~ Boron reacts with oxygen at atmospheric pressure and temperatures of 1250--1400°C (in the presence of traces of Pt) to give the suboxide B,O, which was characterized by X-ray powder d i f f r a ~ t i 0 n . l ~ ~ A study has been made of the temperature dependence of the isothermal compressibility of B,0,.195 Corsaro and Jarzynski have reported on the thermodynamic properties of B,O, in the glass ~ e g i 0 n . l ~ ~ No binary solid phases are observed in the B,03-MOO, 1.r. spectra of BO; in potassium and rubidium halide lattices have been observed, and the data so obtained used to determine the anharmonic force-field of BO;.198 Assignments of some vibrational modes of BO:- in an indium borate crystal have been attempted, together with some for lattice modes.199 A theoretical analysis has been made of the miscibility gaps in the alkali-metal borates, based on the concept of regular solutions. In each system the structural units which control the entropy of mixing are thought 1 YO

c'. Jouany, J.-P. Laurent. and G. Jugie, J.C.S. Dalton, 1974, 1SlU. H. Hofstiitter a n d E. Meyer, Monatsh., 1974, 105, 712. I y 2 E. L. Lines and L. F. Centofanti, Inorg. Chem., 1974, 13, 1517. S . K . Mehrotra, G . Srivastava, and R. C. Mehrotra, J. Organometallic Chem., 1974, 73, 277. Iq4 H . Jean-Blain a n d J. Cueilleron, Compt. rend., 1973, 277, C, 977. 195 J. A. Bucaro and H. D. Dardy, J. Chem. Phys., !974, 60, 2559. I Yh R . D. Corsaro and J. Jarzynski, J. Chem. Phys., 1974, 60, 5128. Iy7 V. T. Mal'tsev, P. M. Chobanyan, and V. L. Volkov, Russ. .I. Inorg. Chern., 1973, 18, 1068. I Y x D. F. Smith jun., Spectrochirn. Acta, 1974, 30A, 87s. l Y y R. Frech, J . Chem. Phys., 1974, 60, 1678. IY'

Elements of Group I11

139 to be the stoicheiometric compounds at the limit of the alkali-rich edge of the gap, and a complex boron trioxide structure.’00 The depression of the transition temperature of Glauber’s salt has been measured in borate solutions to gain information on the nature and concentration of the species present.’’* The data support the previous observation that in the boron concentration range 0.1-0.2 mol 1-’ only monomers and tetramers are present. Bismuth orthoborate, BiBO,, is obtained by melting a mixture of H,BO, and Bi,O, in stoicheiometric proportions, and Two polymorphs (distinguished by their i.r. and Raman spectra) are produced depending upon the cooling conditions. At 600°C BiB03 rapidly decomposes to a mixture of 2Bi203,B203and 3Biz03,5B203. The isomeric 12-tungstoborates have been shown to be respectively quadratic and hexagona1.*03Conditions for their isolation in pure form, without recourse to tedious fractional recrystallization, were established. Heats of reaction of pentasubstituted Li+,Na+,and K’ tungstoborates with NaOH have been determined.’04 The salts do not contain hydrogen ions which could react with OH- as readily as the ions in tungstoboric acid. Tungstoboric ($B203,12W0,,nH2), tungstovanadoboric (iB203,10W03,V,O,,nH,O), and molybdotungstoboric ($B,0,,6MoO3,6WO,,nH2O) acids give rise to two titration jumps in potentiometric titrations. These correspond to 3 and 5 dissociable protons (in amphoteric solvents such as methyl ethyl ketone).’” In a protic solvent (acetic acid) the acids are only tribasic, since here the boric acid is the complex-forming species. A study of the H3B0,-CaC1,--H,O-i-C,Hl,OH system reveals that the extraction of boric acid depends chiefly upon [CaC12].’06 Complexes of borate with certain sugars give rise to broadened 13Cn.m.r. spectra, due to the presence of more than one conformer, and to the presence of two types of complex:

I -C-O,’k

‘OH

,o-c-

I

-c-0’

Replacement of borate by the diphenylborinate ion gives sharp signals, since no 13C-11B coupling seems to occur.207

201

’”’ ’(’’ 204

*”’ ’06

’07

P. B. Macedo and J. H. Simmons, J. Res. Nat. Bur. Stand. Sect. A, 1974, 78, 53. M . V. S. Jain and C. M. Jain, Indian J. Chem., 1973, 11, 1281. M. J. Pottier, Bull. Soc. chim. belges, 1974, 83, 235. G. Hem6 and A . TCze, Compt. rend., 1974, 278, C, 1417. V. I. Spitsyn, M. M. Sadykova, and G . V. Kosmodem’yanskii, Russ. J. Inorg. Chem., 1973, 18, 998. I. K. Latichevskii and N. A . Polotebnova, Russ. J. Inorg. Chem., 1973, 18, 1756. E. E. Vinogradov and L. A . Azariva, Russ. J. Inorg. Chem., 1973, 18, 859. P. A . J. Gorin and M. Mazurek, Canad. J. Chem., 1973, 51, 3277.

140 Inorganic Chemistry of the Main-group Elements Phenylboronic acid forms a 1:l complex with lactic acid in which the ligand hydroxyl proton is replaced by B.'" The stability constant of the species is (3.7 kO.4) x lo-,. The fully protonated lactic acid reacts with a rate constant of 140 1 mol-1 s-l (f10"/0), while the acid anion gives a rate constant of 1500 1 mol-' s-l (*look). Tris(trialky1tin)borates B(OSnR,), (R = Me, Et, Pr, Bun, Bu', or Ph) are produced by the reaction of boric acid with R,SnOH or (R,Sn),0.209They react with B,O, to form the trialkyltin metaborates (R,SnOBO),. The NN-diethylhydroxylamine derivatives of B and A1 are readily obtained from reactions in which the hydroxylamine is refluxed with an alkoxy-derivative of the Group I11 element:210 M(OR),+ nEt,NOH + M(OR),-,(ONEt,),

+ nROH

(M = B, R = Pr' or Bun, n = 2 or 3; M = Al, R = Pr', n = 1-3). C N D 0 / 2 calculations on the adduct Me2S0,BF, suggest that a rocking motion of the OBF, group about the S-0 bond occurs, together with a rolling of the BF, about the 0-B bond.'ll The conformational equilibrium of this complex was therefore said to be associated with a 'rock and roll' internal motion. 'H, "B, 19F, and 31P n.m.r. spectra of the systems R:MO,BF,-R:M'O (where M,M' = N, P, or As; R',R' = various alkyls) show that the donors are displaced from the complexes in the sequence R,NO b R,AsO > R,PO. These differences in the donor power of the oxygen atom can only be related to changes in the M-0 bond which are associated with the nature of M.," Methyl acetate and its sulphur analogues, MeC(=X)Y Me (where X, Y = 0 or S), all form adducts with BX, via the C=O or C=S group.213 Enthalpies of formation have been measured for BF, adducts of a number of carbonyl compounds PhCOX. The electron-donating strength of the oxygen atom is directly related to the inductive effect of the group X, although the establishment of a basicity scale for the carbonyl function must also take into account steric effects.214The following order was found for the basicities: benzaldehyde = acetophenone > hindered ketones > benzoic esters == a -chloroacetophenone > benzyl chloride. 1.r. and mass spectral data show that an intermediate in the production of 25dimethyl- 1,3,4-trioxadiborolan by the reaction of Me,BH,BH, + 0, is Me,B OOH (dimet hylboryl hydroperoxide).'l Two members of a new class of boron peroxides, (PrnO),BOOB(OPrn), 209 '''I

'11 ?I2

'I3 214 215

S . Friedman. R. Pace, and R. Pizer, J . Amer. Chern. Soc., 1974, 96, 5381. S. K. Mehrotra, G. Srivastava. a n d R . C. Mehrotra, J . Orgunornetallic Chem., 1974, 65, 361. C . K . Sharma. V. D. Gupta, and R. C. Mehrotra, Indian J. Chem., 1974, 12, 218. G. Robinet, J.-F. Labarre, and C. Leibovici, Chem. Phys. Letters, 1973, 22, 356. K. Bravo, M. Durand, J.-P. Laurent. and F. Gallais. Cornpt. rend.. 1974. 278, C, 1481). M. J . Bula, J.,S. Hartman, and C . V. Raman, J.C.S. Dalton, 1974, 725. J.-F. Gal, L. Elegant, arid M. Azzaro, Bull. Soc. chim. France, 1974. 41 1. L. Barton a n d J . M. Crump. Inorg. Chem.. 1973, 12, 2506.

Elements of Group 111 141 and the n-butyl analogue, have been obtained by treating the dialkoxychloroborane with hydrogen peroxide in diethyl ether.216A mechanism for the thermal decomposition to boric acid and B(OR), is postulated in which the first stage is homolytic cleavage of the 0-0 bond. A rapid method for determining quantitatively the water content of a large variety of hydrated salts depends upon measuring the volume of ethane liberated when the compound is treated with triethylboron in the presence of small amounts of pivalic acid. One ethyl group is removed per hydrogen according to the equation:217 2Et,B + H,O + 2EtH + (Et,B),O Boric acid forms a stable 2: 1 complex with triquinoyl, which can be isolated as the dipotassium salt (32).218 This supports the formulation of triquinoyl as the dodecahydroxycyclohexane.

2K'

The crystal structure of nickel orthoborate has been deterrnined.,l9 All of the B atoms are triangularly co-ordinated. Heating the mixture T12C03+ Nb,OS+ B 2 0 3to about 1000 "C produces the new multiple oxide TlNbB20,.ZZoThis forms orthorhombic crystals (space group PN21a). Octahedra around Nb are joined at the comers, giving a zig-zag chain in the a-direction. These chains are linked by 2 BO, triangles sharing one 0 atom. The octahedra and triangles form rings around the T1 atom, giving 6 oxygens as nearest neighbours. The following mean bond lengths were found: Nb-0 1.98, T1-0 3.00, B(1)-0 1.35, and B(2)-0 1.36A.

'"V. P. Maslennikov, G. I. Makin, V. N . Alyasov, (U.S.S.R.), 1973, 43, 1954. "' R. Koster and W. Fenzl, Annalen, 1974, 69. 218 219

220

and Yu. A . Aleksandrov, J. Gen. Chem.

T. Goto and M. Nagao, Bull. Chem. SOC. Japan, 1974, 47, 246. J. Pardo, M. Martinez-Ripoli, and S. Garcia-Blanco, Acta Cryst., 1974, B30, 37. M. Gasperin, Acta Cryst., 1974, B30, 1181.

142

Inorganic Chemistry of the Main -group Elements

1.r. and Raman spectra of glasses with the composition Na,O,xB,O, (x = 2 , 3 , 4, 5, 6, or 9) reveal that, as the Na,O concentration rises, an

increasing proportion of the B atoms are four-co-ordinate. A band at ca. 800cm-’ is assigned to rings of the form (33).”l

Kurnakovite, Mg[B,O,(OH),](H,O),,H,O, forms triclinic crystals, of space group P i . The structure contains discrete [B,O,(OH),]’- groups, which share OH groups with Mg(OH),(H,O), tetrahedra to form chains.*” The fifth H,O molecule lies between these chains. Crystallographic parameters have been obtained for TlB,O, (orthorhombic, space group P212121)and TlB,O, (also orthorhombic, the space group is probably Pbca, by analogy with the related K’ Sodium diborate, Na,0,2B203, is triclinic (space group P i ) . The polymeric borate anion forms layers composed of di-pentaborate groups and triborate groups with one non-bridging oxygen, which is a novel feature for d i b ~ r a t e s . ~The ’ ~ B-0 bond lengths were as expected. La,Sr,(BO,), forms orthorhombic crystals (space group Pc2,n; a = 8.78, b = 16.84, c = 7.42 A). The lattice is built up of isolated BO, triangular units (average B-0 distance 1.37 A).z25 Lithium aluminoborate, Li6[A12(B03),],is isostructural with the analogous galloborate, forming triclinic crystals (space group The anionic framework [Al,(BOJ-], contains chains parallel to the (010)-plane, built up of rings formed by 2 A1 tetrahedra and 2 B triangles, interlinked in one direction by two other B triangles. An X-ray study on Pr,Sr,(BO,), (space group P2,Cn) shows the presence of triangular BOi- ions linked to the cations to give a three-dimensional There are two different types of Pr environment; each is co-ordinated to 8 oxygens in a distorted ‘biclinoid’ arrangement. Pr-0 distances are respectively 2.22-2.82 A and 2.47-3.05 A. Three different Sr2+co-ordination polyhedra are found, with co-ordination numbers of 10, 8, and 9, respectively, Orthorhombic MnB,07 belongs to the space group Pcba. The B407 unit A . Bertoluzza, B. Righetti. and S . Schiavina. Atti Acud. n u z . Lincei. Rend. C l a w Sci. jk. mat. nut., 1972, 53, 421. ’” E. Corazza, Acta Cryst., 1974,B30, 2194. 2 2 3 M . Touboul. Cornpt. rend., 1973, 277, C, 102s. 2 2 4 J . Krogh-Moe, Acta Cryst., 1974, B30, 578. z z 5 G. K. Abdullaev, Kh. S. Mamedov. and S. T. Amirov, Soviet Phys. Cryst., 1974, 18, 675. ”‘ G. K. Abdullaev and Kh. S. Mamedov, Soviet Phys. Cryst., 1974, 19, 98. 2 2 7 K. K . Palkina, V. G. Kuznetsov, and 1.. G . Moruga, J . Struct. Chem., 1973. 14, 988.

143 Elements of Group I11 consists of two BO, tetrahedra with one common oxygen atom, each sharing two other 0 atoms with 2 triangular BO, groups; the average distance B-O(tet) distance is 1.473 A, the average B-O(triang.) 1.368 A.228 Direct reaction of M3P208and Na,B,O, (M = Ca or Sr) gives apatite-like Na, (P04)6Bx+zy 02,which contain linear [0-B-01units, phosphates, M9+y with B-0 bond lengths of 1.25 k0.02 A number of i.r. bands have been assigned for the polyborates K[B,O,(OH),] and K,[B60,(OH),] by using partial de~teriation.~,’ The potassium cobalt hexaborate {K,,CO}[B,O,(OH),],,4H20 forms t i clinic crystals of space group C:-PT. The structure contains isolated [B607(OH)6]2a-Sodium triborate, a-Na20,3B20,, is monoclinic (space group P2Jc). The borate anion forms two separate, interpenetrating, infinite frameworks. Each of these consists of pentaborate and diborate groups (in equal amounts).232 Caesium triborate, on the other hand, crystallizes in the orthorhombic space group P212,21. The borate anion forms a threedimensional framework built up from triborate groups.233 Phase relationships have been examined in the system B,O,-K,O-WO,; a congruently melting, ternary compound 3Kz0,3B203,4W03 is formed.234The phase diagram of the PbO-B,03-W0, system has also been reported.235 Potassium borate glasses of the composition Kz0,4Bz03can be crystallized to give a compound Kz0,3.8B203 (i.e. 5K,0,19B20,). The crystal structure of this has been determined; it belongs to the space group C2/c (monoclinic). The polymeric borate anion is three-dimensional, and built from interconnected pentaborate groups, triborate groups, BO, tetrahedra, and BO, Hexalead pentaborate, 6Pb0,5B20,, is triclinic. The structure contains isolated B,,O::- polyanions, which are built up from two diborate groups linked by two BO,

Compounds containing B-S or B-Se Bonds.-A high-temperature reaction (1100 “C) between H2S and crystalline boron produces a transient thioborine molecule, HBS.238A photoelectron spectrum of this was obtained, showing adiabatic ionization potentials of 11.11*0.03, 13.54k0.03, **’

S. C. Abrahams, J. L. Bernstein, P. Gibart, M. Robbins, and R. C. Sherwood, J. Chem. Phys., 1974,60, 1899. ’” C. Calvo and R. Faggiani, J.C.S. Chem. Comm., 1974, 714. 230 G. Heller and A. Giebelhausen, J. Inorg. Nuclear Chem., 1973, 35, 3511. 2 3 ’ E. Ya. Silin’, Ya. K. Ozol, and A. F. Ievin’sh, Soviet Phys. Cryst., 1973, 18, 317. 2 3 2 J. Krogh-Moe, Acta Cryst., 1974, B30, 747. 233 J . Krogh-Moe, Acta Cryst., 1974, B30, 1178, 234 A. G. Bergman, V. L. Volkov, and V. T. Mal’tsev, Russ. J. Inorg. Chem., 1973, 18, 573. 235 V. T. Mal’tsev, A. G. Bergman, P. M. Chobanyan, and V. L. Volkov, Russ. J . Inorg. Chem., 1973, 18, 1764. *’‘ J. Krogh-Moe, Acta Cryst., 1974, B30, 1827. 237 J . Krogh-Moe and P. S. Wold-Hansen, Acta Cryst., 1973, B29, 2242. 238 H. W. Kroto, R. J. Suffolk, and N. P. C. Wcstwood, Chem. Phys. Letters, 1973, 22, 495.

144

Inorganic Chemistry of the Main -group Elements and 15.83 f O . l eV. The absence of vibrational fine structure due to bending motion is interpreted as indicating that all three states of HBS associated with these bands are linear. Another report of the photoelectron spectrum of this species is consistent with the above.239 Microwave spectra at zero field of the J = O-, J = 1 transitions in H' 'B3'S, D1'B3'S, and D"B"S yield nuclear quadrupole constants of -3.72k0.03 ("B) and -7.91 k0.03 ("B) MHz.*" Measurements in a high electric field gave a value of Ipl= 1.298f0.005 D for the electric dipole moments. A near-Hartree-Fock wavefunction for thioborine, HBS, has been used to calculate various molecular properties at the experimental geometry."' These agreed rather well with available spectroscopic data. 1.r. and Raman spectra have been recorded and interpreted for B(SH),, B(SD),, BX(SH)', and BX(SD),, where X = B r or I.*'* All are consistent with the molecules being planar. A CNDO/2 calculation on the BCl,(SH) molecule yields a barrier to internal rotation of 2.18 kcal mol-' (compared to an experimental value of ca. 1 kcal m ~ l - ' ) . ' ~ ~ Gas-phase electron-diff raction measurements on methylthiodimethylborane, Me,BSMe, suggest that the skeleton is probably planar, although values of up to about 25" for the torsional angle about the B-S bond could not be ruled The most important molecular parameters are : B-S 1.779(5), C-S 1.825(4), C-B 1.570(4) A, LBSC 107.2(10)", LSBC(Me) 124.0(8)", and 115.3(6)". The molecular skeleton of B(SMe), was found by electron diffraction to be essentially planar, with r(B-S) = 1.805(2), r(S-C) = 1.825(3) A, and LBSC = 104.5(3)0.245 Pyridine and methyl(methylthio)boranes, BMe,(SMe),-,, form adducts which are more stable than the corresponding NMe, adducts. The acidity of these boranes decreases with an increased number of SMe groups.z46 Photoelectron spectra have been reported for a series of methylthio- and methoxy-boranes Me,-,BX, (X = SMe or OMe).247These were compared and assigned using modified CND0/2 calculations. Substituent effects and chemical shifts (6"B) were consistent with significant 7-contributions to the B-S bond. The complexes BX1,R3PY(X = C1, Br, or I but not F; R = Me, Ph, or Cy; 23y 240

241

242 243 244 245 246

247

T. P. Fehlner and D. W. Turner, J. Amer. Chern. Soc., 1973. 95, 7175. E. F. Pearson, C. L. Norris, and W. H. Flygare, J. Chem. Phys., 1974, 60, 1761. C. Thomson, Chern. Phys. Letters, 1974, 25, 59. M. Fouassier, M.-T. Forel, J . Bouix, and R. Hillel, J. Chirn. phys., 1973, 70, 1518. H. S. Randhawa, Z . phys. Chem. (Frankfurt), 1974, 89, 320. K . Brendhaugen, E. W. Nilssen, and H. M. Seip, Acta Chem. Scund., 1973, 27, 2965. K.Johansen, E. W. Nilssen, H. M. Seip, and W. Siebert. Acta Chem. Scund.. 1973, 27, 30 15. H. Noth and U. Schuchardt, Chem. Ber., 1974. 107, 3104. J . Kroner, D. Nolle, and H. Noth, Z. Naturforsch., 1973, 28b, 416.

Elements of Group 111 145 Y = S or Se) have been prepared.2481.r. spectra and n.m.r. ( R = Me only) spectra were reported. The shifts in u(P-Y) upon co-ordination are very large for nsn-bridging ligands, indeed almost as large as when these ligands act as bridging species. The spectral data on the B-Y bond indicate that this increases in strength as the atomic weight of X increases. Thioboranes PhnB(SR)3-n ( n = 0 , 1, or 2) may be obtained from the interaction of a lead thiolate and the corresponding chloroborane:

Lr., mass, and "B n.m.r. spectra were reported for the compounds with R = Me, Et, or Pr".'49

Boron Halides.-An cab initio MO calculation on BF2, using a nearHartree-Fock atomic basis, predicts a bond angle of 120" and a bond length of 1.22A for the XZ(A,)ground state.'" Similar calculations (using a restricted Hartree-Fock model) on the excited states of BF, suggest that some of these may have very unusual geometries (e.g. angles of 46", 6O0).'" The overlap populations are positive and hence these states are likely to exist (unlike some similar apparent states for NH,). An analysis of the rotational constants of SiF,BF, derived from the microwave spectrum leads to a very large value for the Si-B bond length (2.04*0.03 This is greater than the value expected for a single bond and is consistent with the very low barrier to rotation (1.9k0.8 cal mol-') about this bond. The molecules B4F4 and B4CL have been studied by ab initio SCF methods, using a minimum basis set of Slater The results suggest that there is more .rr-back-donation for B4F4 than for B4CL, although expanded-basis-set calculations may be necessary before such conclusions can be regarded as definite. A relative acidity scale based on the proton shifts of the diethyl etherates of BCl, and BF, has been extended to a number of trifluorovinylchlorob o r a n e ~ . 'The ~ ~ following sequence was observed, with approximate values as shown: BC1, > C,F3BC12> (C2F,),BC1> (C,F,),B > BF, (100)

(92)

(82)

(74)

(63)

These are consistent with a lack of interaction between the .rr-electrons of the trifluorovinyl group and the boron pz -orbital.

"' P. 249

25u 2s1

252 257 2s4

M. Boorman and D. Potts, Canad. J. Chem., 1974,52, 2106. R. H . Cragg, J. P. N. Husband, and A. F. Weston, J . Inorg. Nucleur Chem., 1973, 35,3685. C. Thomson and D. Brotchie, Theor. Chim. Acta, 1973, 32, 101. C. Thomson and D. Brotchie, Mol. Phys., 1974, 28, 301. T. Ogata, A. P. Cox, D. L. Smith, and P. L. Timms, Chem. Phys. Letters, 1974, 26, 186. J . H. Hall jun., and W. N . Lipscomb, Inorg. Chem., 1974, 13, 710. N. Walker and A. J . Leffler, Inorg. Chem., 1974, 13, 484.

146 Inorganic Chemistry of the Main - group Elements Preliminary results of a ”C n.m.r. study of BF, and BC1, complexes with a number of ethers have been reported.255At low temperatures it was possible to detect separate signals for free and co-ordinated ether molecules. The 13C shifts at the a-carbon are to lower field in the complexes, and decrease in the order: THF> E t 2 0> P r 2 0 Bu,O. A b initio calculations of the heats of formation of a series of BF, addition compounds (with, for example, NH,, H 2 0 , F-, CO, C1-, H2S, Ne, or Ar) reflect the trends in the experimental data, where these are available.256 Complexes which are unknown (Ne, Ar, H2S, and CO) all have negative heats of formation, but complex formation is not favoured by the entropy changes. The adduct (tetramethylurea),BF, contains (when prepared in the absence of solvent) some [(tmu),BF,]’BF;, which is detected by n.m.r. experim e n t ~ . ~The ~ ’ mixed halide adducts (tmu),BF,Cl and (tmu),BFCl, are formed when the BF, and BCl, adducts are mixed. The former can be used to generate larger amounts of [(trnu),BF2]+ uia nucleophilic attack of tmu on the adduct, with displacement of C1-. Kinetic studies of the heterogeneous reaction: =ZI

reveal a slowing-down, and even a cessation of reaction, as the reaction progresses, especially at higher temperatures. This may be attributed to an agglomeration of the reaction product at the SrF, s u r f a ~ e . ~ ~ ~ . ~ ’ ~ Thermodynamic data for the negative ions of boron and aluminium fluoride, e.g. MF; and MF,, have been evaluated from effusion mass spectrometric measurements over the temperature range 1100-1 900 K.’“” Electron affinities for BF, and AlF, are 50.7*3 and 53.1 *t3 kcal mol-’, respectively. The influence of excess H’ (from H,SO,) upon the rate of reaction of H,BO,+HF (to produce HBF,) has been interpreted in terms of the following reaction mechanism:261 H,BO,

+ 3HF+

HBF,(OH) + 2H,O (very fast)

HBF,(OH) + H+& (HBF;OH2) (HBFiOH,) + HFk-. HBF,

”’

+ H,O

A. Fratiello, G. A. Vidulich, and R. E. Schuster, J . Inorg. Nuclear Chew., 1974. 36, 9.3. R. M. Archibald. D. R. Armstrong, and P. CT.Perkins, J.C.S. Faraday 11, 1973, 69, 1793. ”’ J . S. Hartman and G. J . Schrobilgen, Inorg. Chew., 1974. 13, 874. ”’ A. Boisselier, F. Caralp, and M. Destriau. Bull. Soc. chim. France. 1Y74, 1233. 2 4 y A. Boisselier. F. Caralp, and M. Dcstriau, Bull. Soc. chirn. France, 1974, 1735. O ‘’ R. D. Srivastava, 0. M. Uy. and M . Farber, J.C.S. Faraday 11. 1974. 70, 1033. ”l M. P. Menon, J . Inorg. Nuclear Chew., 1973, 35, 4183. 776 -

Elements of Group 111

147

Ionization energies of the electronic valence levels of BF, have been obtained by X-ray electron spectroscopy.262 The RbF-RbBF, system is a simple eutectic, with a eutectic composition of 68.5 mole% RbBF,, and a melting point of 442 f2 oC.’63 Complexing of BF, with solutions containing MF, ( M = N b or Ta) gives chiefly a disproportionation reaction yielding M,F;, :264 BF, + MF, 6 BF, MF, + MF; BF, + BF,

+ MF,

M2F;, B,F;

X-Ray diffraction and transition entropy data for the high-temperature phases of NH: and K’BF; have been interpreted in terms of an approximate structure for these systems.26s In this the anions are distributed between two sets of statistically equivalent orientations in the skeleton of the positive ions, in a similar manner to that proposed for univalent metal perchlorates. The crystal structure of Cu(BF,)(PPh,), reveals that the BF; ion is weakly co-ordinated to the Cu via a Cu-F-B interaction.266Relevant structural data are summarized in Figure 21. The Raman spectrum of the complex was recorded and compared with that of CuCl(PPh,),. Characteristic BF; bands were seen at 765 (A, stretch) and 355 cm-’ (E, def.), with a band at 176 cm-’ assigned to v(CuF). The low value of the last agrees with the weak interaction deduced from the Cu-F bond length. An i.r. study of the mixed boron trihalide adducts of carbonyl donors (ethyl acetate and benzophenone) shows that the mixed adducts do indeed possess Lewis acidities intermediate between those of the corresponding BX, ~ystems.’~’ “B and 19F chemical shifts and “B-”F coupling constants of boron trihalide adducts have been shown to behave in accordance with the concept of ‘painvise additivity’.’68 Hard and soft donor atoms yield very different donor-halogen pairwise interaction parameters, which can be diagnostically useful when donor ligands contain more than one possible donor atom. The i.r. and Raman spectra of BX, (X = F, C1, Br, I, or H) complexes of 1,4-diazabicycl0[2,2,2]octane, dabco, suggest that these (dabco)(BX,), complexes have D,, (not D,) Analogous quinuclidine complexes gave spectra which could be assigned on the basis of C1,symmetry. 262

263 264 265

266 267

268 269

V. 1. Nefedov, Yu. V. Kokunov, Yu. A. Buslaev, and M. A. Porai-Koshits, Russ. J. Inorg. Chem., 1973, 18, 637. L. 0. Kilpatrick and C. J. Barton, J. Inorg. Nuclear Chern., 1974, 36, 725. S. Brownstein, J . Inorg. Nuclear Chem., 1973, 35, 3567. K. 0. Stromme, Acta Chem. Scand., 1974, 28A, 546. A. P. Gaughan jun., Z . Dori, and J. A. Ibers, Inorg. Chem., 1974, 13, 1657. J. S. Hartman and R. R. Yetman, Canad. J . Spectroscopy, 1974, 19, 1 . J. S. Hartman and J. M. Miller. Inorg. Chern., 1974, 13, 1467. J . R . Mcdivitt and G . L. Humphrey, Spectrochim. Acta, 1974, 30A, 1021.

148

Inorganic Chemistry of the Main-group Elements

Figure 21 Perspective view of the inner co-ordination sphere of Cu(BF,)(PPh,),. The distances and angles refer to a chemically averaged (Reproduced by permission from Inorg. Chem., 1974, 13, 1657) The vapour-pressure isotope effect of BC1, (loB/llB) as observed by Rayleigh distillation appears to be of the wrong sign according to the theory of isotope effects in condensed systems (that for ”Cl/”Cl is satisfactory, however) .270 1.r. and Raman spectra of polycrystalline BX, (X = C1, Br, or I) at 80 and 18 K were analysed to give values for the lattice vibration wave number^.^^' CNDO molecular wavefunctions have been used to calculate dipolemoment derivatives for BCl,.272These were compared with experimental values from i.r. intensities. The latter set, having all signs negative, was preferred. The reaction of elemental boron with GeCl, gives BCl,+Ge at 550600 “C, BCl, + GeCl, at 600-800 “C, and BCl, + Ge’ chloride at 9001100 0C.273No evidence was found for the formation of BC1 at any stage. Complex formation involving acetic anhydride has been investigated in 27(1

. G. Jancsh. Her. Bunsengesellschuft phys. Chern.. I 9 7 4 78, 63X. 0. S. Binbrek, N. Krishnamurthy, and A. Anderson, J. Chem. Phys., 1974, 60, 4400. 272 R. E. Bruns and P. M. Kuznetsof, J . Chem. Phys., 1973, 59, 4362. 2 7 3 G. M . Gabrilov and V . I. Evdokimov. Russ. J. Inorg. Chern., 1973. 18, 915.

’’’

Elements of Group III

149

liquid SO, Among the compounds isolated were 1:1 adducts with BX,, A K , (X = C1 or Br), and InCl,. SbCl, also gives a 1: 1 adduct. Simple donar-acceptor complexes are indicated (by conductivity measurements, mol. wt. determinations, and i.r. spectra) for the majority of the compounds, but there is evidence for the acetylium ion in the cases of AlBr, and SbCl,. BCl, reacts with a number of chlorides of univalent cations to give tetrachloroborates MBC1,: the degrees of conversion are shown in Table 3 .27s

Table 3 Degrees of conversion into MBC1, Halide KCl RbCl CSCl NMe4C1 NEt,Cl

Solvent CHC1, BCl, 50.0 76.3 72.5 61.1 81.9 85.2 88.9 95.7 91.9 97.2

A convenient synthesis of B,CL, has been reported, employing a novel vapour pump.276 The results of an all-electron a b initio MO calculation predict a staggered (DZd) configuration for B2C14,with a barrier to rotation of 1.48 kcal mol-'. Results for B,F, indicate a similar configuration with a much reduced barrier (0.39 kcal mol-'). Further calculations indicate that B4C1, is more stable with respect to four BCl units than is B,F, to four BF.277 The standard enthalpies of formation of o - and p-tolyldichloroboranes have been determined from a thermochemical study of their oxidative hydroly~es."~Boron-carbon bond energies were calculated from these: o-MeC6H4BCl, 463 f 10, p-MeCsH4BClz 504* 10, and PhBC1, 508* 10 kJ mol-', for E(B-C). The value for the para-isomer is essentially identical to that for the PhBC12,but the steric effects of the o-Me group are such as to lead to a significant decrease in E(B-C) because of twisting of BCl, out of the ring plane and consequent loss of pm-p,, character in the B-C bond, Studies of the interaction of BBr, vapour with boron show that the reported transport of B in BBr, vapour is due to thermal dissociation of the latter.279 Raman spectra of mixtures of BBr, and PBr, contain bands characteristic of PBr: and BBr;.28" An emission spectrum of BI in the region 5700-6215 A has been 274

275

276 277 278 279

K. C. Malhotra and D . S. Katoch, Austral. J . Chem., 1974, 27, 1413. K. V. Titova, I. P. Vavilova, and V. Ya. Rosolovskii, Russ. J . Inorg. Chem., 1973, 18,597. J . P. Brennan, Tnorg. Chem., 1974, 13, 490. M. F. Guest and I. H. Hillier, J.C.S. Faraday I I , 1974, 70, 398. A. Finch, P. J. Gardner, N. Hill, and K. S. Hussain, J.C.S. Dalton, 1973, 2543. B. A. Savel'ev, V. A. Krenev, and V. I. Evdokomov, Russ. J . Inorg. Chem., 1973,18, 748. M.-C. Deneufeglise, P. Dhamelincourt, and M. Migeon, Compt. rend., 1974, 278, C, 17.

150

Inorganic Chemistry of the Main - group Elements observed,**' which can be assigned to the a311'-,X'C' system. Flash photolysis of BI3 gives two band heads (3489.3, 3491.0A) due to the a 'II + X'c' transition of BI.

Boron-containing Heterocycles.-The enthalpies of adduct formation between pyridine, 2-picoline, 4-picoline, or 2,4,6-collidine and a number of heterocyclic boron derivatives (2-Br- or 2-organo- 1,3,2-dihetero-borolans, -borinans, and -boroles) have been measured.282The presence of Br greatly increases the Lewis acidity of the B atom. A number of methods have been devised for the preparation of the new compound H,B(NMe,),Al(BH,),, e.g. the reaction of excess B,H, with Et,O solutions of Al(NMe,),, HAI(NMe,),, or [H,B(NMe),],AlH. Characterization of the compound leads to the postulated structure (34).'"

(34)

Tris(mono-n-alkylamine),B,H, adducts decompose thermally by the following scheme, via p -monoalkylaminodiboranes(6), with the final formation of NN'N"-trialkylborazines, polymeric solid boranes, (BH),, and H2:284 3 3(B,H9,3NHZR) + (35) +- (HZB-NRH), (35) +-2(HBNR), 3

- (BHZNHR), -+

6 +n (BH), + 12H2

(HBNR), + 3Hz

A series of N- or B-functional derivatives of 1,2,4-triaza-3,5-diborolidines (36), where R', R 2 = H , Me; R 3 = H , Me, or B(NR,),; R 4 = M e , C1, R'

N N '

2x 1

/R2

I

\

J . Lebreton. J . Ferran, A. Chatalic, D. Iacocca, and L. Marsigny, J. Chim. phys., 1974, 71, 5x7. '" M . Wieber and W. Kiinzel, Z. anorg. Chem., 1974, 403, 107. zx3 P. C. Keller, J . Amer. Chem. SOC., 1974, 96, 3073. 2x4 A. F. Zhigach, V. T. Laptev, A. B. Petrunin, V. S. Nikitin, and D. B. Bekker, Russ. J. Inorg. Chem., 1973, 18, 1249.

151 Elements of Group I11 Br, NMe2, or SMe, have been p~epared."~A typical reaction leading to such a system is:

' = SMe) 2B(SMe),+ MeNHNHMe+ MeNH2+ (36; R' = R2= Me, R Photoelectron spectra have been reported and largely assigned for five tetra-azadiborines (37; X = Me, C1, MeS, MeO, and MezN).286Orbital energies calculated using the C N D 0 / 2 approach agree quite well with the observed ionization energies.

Two more efficient methods for the synthesis of bis(F-dimethylamino)triborane(9) (38) have been described, viz. the reaction of Me,NHBH,NMe,BH, + K (in ether solvents), to give KMe,NBH,NMe,BH,; treatment of this with excess B2H, forms the desired Alternatively, HB(NMe,), + B2H, forms this species directly. Detailed "B n.m.r. spectroscopic studies have been made of the compound and of the courses of a number of its reactions. A new heterocyclic system (39) containing B and Sn has been prepared, thus: Et,NB(C=CMe), + Me,SnH, + (39). The "B chemical shift is at -33.7 p.p.m. from BF,,OEt, at 32.1 MHz, and v(C=C) bands were seen at 1590, 1560 cm-'.288 The (1-methy1borinato)cobalt complex (40) may be prepared by the A number of other reaction of the known (41) with diphen~lacetylene.~~~ closely related complexes have also been de~cribed.'~'

I

I co

phm:: I

Ph

285

**' 287 28R

289

Ph HN/~\NH

I

MeSi,

I

,SiMe, N H

D. Nolle, H. Noth, and W. Winterstein, Z. anorg. Chern., 1974, 406, 235. J. Kroner, D. Nolle, H. Niith, and W. Winterstein, Z. Naturforsch., 1974, 29b, 476. P. C. Keller, J: Amer. Chem. SOC.,1974, 96, 3078. €3. Wrackmeyer and H. Noth, Z. Naturforsch., 1974, 29b, 564. G. E. Herberich and H. J. Becker, Z. Naturforsch., 1973, 28b, 828. G. E. Herberich and H. J. Becker, Z. Naturforsch., 1974, 29b, 439.

152

Inorganic Chemistry of the Main -group Elements Phenyldichloroborane reacts with (Me,SiNH), to give (42), and related species, depending upon the ratio of the reactants.291 Previous X-ray data (J. G. Haasnoot, G. C. Verschoor, C. Romers, and W. L. Groeneveld, Acta Cryst., 1972, B28, 2070), which indicated alternating B-N bond lengths in hexachloroborazine, have been reinterpreted, in conjunction with semi-empirical MO calculations.292The data were shown to be consistent with the presence of a regular hexagonal ring. Use has been made of a strong substituent effect in borazine chemistry to produce 2,4-dichloroborazine in a specific, two-step ~ y n t h e s i s . ~The ' ~ first stage involves the reaction of Cl,B,N,H,+NMe,H to produce only C1,(NMe2)B,N3H,, which subsequently reacts with B,H, in E t 2 0 to form HCl,B,N,H,. A modification of the standard C N D 0 / 2 MO calculation, in which pairs of atoms associated with the same or different molecules are differentiated, leads to reasonable results for n-.rr-type molecular complexes.294It was suggested that benzene-borazine (stabilization energy 2--5 kcal mol-') and borazine-borazine (5-18 kcal mol ') can exist in the ground state, the molecules being arranged symmetrically in parallel planes. The unsymmetrical B-substituted borazine derivatives H(X)(Y)B,N,H,, where X = C1, Y = OCN; X = C1, Y = CN; X = CN, Y = OCN; X = OCN, Y = OCN; X = CN, Y = CN, have been prepared by the reaction of the appropriate B-substituted chloroborazine with an Ag' It was found that H atoms in B-substituted borazines, unlike those in H3B3N3H3,are inert to attack by an Ag' salt, giving the first evidence for a substituent effect in borazine chemistry. Considerations of magnetic susceptibilities and 'H n.m.r. data suggest that B-tribromo-, B -trifluoro-, and B -trialkoxy-borazines can be considered as aromatic Their aromatic characters, however, are in the sequence: B-tribromo- > B -trialkoxy- > B -trifluoro-derivatives. Comparison of spin-spin coupling constants through -5, 6, or 7 bonds between protons in benzene derivatives and borazines indicates that there is a relatively weak transmission of spin density via the presumed n-electron system of bora~ine.*~' 'H n.m.r. spectral data have been reported for hexamethylborazine, B monoethylpentamethylborazine, BB '-decamethylbiborazine, and B -pentamethylphenylpentamethylb~razine.~~~ A synthesis of deuterium-labelled hexamethylborazine, with CD, groups

'" H . Noth,

W. Tinhof, and T. l a e g e r . Chem. Ber., 1973, 107, 3 1 13. M . S. Gopinathan, M . A. Whitehead, C . A . Coulson, J. R. Carruthers. and J . Kollett, Actu Cryst., 1974, B30, 731, 1650. zy3 0. T. Beachley jun., and T. R. Durkin, Inorg. Chem., 1974, 13, 1768. 294 F. Grein and K. Weiss, Theor. Chim. Acta, 1974, 34, 315. 2 y 5 0. T. Beachley jun., Inorg. Chem., 1973, 12, 2503. 29h G. Cros a n d J.-P. Laurent, J . Chim. phys.. 1974, 71, 802. 297 J . B. Rowbotham and T. Schaeffer, Canad. J . Chem., 1974, 52, 489. '" J. L. Adcock and J . J . Lagowski, J. Organometallic Chem., 1974, 72, 323.

'*

Elements of Group I11 153 attached to the B, has been described,299and a pyrolysis carried out at 500 "C. The products were investigated mass-spectrometrically, showing that H-containing methanes predominate over those containing D. This indicates that the rate of homolytic rupture of N-C bonds is greater than that for B-C bonds. A number of (substituted borazine)chromium tricarbonyl complexes have been prepared.30"The chief change in the vibrational spectrum of the ligand upon complexation is a decrease in the wavenumbers of the band associated with B-N stretching, e.g. in (Me,N,B,Me,Ph)Cr(CO), this is at 1371 cm-', compared to 1423 cm-' in the free ligand. N-Methyltetrahydro-2,1 -borazarene may be partially dehydrogenated to N-methyl-2,l-borazarene (43). This could only be identified massspectrometrically, as it is highly reactive, being quite unlike benzene, and more akin to a polarized butadiene derivative.,"'

Tris(amin0)boranes react readily with aliphatic NN'-dialkyldiamines in an inert solvent, giving a 2-amino- 1,3,2-diazaboracycloalkane(44): (Me2N),B + (RHN)2(CH2),-+ 2Me,NH+ (44) ( R = M e or Et). When R = H , however, a polycycliborazine (45) results, e.g.302 (Me,N),B

+ (H2N),(CH2),-+3Me2NH+(45)

173,2-Diazaborolines (46) may be prepared by the dehydrogenation (using Pd/C) of saturated derivatives, R' = Me, R2= Ph or CMe,, or R' = H, R2= Ph.,03 This heterocyclic system is isoelectronic with the cyclopentadienide ion, and some data ( e . g U.V. spectra) suggest that there are comparable degrees of electron delocalization in the two cases. The same conclusions follow from a consideration of their H e (I) photoelectron A new boron-containing heterocycle, 1,173,3-tetramethyl-173-diazonia2,4-diboratocyclopentane (47), has been prepared by the reaction of 299

30" 'O'

'02

303 304

N. A . Vasilenko, A . S. Teleshova, and A . N . Pravednikov, J . Gen. Chem. (U.S.S.R.),1973, 43, 1114. J . L. Adcock and J . J . Lagowski, Inorg. Chern., 1973, 12, 2533. H. Wille and J . Goubeau, Chern. Ber., 1974, 107, 110. R. H. Cragg and M. Nazery, Inorg. Nuclear Chem. Letters, 1974, 10, 481. K. Niedenzu and J . S. Merriam, Z. anorg. Chern., 1974, 406, 251. J . Kroner, H. Noth, and K. Niedenzu, J. Organornetallic Chern., 1974, 71, 165.

154

Inorganic Chemistry of the Main -group Elements HN

I

HC=CH

i \

R1-vM I

R2

bis(trimethy1amino)boronium iodide with Na-K alloy in 1,2dimethoxyethane.'"' I.r., 'H and "B n.m.r., and mass spectral data were reported.

\

I

R1

N-CH2R'

H,B -NMe,

I

Me

(47)

(48)

The amine-boranes of 3,4-dihydro-2H- 1,3-benzoxazines are unstable t o heat, producing 4H- l-oxa-3-azonia-2-boratonaphthalenes,i.e. (48), where R ' = M e O , R Z = P h , PhCHz, or H.306 A new five-membered heterocyclic species containing Si and B has been prepared by the sequence of reaction^:^"' Ph,Si-SiPhz Ph,Si-SiPh,

I

I

Ph,Si-SiPh,

I . SiPh, I A PhzSi I Li

t Li

Ph'Si-SiPh, C12BNMe2+

Ph,Si 'B'

I

SiPh, NMe,

The crystal structure of (49) has been determined.308The crystals are orthorhombic, belonging to the space group Pna 2 , . The following bond lengths were reported: B-C 1.632(8), B-0 1.506(7) and 1.556(8), N-0

")'

B. R. Gragg and G. E. Ryschkewitsch, J. Amer. Chem. Soc.. 1Y74. 96, 1717. E. Lyle and D. A. Walsh, J . Organornetallic Chem., 1974, 67,363. E. Hengge and D. Wolfer, J. Organometallic Chem., 1974, 66,413. S. J . Rettig, J . Trotter, and W. Kliegel, Cunad. J. Chem., 1974, 52, 2531.

'"'R. '07 'Ox

Elements of Group I11 155 1.409(5), C-0 1.378(9), and C-N 1.467-1.509(7-10) A. The ring possesses a distorted, half-chair conformation. Mass spectra of numerous boron-chelate complexes of pyridines and quinolines (five-membered chelate rings) and their N-oxides (six-membered chelate rings) have been recorded.309 By analogy with the P-diketonates, the products (50) that result when (acy1amino)dialkylboranes RiBNHCOR' form complexes are considered as chelates of the ligand N-acylamidine."" Spectroscopic data have been presented and reactions described in which both retention and degradation

of the chelate ring occur. Acetic acid can be used to replace one of the R groups on boron by an OC(=O)Me group, with preservation of the chelate structure. Syntheses and some characteristic reactions have been reported for some derivatives (51); when M = Si, R' = Me, Et, Pr, or Ph, R2= Me; or M = Sn, R' are as before, R2= Bu or Ph.3" BB -Bis-(p-fluoropheny1)boroxazolidine(52) forms orthorhombic crystals,

space group P2,2,2,."' The five-membered ring is in the half-chair conformation, with the following (mean) bond lengths: B-N 1.652(4), B-0 1.471(4), C-N 1.491(4), and C-0 1.418(4)A. A number of new five- and six-membered heterocycles have been pre' ~ are pared, e.g. (53); these are formally cyclized amino-acid b o r a n e ~ . ~All air-stable, volatile solids, characterized by the usual physical methods. The crystal structure of (54)has been determined.314It is orthorhombic, belonging to the space group Pnrna, and the B-0 and B-C distances are 1.394 and 1.537 A, respectively. ?'" ?"'

?"

3'1 314

E. Hohaus and W. Riepe, Z . Naturforsch., 1973, 28b, 440. V. A. Dorokhov, L. I . Lavrincivich, M. N. Bochkareva, V. S. Bogdanov, and B. N. Mikhailov, J. Gen. Chem. (U.S.S.R.), 1973, 43, 1106. A . B. Goel and V. D. Gupta, J. Organometallic Chem., 1974, 77, 183. S. J . Rettig and J . Trotter, Acta Cryst., 1974, B30, 2139. N. E. Miller, Inorg. Chem., 1974, 13, 1459. F. Zettler. H. D. Hausen, and H . Hess, Acta Cryst., 1974, B30, 1876.

Inorganic Chemistry of the Main-group Elements

156

/ O V 0

Substituted derivatives of 2-phenyl- 1,3,2-dioxaborolans undergo electron-impact-induced rearrangements, giving hydrocarbon ions (detected mass-spectrometrically) .315 The compound (55) is produced as the major species from a gas-phase reaction of 1,l-dimethyldiborane + 0,.3'" It has been characterized by a

0-0 (55)

variety of physical techniques, which suggested that the unexpected stability of the molecule may be due to partial aromatic character. The related compound containing only one Me group is produced by the reaction of methyldiborane and 0, above 150 "C."' Semi-empirical MO calculations on H,B,O, agree with some experimental data which indicate that the preferred structure is (56) rather than (57).31* For the sulphur analogue (X = H, Pr", or Br) the calculated energy levels are close to those found from their electronic spectra. H

HB

/8\ \A/

0 0 0

H

Similar calculations on these types of ring system (both B-0 and B-S) suggest that there is a high degree of conjugation in all cases.319Surprisingly, the degree of conjugation was found to be similar for both types, although this may not be a significant result at this level of approximation. 2-(Trimethylsi1oxy)- 1,3,2-dioxaborolans and -borinans are formed by cleavage of corresponding trialkyl- tin or -germanium derivatives by

'Ih 317 71H

'Iy

H . Cragg. J . F. J . Todd, and A. F. Weston. J. Organornetallic Chem.. 1974, 74, 385 Barton and J . M. Crump. Inorg. Chem., 1973, 12, 2252. Barton, J . M. Crump, and J . BLWheatley, J. Organornetallic Chem., 1974, 72, C1. Zahradnik, Z. Slanina, and P. Carsky, Coll. Czech. Chem. Comrn., 1974, 39, S7. 0. Gropen and P. Vassbotn, Acta Chern. Scand., 1973, 27, 3079. R. L. L. R.

Elements of Group 111

157

Me,SiCl. The products are ( 5 8 ) , where R = -CMe2-CH2-CHMe-, -CMe,-CMe,-, -CH,-CH,-CH,-, or -CH2-CHMe-.320 Reactions producing (59) (with X = H, R = CH,CH, or CMe2CH2CHMe;

X=SiMe,, R=CH,CH,) and (60) (with the same X and R) have been rep~rted.~” The compounds (61; R = Me or Bu; X = CMeKHzCHMe, CMe2CMe2, or CHMeCH,) have been prepared from the dialkyltin oxide, H3B03,and the

(61)

appropriate glycol.322A number of spectroscopic properties suggest that they are dimeric. A large number of 2-substituted 4H-1,3,2-benzodioxaborinshave been prepared by a number of different reactions, e.g.:323

Several examples of (62), (63); and (64) have been d e s ~ r i b e d . ~ ~ ~ , ~ * ~ Pure samples of the cyclic compounds (BSX),, where X = C1, Br, or I, have been prepared in the absence of organic solvents by the following reactions: (BSCI),, dissolution of (BSSH), in liquid BCl,; (BSBr),, action of H,S on liquid BBr,; (BSI),, passing H,S over solid BI,.3’6 They were

(62) 320

3 2’

”* 323

324

325 326

(63)

(64)

S. K. Mehrotra, G. Srivastava, and R. C. Mehrotra, Synth. React. Inorg. Metal-org. Chem., 1974, 4, 27. G. Srivastava, J . Organometallic Chem., 1974, 69, 179. S. K. Mehrotra, G. Srivastava, and R. C. Mehrotra, J . Organometallic Chem., 1974, 65, 367. R. H. Cragg and M . Nazery, J.C.S. Dalton, 1974, 162. R . H. Cragg and M. Nazery, J.C.S. Dalton, 1974, 1438. B. Asgaroulardi, R. Full, K.-J. Schaper, and W. Siebert, Chem. Ber., 1974, 107, 34. R. Hillel. J . Bruix, and M.-T. Forel, Bull. SOC. chim. France, 1974, 83.

158 Inorganic Chemistry of the Main- group Elements characterized by X-ray powder-diffraction, “B n.m.r., i r . , and Raman spectra. Some vibrational assignments have been made, and also for (BSSH), and (BSSD),. Triphenylborthiin (65) possesses considerable stability associated with the ring structure, as revealed by a comparison of its mass spectrum with that of 2,4,6-triphenyl- 1,3,5-trithian. It is that this could possibly be due to charge delocalization in the borthiin ring.

PhB,

,BPh S

Metal Borides.-Chemical and ESCA studies on hydrogen adducts of cobalt and nickel borides are consistent with the formulations (CozB),H3 and (NizB)zH,.328 The structures of CeCo,B, Ce3CollB4,and Ce2C07B3are built up from layers of composition CeCo5 alternating with 1, 2, or 3 layers of composition C ~ C O ~ B ~ . ~ ’ ~ The new ~ - b o r i d e sM,Re,B (M = Z r or Hf) and Hf90s4B have been prepared and identified.”’ IrB--1.35 has a crystal structure that may be described in terms of puckered layers of B and puckered double layers of Ir which also contain B atoms in trigonal-prismatic holes. There is no three-dimensional B network.331 Biborides of holmium and thulium have been prepared from the elem e n t ~They . ~ ~belong ~ to the same class of structures as AlB,. The structures of HoCozB2,PrCo,B,, and Y bCo,Bz have also been determined.333 is The crystal structure of ‘BeB3’, shown analytically to be BeB3.05+0.05, hexagonal. The lattice structure is very complex, although based on icosahedral B,, The new complex ternary borides ThMB,, with M = Mo, W, V, or Re, have been obtained and shown to be isotypic.”’ A band model for the mechanism of conduction of electricity in EUB, and YbB, has been 127 ?ZX

’” 330 11 I

171

333 314

R . H. Cragg and A. F. Weston, J.C.S. Chem. Comm., 1974, 22. P. C. Maybury, R. W. Mitchell, and M . F. Hawthorne. J.C.S. Chem. Comm.. 1973. 534. Yu. B. Kuz’ma and N. S. Bilonizhko. Societ Phys. Cryst., 1973, 18, 137. P. Rogl a n d H. Nowotny, Monatsh., 1973, 104, 1497. T. Lundstriini a n d L.-E. Tergenius. Acra C‘hem. Scund., 1973, 27, 3705. J . Bauer and .I. Debuigne. Compt. rend.. 1973, 277, C, 851. P. Rogl, Monatsh., 1973, 103, 1623. R.Mattes, H. Neidhard, FT. Rethfeld. and K. F. Tebbe. Inorg. Nuclear Chem. Letters, 1973, 9, 1021.

335 136

P. Rogl and H. Nowotny, Monatsh., 1974, 105, 1082. J. B. Goodenough, J.-P. Mercurio, J. Etourneau, R. Naslain, and P. Hagenmuller, Compt. rend., 1973. 277, C, 1239.

Elements of Group I11

159

Electron-beam microanalysis shows that the homogeneity range of the non-stoicheiometric phase EUI-xB6extends from x = 0 to x = 0.10.337 'Erbium hexaboride' is in fact Er,&&.,B6, having the CaB6 The intra-octahedral B-B distance is 1.751k0.039 A,with the shortest Er-B distance 1.622 f 0.008 A. Magnetic measurements have been reported for the 7-borides Ir,,-,Fe, B6 (x = 8-15) and for solid solutions Co,-,FeB, (Ni, Co)& and (Ni, Fe)3B.339 Entropies of fusion have been measured for Zro6Yo,B,,, ErB1,, and ~JB,.~"' Aggregates of single crystals of CUB,, have been produced by cooling Cu-B mixtures from 1500°C to room temperature.341 They are rhombohedral, with a structural unit Cu4.,BIo5. Crystals of copper boride have a variable composition, depending on the temperature of crystallization, ranging from CUB,^.^ at 1700 "C to CUB^^.^ at 1300°C.342

2 Aluminium General.-The species M,Al (M=Gd, Tb, Dy, Er, or Tm) are metamagnetic, and can be divided into two classes. The first 3 possess a NCel temperature of ca. 5 0 K , the remainder having one of only a few K.343 Two new intermetallic phases containing A1 have been reported, UzCu9A1and UCu3.,Al,.,; both are derived from the binary phase U C U ~ . ~ " ~ Crystals of the phase ZrFe,.,Al,., belong to the space group 14/mcm, with a = 8.37, c = 9.98 A.345 A study of the Li-A1 phase diagram has revealed the existence of another phase, Li3A1,.346This may be isolated and shown to form rhombohedra1 crystals, of space group ~ 3 m . The structures adopted by the binary compounds of the Group I or I1 metals with elements from Groups 111-VI, the so-called Zintl-phases, have been reviewed, and the bonding in such species has been discussed in terms of the transition between metallic and ionic bonding.'"' The A1 K a and K@1,3X-ray emission spectra of a number of compounds have been reported, viz. alumina, microcline, kyanite, cryolite, A1F3,AlCl,, topaz, and A1 acetylacetonate and 8-hydroxy-quinolinate, as well as for the '" K. Schwetz and A. Lipp, J. Less-Common Metals, 1973, 33, 295.

-'''M. C. Nichols, 33y

"')

R. W. Mar, and Q. Johnson, J. Less-Common Metals, 1973. 33, 3 17.

R. Sobczak, Monatsh., 1974, 105, 1071.

R. W. Mar and N. D. Stout, High Temp. Sci., 1974. 6, 167. I . Higashi. Y. Takahashi, and T. Atoda, J. Less-Common Metals, 1974, 37, 199. '42 J.-P. Diton, G. Vuillard, and T. l.u,ndstrom, Compt. rend., 1974, 278, C, 1495. 117 B. Barbara. M.-F. Rossignol, and E. Siaiid. Compf. rend., 1974, 278, €3, 513. 344 Z. Bla5ina and A. Ban. Z . Naturforsch.. 1973, 28b, 561. 745 G. Athanassiadis, M. Dirand, and L. Rimlinger. Compt. rend., 1973, 277, C, 915. "'K.-F. Tebbe, H. G . von Schnering, B. Riiter. and G. Rabeneck, Z. Naturforsch., 1973, 28b, 600. 347 H. Schafer, B. Eisenmann, and W. Muller, Angew. Chem. Internat. Edn., 1973, 12,694. 34 1

160

Inorganic Chemistry of the Main-group Elements

metal it~elf.~"" The relative intensities of the two peaks can be related to bond length and degree of ionic character (Figure 22), while it was also proposed that the fine structure of the K/31,3peak may be due to varying A1 3 p participation in different MO's. Binding energies have been determined for a number of A1 (Al2p, 2s), 3d5,2,3 p 3 d , and Tl(T1 4f7,2,4d5,,) compounds using Ga(Ga 3p312, 3 p 1 A 5193 \

t I

I

I

I

I

1.4

1.6

1.8

2.0

2.2

Intensity ratio

(kp!Ka) ./.

Figure 22 Correlation between the KPIKa peak intensity ratio and the Al0 bond length (Reproduced from J.C.S. Dalton, 1974, 901) Relative chemical shifts were found to be X-ray p.e. proportional to the ratios of the average ionic radii of the metals. A1 may be determined quantitativery by the addition of excess edta, with back titration using Cu" sulphate rather than the Zn solutions used previously.35oN-Salicylidene-2-amino-3-hydroxyfluorenemay be used as a reagent for the luminescence determination of Al."' Aluminium Hydrides.-K[AlMe,SiH,] decomposes to give K[AlMe,H]. The crystal structure of the latter shows that isolated tetrahedral anions are present, with r(A1-H) = 1.730(57),r(A1-C) = 1.995(6) Forms of AlH, soluble in Et,O have been prepared for the first time, by the action of BeCl,, ZnCI,, or H 2 S 0 4on LiAIH,."' The standard enthalpies of formation of some trialkylamine-alanes have been determined.354 C . J. Nicholls and D. S . Urch, J.C.S. Dalton. 1974, 901. G. E. McGuire. G . K. Schweitzer, and T. A. Carlson, Inorg. Chern., 1973. 12, 2450. "') S. Murate, G. Nakagawa, and K. Kodama, Japan Analyst, 1974, 23, 242. "' N. N. Grigoryev, P. Kh. Ioannu, and K. P. Stolyarov, Vestnik Leningrad. Uniz;., Fiz. Khint., 1973, 119. 3 5 2 G. Hencken and E. Weiss. J. Organometak Chern., 1974, 73, 35. "' E. C. Ashby. J. R. Sanders, P. Claudy, and R. Schwartz, J. Arner. Chern. SOC., 1973, 95, 6485. "' K . N. Sernenenko, A. P. Savchenkova, and B. M. Bulychev, Russ. J. Inorg. Chem., 1973, 18, 1251.

Elements of Group I11

161

A detailed study of the reaction of LiAlH, and NaAlH, with BeC1, revealed no evidence for the previously reported Be(AlH,),.355 The interaction of MgC1, and LiAlH, in Et,O yields the following new complex hydrides: Mg(AlH,),,LiAlH, and LiA1H,,3Mg(AlH4)2,nEt20.356 Higher halides of Mo and W can be reduced in high yield in NaAlH, melts, giving a convenient and safe procedure for preparing MoII and W" chlorides and Ca(AlH,), and Mg(AlH,), react with primary amines or organic nitriles, at amine or nitrile/alanate ratios of 3:1, to give mixed polyiminocompounds with -AlH-NRand -M-NR(M = Ca or Mg) An extremely detailed vibrational spectroscopic study has been made of Al(BHJ3 and Al(BD,), (gas, solid, matrix-isolated i.r., liquid, solid Raman).359The data were consistent with a prismatic structure (D3,,),and all 23 fundamentals were assigned. Low-temperature thermal analysis of Al(BH,),-arene (arene = benzene, toluene, 0- and p-xylene, or durene) systems shows that 1: 1 adducts are formed in all cases.36o Direct fluorination of M,AlH, (M = Li or Na) gives high yields of M3A1F6, free from MF and AlF, c~ntamination.~~' AlH, and BeCI, in Et,O react according to the following BeC1, + AlH, + H,AlCl + HBeCl HBeCl+ AlH,

+ BeH,

+ H2A1C1

A number of diethyl ether-dihalogenoalane adducts have been prepared and characterized by X-ray powder diffraction studies. The standard enthalpy of formation of HAlCl,,OEt, was calculated to be -774.29 kJ m~l-'.~~~

Compounds containing Al-C Bonds.-The crystal structure of Rb[AlMe,] reveals that the anion has distorted tetrahedral geometry, with two independent CAlC angles of 106" and 115".364 Similar studies on K[A1,Me6F],C6H6 show that the anion contains a linear, symmetric Al-F-A1 bridge, with r(A1-F) = 1.782(2) Gas-phase electron diffraction has been used to determine the molecular 35s

3s6

357

358 3s9

""

361 362 363

364

36s

E. C. Ashby, J. R. Sanders, P. Claudy, and R. D. Schwarz, Inorg. Chem., 1973, 12, 2860. K. N. Semenenko, B. M. Bulychev, and K. B. Bitsoev, Vestnik Moskou, Uniu., Khim., 1974, 74. W. C. Dorman and R. E. McCarley, Inorg. Chem., 1974, 13, 491. S. Cucinella, G. Dozzi, and A. Mazzei, J. Organometallic Chem., 1973, 63, 17. D. A. Coe and J. W. Nibler, Spectrochim. Acta, 1973, 29A, 1789. K. N. Semenenko, 0. V. Kravchenko, and I. I. Korobov, Doklady Chem., 1973, 211, 549. S. D. Arthur, R. A. Jacob, and R. J. Lagow, -1. Inorg. Nuclear Chem., 1973, 35, 3435. E. C. Ashby, P. Claudy, and R. D. Schwartz, Inorg. Chem., 1974, 13, 192. K. N. Semenenko, V. N. Fokin, A. P. Savchenkova, and E. B. Lobkovskii, Russ. J. Inorg. Chem., 1973, 18, 926. J. L. Atwood and D. C. Hrncir, J. Organometallic Chem., 1973, 61, 43. J. L. Atwood and W. R. Newberry, J. Organometallic Chem., 1974, 66, 15.

162 Inorganic Chemistry of the Main -group Elements structure of (Me2A1Cl),."""The Al-C bond is significantly shorter than the Al-C(termina1) bond in (Me,Al),, and the A1-Cl bond significantly longer than the Al-Cl (bridge) bond in (AlC13)2. Electron-diffraction data on Me,A1(C5H,) were unable to distinguish between four possible molecular models (see Figure 23)."' CNDO/2 calculations, however, suggested a preference for (I), with a barrier to internal

I

I

m

IJL

Figure 23 Molecular models of Me,Al(CsH,) (Reproduced by permission from Acta Chem. Scand., 1973, 27, 3735) rotation of the C,H, ring 5 5 kcal mol-I, and a barrier to exchange of Me groups == 10-20 kcal mol- I . '7A1n.q.r. spectra have been reported for a wide range of monomeric and These have been satisfactordimeric A1 species Me,AIX and (R'R2A1X)2.36" ily analysed in terms of a simplified MO theory. [(C,H,)(CsH4)M~H]2A1,Me5 contains C,H, groups that are h'- to the Mo, and which are also involved, uia the unique C atom, in multicentre bonding to 2 A1 atoms.36yThe third A1 is probably concerned in a Mo-HAI(Me,)-H-Mo bonding unit. Ethylaluminium dibromide with 'H substituted in either the methylene or methyl groups has been prepared by treating A1 powder with a little bromine and either CH,CD,Br or CD,CH,Br."" K. Brendhaugen. A. Haaland, and D. P. Novak. Acta Chem. Scand.. 1071. 28A, 35 A . Drew and A . Haaland. Acta Chem. Scund., 1973, 27, 3735. - I h X M . .I. S. I k w a r . D . B. Patterson. and W. I. Simpson. J.C.S. Dalton. 1973, 23x1. "'' S. J. Rettig. A . Storr. B . S. Thomas, and J. Trotter. Acta Cryst., 1974. B30, 666. "" G. Sonnek and H. Reinheckel, Z . Chern.. 1973, 13, 191. ""

'" D.

Elements of Group 111 163 N.m.r. spectra of the dimethylaluminium-t-butyl titanate system are consistent with the exchange reaction:37* 2Ti[OCMe3], + A1,Me6 + (66) + 2TiMe[OCMe3I3 Diethylaluminium dimethylamide and ethanethiolate, Et,AlX (X = NMe, or SEt), react with diketen, via acyl-oxygen bond cleavage and a 1,3hydrogen shift, to give the chelates (67; X = NMe, or SEt).372 CMe,

I

Me

\

c

Me,

A new synthetic route to bis(dialkyla1uminium) oxides has been developed, involving the condensation of lithium dialkylaluminates with dialkylaluminium Trimethylaluminium and ferrocenylmercury chloride (FcHgC1) react to give a compound formulated as F~Al,Me.,cl.~~~ An unambiguous assignment of the structure was not possible. The vibrational spectra have been recorded and assigned for Me2M(OOPX,) (M=Al, Ga, In, or T1; X = F or Cl).375 4

Compounds containing GI-N or AI-P Bonds.-A set of force constants has been calculated for H,Al- and D3Al-NMe, which reproduce the observed vibrational Electron-diffraction data for Cl,AlNH3, assuming a staggered CJuconformation, may be analysed to give the following molecular parameters: r(A1-N) 1.996~0.019,r(A1-C1) 2.100*0.005 A, and LClAlCl 116.3* 0.4°.37'The Al-N bond length is indicative of strong bonding. The thermal stabilities of Et,XAl-NHMe, and Et,XAl-NH,Bu' follow the sequence X = Et < Cl< Br< I.3781.r. and n.m.r. data have been related to this order, and they show that the adduct stability is chiefly a function of the negative charge density at the a - C atoms. 37'

L. S. Bresler, 1. Ya. Podubnyi, T. K . Smirnova, A. S. Khachaturov, and I. Yu. Tsereteli,

372 373

Doklaily Chem., 1973, 210, 45 1. K. Urata, K . Itoh, and Y. Ishii, J. Organometallic Chem., 1973, 63, 11. N. Ueyama, T. Araki, and H. Tani, Inorg. Chem., 1973, 12, 2218. J. L. Atwood, B. L. Bailey, B. L. Kindberg, and W. J. Cook, Austral. J. Chem., 1973, 26,

374

375 376 377 378

2297. B. Schaible and J . Weidlein, Z . anorg. Chem., 1974, 403, 301. G. S. Koptev, N. F. Stepanov, K. N. Semenenko, and B. M. Bulychev, Vestnik Moskou. Uniu., Khim., 1974, 42. M. Hargittai, I. Hargittai, and V. P. Spiridonov, J.C.S. Chem. Comm., 1973, 750. K. Gosling and R. E. Bowen, J.C.S. Dalton, 1974, 1961.

Inorganic Chemistry of the Main -group Elements 164 A determination of the crystal structure of (Me,Tl)' [AlMe,(NCS)]shows that the Al-NCS unit is present, as opposed to the Al-SCN group found in the same anion with the cation NMe;.37q The suggested reason is that there is a significant T1- - - S interaction, which stabilizes the N-bonded form. K(Al,Me6N3) contains a bridging N, There are two forms, however, one being of CZU symmetry (Me groups in the eclipsed conformation) and one of C, (Me groups staggered). U.V. photoelectron spectra have been reported -for a number of adducts of Et,Al and EtzZn.381These show characteristic shifts in bands due to the lone-pair of electrons on the donor. Et,A1 has been confirmed as being a harder acid than Et,Zn. Triethylaluminium reacts with bis-diphenylphosphino-n-propylamineand bis-diphenylphosphino-n-butylamineto give five-co-ordinate (1: 1) adducts of Al.382No reaction occurs with more sterically hindered amines. In these, steric hindrance prevents the P lone-pair from being available to the Al. N.m.r. spectra of the adducts Et,XAl,NH,Bu' (X = C1, Br, or I) may be analysed assuming free rotation about the Al-C and N-C bonds at room temperat~re.,'~Thermal decomposition of these adducts leads to dimers containing the (AlN), ring. When X = Br, (EtBrAlNHBu'), is formed, having three isomers in solution. The most stable isomer can be crystallized out, and shown to have the structure (68).

A series of volatile, tricyclic derivatives (N,C,H,MR,),, where M = A1 or Ga; R = H , D, Me, Et, or C1. results from reactions of pyrazole with the appropriate A1 or Ga A number of physical properties are consistent with the presence of six-membered rings (4N, 2M) in the boat conformation, although inversion processes are rapid even at -90 "C. A C N D 0 / 2 calculation on the (Me2NA1H2),molecule suggests that the structural parameters obtained from electron diffraction are superior to

"' S.

K . Seale and J . L. Atwood, J. Organometallic Chem., 1974, 64, 57. J. L. Atwood and W. R . Newberry, J. Organometallic Chem., 1974, 65, 145. "' G. Levy, P. de Loth. and F. Gallais, Compt. rend., 1974, 278, C, 1405. ''' D . F. Clemens, R. B. Smith jun., and J . G. Dickinson. Canad. J. Chem., 1973, 51, 3187. 3R3 R. E. Bowen and K . Gosling, J.C.S. Dalton, 1974, 964. 3x4 A . Arduini and A. Storr, J.C.S. Dalton, 1974, 503. ""

Elements of Group 111 those from X-ray lar A-! - - -+l interactions. \\

165 Evidence has been found for strong transannu-

II

A 1' Each A1 and N is bound (MeAlNMe), possesses a novel cage to one Me and 3 cage atoms, while each (AlN), unit has approximate C3" symmetry and is well separated from others. The mean Al-N bond length is 1.96 [Cr(NH),][A1(nta),],4H20, where nta is the nitrilotriacetate anion, undergoes a solid-phase reaction to give, finally, Al[Cr(nta),]. It is suggested that the nta'- anion undergoes changes in its co-ordination type during this reaction .387 Stepwise stability constants for complex formation between All" or In''' and 2 -asparaghe or E -glutamine have been evaluated from potentiometric data.38R Al,Cl, reacts with excess PF, to give F,P-AlCl,, for which molecular weight and n.m.r. data support an ethane-like structure with an A1-P bond.," Halogen exchange occurs, to form PCl, + AlF,. Some evidence has been found for reaction in the systems Al,Me6-PF3 and -NH3, but not in Al,Me6-CO, Al,Cl,-CO, BF3-PF3, or A1,C1,-PCl3. Metallation of HPMe, with LiC,H, in diglyme, at -40°C, followed by reaction with A1C13, gives the compound LiA1(PMe2)4.390 This may be used to introduce PMe, groups into Si-X species, by replacement of X.

A.

Compounds containing A1-0, Al-S, or Al-Se Bonds.-The assignment of a band at 503 cm-I to the bending mode of A1,O (D. M. Makowiecki, D. A. Lynch, and K. D. Carlson, J . Phys. Chem., 1971, 75, 1963) has been d i s p ~ t e d . ~A " suggested reassignment of this feature, to the €3," mode of rhombic A1202,has been made. Further work on matrix-isolated i.r. spectra of A1,O has revealed that the bands previously assigned as v1 for this species (ca. 700cm-I) are in fact also due to a dimeric The molecular parameters of M,O (M = Al, Ga, In, or TI), determined by electron diffraction, are listed in Table 4.393A group of Russian workers reported similar data, independently, for Al,0.794 MO calculations, both

"'

M. Pelissier. J.-F. Labarre. L. V. Vilkov, A. V. Golubinsky, and V. S. Mastryukov, J. Chim. phys., 1974, 71, 702. P. B. Hitchcock. G . M. McLaughlin. J . D. Smith, and K . M. Thomas, J.C.S. Chem. Comm., 1973, 934. '" R . Tsuchiya, A. Uehara. and E. Kyuno. Chem. Letters, 1974, 595. ''' R. C . Tewari and M. N. Srivastava, Indian .I.Chem., 1973, 11, 700. 38L) E. R . Alton, R. G. Montemayor, and R . W . Parry, Inorg. Chem., 1974, 13, 2267. 390 G.Fritz and H. Schafer, Z . anorg. Chem.. 1974, 406, 167. 3y1 C.P. Marino a n d D. White, J. Phys. Chem., 1973, 77, 2929. 392 D. A. Lynch jun., M. J. Zehl, a n d K . D. Carlson, J. Phys. Chem., 1974, 78, 236. w3 S. M. Tolmachev and N. G. Rambidi. High Temp. Sci., 1973, 5 , 385. 3v4 S. M. Tolmachev, Yu. S. Ezhov, V. P. Spiridonov, and N. G. Rambidi, J. Struct. Chem., 1973, 14, 854.

Inorganic Chemistry of the Main-group Elements

166

Table 4 Molecular parameters of M,O (M = Al, Ga, In, or T1) Oxide A120 Ga,O

ln,O T1,O

~(M-o)/A 1.72*0.01 1.82 0.0 1 2.00*0.01 2.15*0.01

*

LOMOP 144.5*5 140.5 f 5 144*5 133+5

T/ K 2300-2300 1300 1300 900-1000

CNDO and ab initio, give results which are not consistent with these data.," The homogeneous gas-phase reaction between A1 and 0, proceeds via the rate-determining step: A l + 0, -+ A10+ 0 with a rate coefficient of (3 f2) x lo-" ml molecule-' s-l. This appeared to have no measurable temperature dependence over the range 10001700 K.3y6 Equilibrium measurements in flames give a value for the dissociation energy of A10 of 5.06 f0.08 eV, in agreement with mass-spectrometric results.3y7 Multi-configuration SCF wavefunctions for the ground and some lowIying excited states of A10 reproduce the measured geometrical parameters for this molecule quite well.3y8 1.r. and Raman spectra of KMO,,1.5H2O (M = A1 or Ga) have been interpreted in terms of the presence of [M,0(OH),]2- ions.3yyThese are formed from two MO, tetrahedra sharing one 0 atom. Assignments have been proposed for most of the fundamentals. New oxime derivatives of Al, e.g. Al(OPr'),-,(ONCR'R2),, where R' = H, Me, Et etc., R Z = M e , Et, or Pr", and n = 1-3, result when aluminium tri-isopropoxide reacts with aldoximes and k e t o x i m e ~ . ~ ~ ~ Schiff-bases containing a functional OH group ortho to the azomethine group (CH=N) react with aluminium tri-isopropoxide to give a number of Al-Schiff -base derivatives, Al(OPr'), .,,(SB),,, with n = 1-3.401 'H, I3C, and "A1 FT n.m.r. spectra of tetrameric aluminium isopropoxide are consistent with the structure (69; R = CHMe,).'" One M-C bond in MR, ( M = A l , Ga, In, or T1; R = M e or Et) can be cleaved by SO, in a 1 : l molar reaction.403 The resultant dialkylmetal alkylenesulphonates are dimeric or trimeric in benzene solution, with M atoms bridged by R(O=)SO, groups. The In and T1 compounds are soluble in H 2 0 , dissociating to R,M' and RSO;. E. L. Wagner. Theor. Chirn. Acta. 1974, 32, 295. A. Fontijn, W. Felder, and J . J . Houghton, Chern. Phys. Letters, 1971, 27, 365. "" P. Frank and L. Krauss, Z. Naturforsch.. 1974. 29a, 742. 3y8 G . Das, T . Janis, and A . C. Wahl, J. Chern. Phys., 1974, 61, 1274. 3yy J . Haladjian and J . Roziere, J. Inorg. Nuclear Chern., 1973, 35, 3821. 40n A. Singh, A . K. Rai, and R. C. Mehrotra. Indian J. Chern., 1973, 11, 478. 4U I R . N. Prasad and J. P. Tandon, J. Inorg. Nuclear Chern.. 3974, 36, 1473. J . W. Akitt and R . H. Duncan, J. Magn. Resonance, 1974, 15, 162. '"'H . Olapinski, J . Weidlein. and H . - D . Hausen. J. Organornetak Chern., 1974, 64, 193. -W 3Yh

167

Elements of Group 111 ,.OR

R-AI':-

-OR

A trans -configuration has been tentatively suggested for the complex Al(nap),, where nap = 2-nitroacetophenonato or PhCOCH,NO,. This ligand chelates via the 0 atoms of the CO and NO, group^.'^' Some assignments of i.r. bands have been made. Partial hydrolysis of Me,AlCl,Et,O and Me,AlCl,NCCH,Ph complexes produces derivatives of bis(chloromethyl)alumoxane.405The spectroscopic properties of these suggest the structure (70). Me I

Et 20-

'

A1

c1

M ' e

A series of new dialkylmetal phosphoric and phosphinic acids have been prepared, i.e. of Al, Ga, In, and Tl.'06 Bis(dimethyla1uminium) sulphate has been prepared by the action of Na2S04 on the corresponding chloride or bromide. In solution it is while in the solid phase it is polymeric.'"' monomeric, DZd, Little work has been done on the Group 111 hydrogen sulphates. Vandorpe and Drache, however, have prepared the compounds M(HSOJ, (M = A1 or Ga) by the reactions: M(SO,Cl), + 3H,O

+ M(HSO,),

+ 3HC1

At low H,O pressures the anhydrous compounds are formed; excess H,O produces the hexahydrate~.~'~ 4"4

405

4"6 407

408

R. Astolfi, I . Collamati. and C. Ercolani, J.C.S. Dalton, 1973, 2238. M. Boleslawski, S. Pasynkiewicz, A . Minorska, and W. Hrynibw, J . Organometallic Chem., 1974, 65, 165. B . Schaible, W. Haubold, and J . Weidlein. Z . anorg. Chem., 1974, 403, 289. H. Olapinski and J. Weidlein, Z.Naturforsch., 1974, 29b, 114. B. Vandorpe and M. Drache, Compt. rend., 1973, 277, C , 1121.

168

Inorganic Chemistry of the Main -group Elements The triple sulphates NaMgM"'(S04)3, where M"' = Al, Ga, or In, have been prepared by thermal syntheses, and crystallographic cell parameters reported for all of them.40y "Al n.m.r. spectra of nitromethane solutions of AI(C1O4), together with trimethyl phosphate, dimethyl methylphosphonate, or dimethyl phosphite show that A13+is octahedrally co-ordinated, whereas a tetrahedral species is indicated in the presence of hexamethylpho~phoramide.~~~~ n.m.r. data were also reported for these Aluminium perchlorate and hydroxoperchlorate are both extractable from aqueous solutions by tributyl phosphate-the latter as highly polymerized species.412 If a solution of A1 phosphate is dehydrated to give a mixture with a P,O,/Al,O, ratio of 3:7, and this is then heated to 450-500 "C, a crystalline form of Al(PO,), is This is free from oligophosphate impurities. The arsenates Na,AlH,-,(As04),,yH,0 (0.6 < x < 2; 1< y < 1.5) crystallize in monoclinic lattices (space group C2/rn, C2, or C,) when x is equal to or slightly greater than 1, but in rhombohedra1 lattices when x has any other value.414The diarsenate NaA1As20, crystallizes in the monoclinic system, with the probable space group P2,lc. Molar conductances and i.r. spectral data suggest that the hydrated 6-molybdeno-alurninates and -gallates have the formulae M,[E(HMOO~)~],~H,O."" A more accurate re-determination of the crystal structure of A1,(W04), has been made.416The crystals belong to the (orthorhombic) space group Pbca; the A1 is octahedrally co-ordinated, and the A1-0 distances are between 1.86 and 1.91 A. New diffraction data for gibbsite, a form of Al(OH), with a sheet structure, confirm the 1934 The compound contains double layers of OH- ions, with A13+ ions occupying f of the octahedral sites between the layers. The present publication gives revised interatomic distances as well as the H positions. Potential-pH-temperature relationships in the A1-H20 system have been calculated by a number of methods to assess the problems associated with the corrosion of aluminium.418 R. Perret, R. Masse, J.-P. Peter, and A . Thrierr-Sorel, Cornpt. rend., 1974. 278, C , 95 1 . J.-J. Delpuech, M. R. Khaddar, A. Peguy, and P. Rubini, J.C.S. Chern. Comrn., 1974, 153. D. Canet, J.-J. Delpuech, M . R. Khaddar, and P. Rubini, J. M a p . Resonance, 1974, 15, 325. 4 1 2 1. M. Gavrilova, V. M. Klyuchnikov, L. M. Zaitsev, and I. A . Apraksin. Russ. J . rnorg. Chern.. 1973, 18, 865. 4 1 3 M.I. Kuz'nienkov, V. V. Pechkovskii, and I. 7'. Rurya, Russ. J . Inorg. Chern., 1973, 18, 517. 414 F. D'Yvoire and M. Screpel, Bull. SOC. chim. France, 1974, 121 1 . L. A. Filatenko, B. N. Ivanov-Emin, S. Ol'gin-Kin'ones. B. Zaitsev, V. I. Ivlieva, and A . I . Ezhov, Russ. J . Inorg. Chem., 1973, 18, 419. 4'h J. J . De Roer, Acta Cryst., 1973, B30, 1878. 4 L 7 H. L. Saalfeld and M . Wedde. 2.Krist., 1974, 139, 129. 4 1 x R. T. Lowson. Austral. J. Chem., 1974, 27, 105. 4oy

""

411

Elements of Group I11

169

Aluminium hydrous oxide sols consisting of spherical particles of narrow size distribution are prepared by ageing aluminium salt solutions containing complexing anions (e.g. sulphate) at 98°C for many Once the particles are formed, the sulphate ions are removed by exchange with OHfrom an added base. Solubility products of Al(OH), in aqueous solutions containing N&+, Li', Na', K', or Ca2+ions are (pK,,) 30.55, 33.15, 30.75, 30.36, and 31.00, respectively. The anomalous value for the Li-containing solution was attributed to a specific effect, the nature of which was not 1.r. and broad-line n.m.r. studies of the aluminium-containing species gibbsite, bayerite, and nordstrandite have been made.421The i.r. spectra, in the Al-0 stretching region, could be analysed satisfactorily by the factorgroup approach. For gibbsite, a model having H atoms between sheets of 0 atoms is consistent with the i.r. and n.m.r. data, but similar conclusions could not safely be made for the other compounds. The hydrothermal hydrolysis of Al" in aqueous KC1 solutions may be rationalized in terms of the equations: 2Al" and

+ 2H,O

14A13++34H,O

--i,

[Al,(OH),]"+ + 2H+

+ [Al14(OH)34]8++ 34H'

The [A114(OH)34]8+ species then yields, by an irreversible process, a precipitate of boehmite, y-A100H.422 Standard enthalpies of formation have been calculated for crystalline Cs[Al(NO,),] and Cs2[Al(N03),].423 Raman spectra have been recorded for the liquid systems A1(N03)3,nH20 (n = 20 or 9).'" In each case the spectra are consistent with the presence of [Al(OH,),]" and NO; in the form of solvent-separated ion-pairs. Bands ca. 500 and 300cm-' were assigned to ul(Alg) and u3 or U 4 ( T l g ) A1-0 stretches of [A1(H20)6]3+. The thermal decomposition of A1(N03),,9H,0 proceeds in the following sequence: 136 "C -+ Al2O3,N2O5,4.5Hz0,185 "C + hydrated A1,03.425Similar data were reported for A1,O3,1.5N,O5,8H,O. By i.r. spectroscopy, the NO; ions are not co-ordinated to A13+in any of these compounds. Basic benzoates M(OH)(C,H,O,),,~H,O (M = Al, Ga, or In) have been prepared by potentiometric tit ration^.^'^ Thermal properties and i.r. spectra were studied. A1,03 of high purity is given by the thermal decomposition of the A1 benzoate. 419

R. Brace and E. Matijevik, J. Inorg. Nuclear Chem., 1973, 35, 369 1. Chen, Canad. J. Chem., 1973, 51, 3528. M.-C. Stegmann, D. Vivien, and C. Mazikres, J. Chim.phys., 1974, 71, 761. D.Vivien, M.-C. Stegmann, and C. Mazikres, J. Chim. pltys., 1973, 70, 1502. D. D. Macdonald, P. Butler, and D. Owen, J. Phys. Chem., 1973, 77, 2474. N. V. Krivtsov, G. N. Shirokova, and V. Ya. Rosolovskii, Russ. J. Inorg. Chem., 1973, 18, so3. D. J. Gardiner, R. E. Hester, and E. Mayer, J. Mol. Structure, 1974, 22, 327. B. N. Ivanov-Emin, V. M. Kampos, B. E. Zaitsev, and A. I. Ezhov, Russ. J. Inorg. Chem., 1973, 18, 1564.

"'D. T. Y. 421 422

423 424

425 426

170 Inorganic Chemistry of the Main - group Elements A study of the temperature dependence of volatilization from the faces of leucosapphire, cx-Al,O,, leads to a value of 210 k 2 0 kcal mol-' for the energy of volatilization of this specie^."^' A study has been made of the effect of alkali contamination on Al,O,S i 0 2 catalysts (variable A1,O :SiO, ratio) in the dehydration of isopropyl alcohol and the cracking of ~ u m e n e . ~The ' ~ catalytic effect is markedly decreased by such contamination-the latter reaction being the more susceptible to this. A number of studies of phase relationships in Al-0-containing systems have been made.""'-""' Some soluble aluminosilicates (probably structural units participating in the crystallization of zeolites) have been detected in dilute solutions containing silicate and aluminate anion^.^"' Interaction of Li,CO, and the mineral eucryptite gives a trilithium aluminosilicate, 3Li,0,A1,0,,2Si0,.4"9 The rate of formation of the spinel CuAI,O, (from CuO+A1,0, in a solid-phase reaction at 950-1000 "C) can be explained adequately assuming a three-dimensional diffusion mechani~rn.~'" Cr3' ions may be replaced by A13+in FeCr,O, at 700°C; crystallographic studies confirm that all of the AP' ions are in octahedral ~ i t e s . " ~ ' Solid-phase "A1 n.m.r. spectra have been obtained for epidote, Ca,AI,(Fe,Al)Si,0,,(OH).452 Two different nuclear electric quadrupole tensors 427

V. A . Smirnov. L. V. Povolotskaya. and G . A. Mishchenuk, Russ. J. Inorg. Chem.. 1973. 18, 468.

428

E. M. Akulenok, Yu. K. Danilenko, V. V. Panteleev, E. A. Fedorov, and V. Ya. KhaimovMal'kov, Soviet Phys. Cryst., 1974, 18, 654. H . Bremer, K.-H. Steinberg, and T.-K. Chuong, Z. anorg. C'hem., 1973, 403, 72. 430 M. M. Kazakov, F. L. Glekel', and N. A. Parpiev, Russ. J. Inorg. Chem., 1973, 18, 788. 4 3 ' A . A . Maksimenko and V. G . Shcvchuk, Russ. J. Inorg. Chem., 1973, 18, 741. 4-32 S. I . Berul' and N. I. Griskina, RUSS.J. Inorg. Chem., 1973, 18, 1334. 433 M. Screpel, F. D'Yvoire, and H. Guerin, Bull. Soc. chim. I h n c e , 1974, 1207. 4 3 4 M. 1. Baneeva and N. A. Bendeliani, Doktady Chem.. 1973. 212, 724. 4 3 5 F. Farkas, F. Kovacs, 0. Mug, and M. Gombos, Magyar K i m . Folybirat, 1974. 80, 1. P. Fellner and K. MatiaSovsk9, Chem. Zuesti, 1973, 27, 737. 4 3 7 E. Schultze-Rhonhof, Z. anorg. Chem., 1974, 408, 21. 43H P. Macchioni and H. Saucier, Compt. rend., 1974, 279, B, 99. 439 R . H . Nafziger, High Temp. Sci., 1974, 5, 414. 44" T. N. Nadezhina, V. A . Kuznetsov. E. A. Pohedimskaya, and N . V. Belov, Soviet Phys. Cryst., 1974, 19, 266. 44 I L. M. Bogacheva, Kh. R. Ismatov, and R . Z. Karimov. Russ. J. Inorg. Chem.. 1973. 18, 1642. 142 B. G . Golovkin and A. A. Fotiev, Russ. J. Inorg. Chem., 1973. 18, 1367. 4 4 3 B. M. Nikitin and N . V. Pyatnitsa, Russ. J. Inorg. Chem., 1973, 18, 1028. 4 4 4 M. V. Mokhosoev. S. A . Pavlova. E. I. Get'man, and N. G. Kisel', Russ. J. Inorg. Chem.. 1973. 18, 1123. I "Y. Cudennec and A. Bonnin, J. Inorg. Nuclear Chem., 1974, 36, 273. 446 A . Bon, C. Gleitzer, A . Courtois, and .I.Protas, Compt. rend., 1974, 278, C, 785. "' H. Furuhashi, M. Inagaki, and S. Naka, J. Inorg. Nuclear Chem., 1973, 35, 3707. a 4 x J.-L. Guth. Ph. Caullet, and R. Wey, Bull. Soc. chim. France. IY7.1. 1758. 4 4 y Z. S. Tkacheva a n d L. K. Yakovlev, R i m . J. Inorg. C'hem.. 1073. 18, 358. H. Paulsson a n d E. Koskn, Z. anorg. Chem., 1973, 401, 172. "" F. Chassagneux and A. Rousset, Compt. rend., 1973, 277, C, 1125. 45* T. Tsang and S . Ghose. .J. Chem. Phys.. 1974. 61, 413. 429

Elements of Group I11

171 were observed, corresponding to the All and Al, sites of the epidote structure. The crystal structure of leifite, N~[Si,,Al,(BeOH),0,,],5Hz0, shows that the framework is built up almost exclusively of tetrahedral anions, linked three-dimensionally, except for the Be tetrahedra.453 Diffuse X-ray scattering measurements on a non-stoicheiometric spinel, Mg0,3A1,03, having 10% of octahedral vacancies, lead to the conclusion that the probability of a vacancy occupying a site adjacent to another vacancy (Pw) is 0.20 (cf. 0.10 for a completely disordered The structure of brazilianite, NaA13(P04)2(0H)4, is made up of chains of edge-sharing A1-0 octahedra linked by P-0 tetrahedra, with Na situated in cavities in the The 2p ionization energies of Al in an aluminosilicate containing 6 C.N. aluminium only (kyanite), and in one containing both 4 and 6 C.N. aluminium (e. g. sillimanite) are almost identical.456Thus in such minerals the A1 2p ionization energies cannot be used to diagnose the C.N. of the Al. Reactions of aqueous alkaline media (containing TI', Ba2++ Tl', Ba2' + Li', or Ba2++ Na') with metakaolinite and kaolinite (for Ba2++Li+ only) Non-zeolites included a barium silicate yield a wide variety of hydrate, barium aluminate, aod a number of unidentified "1-containing species. Zeolites of the following types were grown: (i) edingtonite-type (Ba/Li, Ba/Tl) (ii) variants of zeolite L (Ba/Tl, Ba/Li, Ba/Na) (iii) harmotome- or phillipsite-types (Ba/Li, Ba/Na) (iv) gismondite-type (Ba/Na) (v) gmelinite-type (Ba/Na) (vi) yugawaralite-type (Ba/Li) (vii) a lithium-bearing zeolite having no natural counterpart (Ba/Li). The occupancy factor of A1 and Si atoms in a 53% dealuminated Y zeolite, and in the non-dealuminated sample, is ca. 1 in each case.458Thus A1 extraction does not lead to holes in the structure. The synthetic zeolite (Na, Me4N)-V, which is closely related to zeolite N, zeolite 2-21, and zeolite (Na, Me4N) of unknown structure, has been characterized in various ways.459

4s3 454 4s5 456

4s7 458 459

A. Coda, L. Ungaretti, and A. Della Giusta, Acta Cryst., 1974, B30, 396. G. Patrat, M. Brunel, and F. de Bergevin, Acta Cryst., 1974, A30, 47. B. M. Gatehouse and B. K. Miskin, Acta Cryst., 1974, B30, 131 1. P. R. Anderson and W. E. Swartz jun., Inorg. Chem., 1974, 13, 2293.

R. M. Barrer, R. Beaumont, and C. Colella, J.C.S. Dalton, 1974, 934. P. Gallezot, R. Beaumont, and D. Barthorneuf, J. Phys. Chern., 1974, 78, 1550, R. M. Barrer and R. Beaumont, J.C.S. Dalton, 1974. 405.

172 Inorganic Chemistry of the Main - group Elements Several studies have been made of i.r. and crystal struct u r e ~ of~ various ~ ~ - ~ zeolites. ~ ~ (Me,A1)2S is prepared by the reaction of AlMe, with liquid H,S.467It dissolves in benzonitrile with the formation of a 1: 1 complex. The crystal structure of a new high-pressure phase AgAlS2-I1 has been determined.46RIts space group is P3mI (trigonal), and the structure comprises an h.c.p. arrangement of S atoms, with A1 in the octahedral and Ag in the tetrahedral sites. A study of the Al-Al,S, phase diagram reveals the existence of a sub-sulphide, AlS, which seems to be stable only within the temperature range 1010-1060 "C.*"" New cubic high-pressure phases of A1&, Al,Se,, and CuInAi,Se, have been reported; all have spinel-like s t r ~ c t u r e s . ~ ~ ~ ~ ~ ~ ~ Aluminium Halides.-Matrix-isolation techniques have allowed isolation of AlF3, AlF, (AIF),, GaF,, and GaF, which have been examined by i.r. spectroscopy in the range 33-4000 cm-1.472The methods used for generating the species were as follows: (a) Knudsen-cell effusion from GaF,, GaF,+Ga, or GaF,+Al; ( b ) codeposition of Ga or GaF and molecular F, or F atoms. Cryoscopic measurements on the NaF-rich side of the system NaF-AlF3Na20-A1,03 suggest that the chief Al/O-containing species is an A120F:-x complex (containing an Al-0-A1 The only bands seen in the Raman spectrum of the LiF-Li,A1F6 eutectic were assignable to AlF:-; no evidence was found for AlF;, AlF,, or any other species derived from the dissociation of AlF2-.474 Values for the enthalpies of fusion of alkali-metal cryolites may be obtained, using an aneroid, inverse-drop calorimeter with adiabatic shields .475 Some reports of phase relationships in [A1F,I3--containing systems are given in refs. 476-478. 460

L. M. Vishnevskaya. A. A . Kubasoc.. K. S. Tkoang. and K. V. Topchieva, Russ. J. Phys. Chem.. 1973, 47, 873. K.-H. Steinberg, H . Bremer, F. Hofmann, C. M. Minachev. R. V. Dmitriev, and A . N . Detjvic, Z. anorg. Chem., 1974, 404, 129. 142. 462 K.-H. Steinberg, H . Bremer, and F. Hofmann, Z. unorg. Chem., 1974, 407, 162. 463 K.-H. Steinberg, H. Bremer, and F. Hofmann, Z. anorg. Chem., 1974, 407, 173. 464 E. G h i . Cryst. Struct. Comm., 1974. 3, 339. 4h5 P. E. Riley and K. Seff, Inorg. Chem., 1974. 13, 1355. 4hh A. A. Kubasov, K. U . Topchieva, and A . N . Ratov, Russ. J. Phys. Chem.. 1973. 47, 1023. 467 M. Boles,hwski, S. Pasynkiewicz, A. Kunicki. and J . Smola.. .J. Orguncmetalfic Chem.. 1974, 65, I h l . 468 K.-J. Range. G. Engert, and A . Weisx, Z. Nuturforsch., 1974, 29b, 186. 469 T. Farland, J. Gornez, S. K. Ratkje, a n d T. gstvold, Acta Chem. Scand. (A), 1974, 28, 226. 470 K.-J. Range a n d H . 4 . Hubner, Z. Nu!urforsch., 1973, 28b, 353. 47 1 K.-J. Range and H.-J. Hubncr, Z. Naturforsch., 1973. 28b, 3 5 5 . J72 J . W . Hastie, R. H. Hauge. and J . I-. Margrave, J . Fluorine Chem., 1973, 3, 285. 4 7 3 T. Fprland and S. K. Ratkje, Acta Chem. Scand., 1973, 27, 1883. 4 7 4 S . K. Ratkje and E. Rytter, J . Phys. Chem.. 1974, 78, 1499. "' B. J. Holm and F. Granwold. Acta Chem. Scand., 1Y73, 27, 2043.

173 Elements of Group I11 The enthalpy of mixing of molten NaF and AIF, may be measured directly by isothermal calorimetry at 1284 K, in the composition range 0-25'/0 AlF,, and by drop calorimetry in the range 25--50% A1F3.479 There is no evidence, again, for any anion other than AlF;-, although there is some dissociation to AlF, and F-. Solutions of hexafluoroaluminic acid can be prepared by dissolving ALO, in aqueous HF."" On addition of the appropriate cation, salts of the AlF$ ion are precipitated. Concentrated solutions of the acid are only stable for short times, and give P-MF,,3Hzo on standing. 1.r. and Raman spectra of K3MF, (M=Al, Ga, In, or TI) have been obtained and v l ,v3, v4, and v 5 assigned for each of the octahedral anions.481 A refinement of the structure of prosopite, an aluminofluoride mineral, CaAl,F,(OH),, has been reported.4*' X-Ray data were also given for tikhonenkovite, Sr,[Al,F,( OH),],2 H,O .483 KAlOCl, has a structure derived from cubic close packing of C1 atoms, with all the octahedral sites populated statistically by the cations, (K+ A,).'" The tetrahedral sites are half-populated by oxygens. The Li+ and Na' salts are isostructural, but contain vacancies. A study of 13C n.m.r. spectra of solutions of AlCl, in EtOH, in the presence of C10; ions, has established that the anions participate in co-ordination to the A13+ion, in addition to the solvent. Contact ion-pairs or triplets, such as A1Cl2+,AlCld, and A1(C104)2+,were suggested as the most likely species.485 Photoelectron spectroscopy in the range 50--250°C has been used to study the equilibria: 2MX3 MZX6 (M = Al or Ga; X = Cl,,Br, or I). The p.e. spectra of the monomers are all very similar to those of BX,, while the dimer within any series is favoured by the lightest M or X.4x6 1.r. spectra of monomeric MX, (M= Al, Ga, or In; X = C1, Br, or I) have ~ 'and v4 were found to have been measured in the range 30-700 ~ r n - ' . ~v2 very similar values in each case. Highly reactive A1 powder is prepared by reducing anhydrous aluminium halides in organic solvents (e.g. THF) under an inert "' S. A. Mikhaiel, Acly Chem. Srand, 1973, 27, 397Y. 477

J. Vrbenskri, I. KoStenskit, and M. Malinovsk?, Chem. Zuesti, 1973, 27, 577. Fellner, Coll. Czech. Chem. Comm., 1973, 38, 3014. 47y J . L. Holm, High Temp. Sci., 1974, 6, 16. '"' V . kepanovit, S. RadosaljeviC, and J . MiSoviC. J. Fluorine Chern., 1973, 3, 403. 'I M . J . Reisfeld, Spectrochim. Acta., 1973, 29A, 1923. Z. V . Pudovkina, N. M. Chernitsova, and Yu. A. Pyatenko, J. Struct. Chem.. 1973, 14, 345. 4x 7 Z. V . Pudovkina, N. M. Chernitsova, and Yu. A. Pyatenko, J. Struct. Chem., 1973, 14, 445. 4x4 V . G. Kuznetsov, S. I. Maksimova, and A. I.. Morozov, J. Struct. Chem., 1973, 14, 441. 4 x 5 J . S. Martin and G. W. Stockton, J . M a p . Resonance. 1973, 12, 218. 4R6 M. F. Lappert. J. B. Pedley, C. J . Sharp, and N . P. C . Westwood, J. Electron Spectroscopy, 1974, 3, 237. 4H7 G. K. Selivanov and A. A. Mal'tsev, J . Struct. Chem., 1.973, 14, 889. "' R . D. Rieke and L.-C. Chao, Synth. React. Inorg. Metal-org, Chem., 1974, 4, 101.

"' P.

174

Inorgqnic Chemistry of the Main-group Elements The ClAlCl bond angle in AlCl,-NH, is l16.9*0.4°.4s9 This contradicts an earlier value for the angle in AlCl, itself of ca. 112" (M. L. Lesiecki and J. S. Stirk, J . Chem. Phy., 1972, 56, 4171). A tensimetric analysis of the vapours above MAlCl, (M = alkali metal) shows that they contain AlCI, and MAlCl,.""' The partial pressure of the former decreases along the series from Li to Cs. E.m.f. measurements using the cell: Al(s)~AICl,-MC1(~)(C12 (graphite) yield (M=Na, K, Rb, or Cs), in the temperature range 200-600°C, thermodynamic data which, in the concentration range around 50 mol% of A1C13, may be interpreted in terms of the eq~ilibria:~" Al,Cl, A1,Cl;

+ Ci- * A1,Cl;

+ C1- * 2AlC1;

At 600K, Al,Cl,(g) reacts with CrC1, to give a gaseous complex CrAl,Cl,.""' The electronic spectrum of this leads to the suggestion that the Cr has distorted octahedral co-ordination (by Cl's). Pd(AlCl,), may be prepared by an analogous reaction.493 The X-ray powder diffraction pattern could not be indexed unambiguously, while a small paramagnetic susceptibility was found, indicative of distortion from square-planar geometry. "Cl n.q.r. spectra have been reported for the chloroaluminate groups in Te,(AlC1,)2, Bi5(AlC14)3,e t ~ . , ' Those ~ with ionic AlCl; units give chlorine transitions in the range 10.6-11.3 MHz, while those in which the AlCl; groups are more strongly co-ordinated, or form Al,Cl;, give such transitions at higher frequencies. A number of new complex Al-containing halides have been detected mass-spectrometrically, e. g. CuAlCl, and CU,A~,C~,."~' Phase-relationships in the systems A1C1,-MgC1,-Et20496 and 6Na, 3Ba,2A1, 6C1497have been elucidated. There is some evidence for the interaction of alkynes with AlBr, at low temperature^.^^' Thus, pent-2-yne, hex-2-yne, and hex-3-yne all give i.r. bands ca. 2200 cm-' assigned to (alkyne)AlBr, complexes. 4xy 4y"

")' 4y2 4Y1

494

495 496

"' "'

I. Hal-gittai and M. Hargittai, J . Chem. Phys.. 1971. 60, 1563. A. I . Morozov and I. S. Morozov, Russ. J. Enorg. Chem., 1973, 18, 520. H . Ikeuchi and C. Krohn. Acta Chem. Scand., 1974, 28A, 38. M. Aits and H. Schafer, Z . anorg. Chem., 1974. 408, 37. G . N. Papatheodorou, Inorg. Nuclear Chem. Letters. 1974, 10, 115. D. J. Merryman. P. A. Edwards, J . D. Corbett, and R. E. McCarley, Inorg. Chem., 1974, 13, 1471. M. Binnewies and H . Schafer, Z . anorg. Chem., 1974, 407, 327. K. M. Sernenenko, E. A. Lavut, and A. P. Isaeva, Russ. J. Inorg. Chem., 1973, 18, 433. M. A. Kuvakin, L. I. Talanova, and A. I. Kulikova, Russ. J. Inorg. Chem., 1973, 18, 602. H. H. Perkampus and W . Weiss. Z . Naturforsch.. 1974, 29b, 61.

Elements of Group I11

175

TeC14 forms stable, highly polar, 1:1 complexes with A1Br3, GaCl,, and GaBr3.499 Hydrolysis of NaAlBr, proceeds by different mechanisms, depending on the temperature.500The first stage in the low-temperature mechanism is the formation of a hexahydrate, which has been characterized by X-ray powder diffraction. 3 Gallium General.-Gallium complexes of rn -cresolphthalexon S (a compIexone derived from the triphenylmethane fragment, containing 0 and N donor atoms) have some potential for the photometric determination of Ga.501 Ga forms a mixed-ligand complex with quercetin and antipyrine in the presence of strong acids; the complex is extracted quantitatively into CHC1,.502 A rapid and simple separation method for G a and Zn involves extraction of GaI'I from aqueous acidic solutions by l-phenyl-2-methyl-3-hydroxy-4pyridone.

Gallium Hydrides.-CsGaH, forms two solvates with diglyme: CsGaH4,4DG and CsGaH4,2DG.'04 The N-methyldiethanolaminogallane dimer, [MeN(CH,CHzO)2GaH]z, contains 5 C.N. gallium-the dimerization occurring via a four-membered Ga,O, ring (71)."' The molecule has C, symmetry within experimental error.

Dideuterio(pyrazo1- 1-y1)gallane dimer has the structure shown in Figure 24.506 The six-membered ring, Ga(NN),Ga, is in the boat conformation. I. P. Gol'dshtein, E. N. Gurjianova, M. E. Peisakhova, and R. R. Shifrina, J . Gen. Chem. (U.S.S.R.),1973, 14, 2332. B. Dubois and R. Vandorpe, Compt. rend., 1973, 277, C, 1133. A. I . Busev and A. A. Cherkesov, Russ. J. Inorg. Chem., 1973, 18, 630. 502 N. L. Olenovich and L. I . Kovalchuk. Zhur. analit. Khim., 1973. 28, 2162. B. Tamhina, M. J . Herak, and K. Jakopi-it, J . Less-Common Metals, 1973, 33, 289. T. N. Dyrnova and Yu. M. Dergachev, Doklady Chem., 1973, 211, 614. '"'S. J . Rettig, A. Storr, and J. Trotter, Canad. J . Chern., 1974, 52, 2206. D. F. Rendle, A. Storr, and J. Trotter, J.C.S. Dalton, 1973, 2252.

4yy

Inorganic Chemistry of the Main- group Elements

176

Figure 24 Molecular structure of the dideuterio(pyrazo1-1 -yl)gallane dirner (Reproduced from J.C.S. Dalton, 1973, 2252) Compounds containing Ga-C Bonds.-The reaction of Ga(g) and PN(g) in the presence of solid graphite produces gallium monocyanide (detected mass-spectrometricall y) :‘07 C(s) + Ga(g) + PN(g) F iP, + GaCN(g) K+[Me2Ga(CN)2]-is prepared by the reaction : K,[Hg(CN),]

+ 2GaMe, + 2K[GaMe,(CN),] + HgMe,

An i.r. spectrum of the product, with some assignments, has been given.5o8 An electron-diffraction study of GaMe, gave the following structural pararneter~:’~~ r(GaC) 1.967 f0.002, r(CH) 1.082 f0.003 A, LGaCH 112.1*0.8”, and LCGaC 118.6”. The methyl groups are freely rotating at room temperature. Some thermochemical parameters have been listed for Ga trialkyls.“’ The trialkylgallium-halogeno complexes (R,GaX)- (R = Me or Et, X = F; or R = M e , X = B r ) and [(R,Ga),X]- (R and X as before) have been prepared, ‘and their vibrational spectra reported.’ll Compounds containing Ga-N, Ga-P, or Ga-As Bonds.-GaGaN contains layers of Ga atoms strongly bound to N atoms (Ga-N distance= 1.863 A), with Ca atoms placed between these layers (each co-ordinated to five N’S).”~ Raman spectra of a single crystal and i.r. spectra of polycrystalline NaGa(NH,), may be assigned in terms of Td symmetry for the [Ga(NH2)4]p ion at room temperature, and S, symmetry at 2 0 K.”3 5(IR

so9 51”

’12 ’13

M. Guido and G. Gigli, J . Chem. Phys., 1974, 60, 721. T. Ehemann and K. Dehnicke, J. Organometallic Chem.. 1974, 64, C33. B. Beagley, D. G. Schmidling, and I. A. Steer, J. Mol. Structure, 1973, 21, 437. G . M . Kol’yakova, 1. B. Rabinovich, and E. N. Zorina, Doklady Chem., 1973, 209, 245. 1. L. Wilson and K. Dehnicke, J. Organometallic Chem., 1974, 67, 229. P. Verdier. P. L’Haridon, M. Maunaye, and R. Marchand, Acta Cryst., 1974, B30, 226. G. Lucazeau, A. Novak, P. Molinie, and J. Rouxel. J. Mol. Structure. 1974, 20, 303.

Elements of Group III

177

1.r. data for the compounds (Me4N),[Ga(NCO),] and Ga(NC0),,3L (L= bipy or phen) indicate that the [Ga(NC0)J3- anion contains cyanate groups bonded via the 0 atom.514In agreement with this, the ionic species is unstable, decomposing in air. The other compounds contain Ga-NCO units. The standard enthalpy and entropy of formation of GaP were derived from composition and vapour-pressure measurements along the Ga-rich liquidus of the Ga-P Variable-temperature n.m.r. measurements on GaMe,-AsEt, and GaClMe,-AsEt, systems yield estimates for the free energy of formation of the adducts: Me,Ga,AsEt, 7.3 f 1.5, ClMe,Ga,AsEt, 9.7+ 1.5 kcal m 0 1 - l . ~ ~ ~ Compounds containing Ga-0 or Ga-S Bonds.-When the vapour above G a z 0 3or In,O, is condensed in low-temperature matrices, the oxides M,O and M40, (M = Ga or In) are produced, and identified by i.r. spectroscopy.517Passing 0, over In-Ga alloys yields InOGa and Ga,In,-,O,. A study of the kinetics of the extraction of Ga” from 0.1 moll-’ aqueous C10; solutions into CHCl, using thenoyltrifluoroacetone (HA), and of the back-extraction of the tris-chelate GaA,, shows that the rate-determining step in the former process involves association of the species GaOH” with A- in the aqueous The back-reaction is thought to be the exact reverse. The competing ligand system alizarin-3-sulphonic acid-OH- has been used to determine formation constants of mononuclear hydroxo-complexes of Ga at 25 “C, and the hydrolysis constants of gallium ions at I = 0.1-1 .O.”’ The methanolysis of Ga” and In” cations in anhydrous methanol produces the complex cations [Ga, (OMe),lZ’ and [Ga,,,~(OMe)p]”m’-p’, where rn’ > rn, or for In, [In,(OMe)p]‘3m-p’species appear simultaneously with monomeric [In(OMe)T’ and [In(OMe)2]+.520 Bis(dimethylgal1ium)oxalatecontains a Ga,C20, unit that is built up from two fused five-membered rings (72).521

514

515

‘Ib

‘I7 518 519

’’O

521

A. Yu. Tsivadze, G. V. Tsintsadze, and Ts. L. Maknatadze, J. Gen. Chem. (U.S.S.R.), 1974, 44, 157.

M. Ilegems. M. B. Panish, and J. R. Arthur, J . Chem. Thermodynamics, 1974, 6, 157. B. G. Gribov, G. M. Gusakov, B. I . Kozyrkin, and E. N. Zorina, Doklady Chem., 1973, 210, 515. A. J . Hinchcliffe and J . S. Ogden, J . Phys. Chem., 1973, 77, 2537. T. Sekine, Y. Komatsu, and J.-1. Yumikura, J . Inorg. Nuclear Chem., 1973, 35, 3891. E. A . Biryuk and V . A. Nazarenko, Russ. J. Inorg. Chem., 1973, 18, 1576. L. Asso, J. Haladjian, P. Bianco, and R. Pilard, J . Less-Common Metals, 1974, 35, 107. H.-D. Hausen, K. Mertz, and J. Weidlein, J. Organometaflic Chem., 1974, 67, 7.

178

Inorganic Chemistry of the Main -group Elements

The new compounds 2GaONO3,N,O, and Cs[Ga(NO,),] have been prepared, while the species NO[In(NO,),] and Cs[In(NO,),] were synthesized by a new method.s22 The first stage in the thermolysis of Ga(SO,Cl), is dissociation into GaCI, + SO,, at 70 “C and atmospheric pressure.523The second stage involves reaction between these to give Ga,(SO,), + SO,Cl,. The GaO, octahedron in tris(acetylacetonato)gallium(m) is very close to being completely regular.524The average Ga-0 bond length is 1.952(8) A, with an average ligand ‘bite’ of 2.802A. Reactions of gallium isopropoxide with monofunctional bidentate Schiff bases, o-HOC6H4CMe=NR and 2-HOCloH&H=NR (R = Et, Pr”, or Ph), yield complexes Ga(OPr’),SB, Ca(OPr’)(SB),, and Ga(SB)352’The Ga is thought to be respectively four-, five-, and six-co-ordinate in the three classes of complex. E.s.r. parameters have been reported for the adducts Ca,Cl,-tempo and GaC1,-tempo, where tempo is 2,2,6,6-tetramethylpiperidine nitroxide.s26 Adducts of Ga and I n perchlorates with tetramethylene sulphoxide, M(C104),,6TMS0, and of Ga perchlorate with thioxan oxide, Ga(C104),,6TS0, have been prepared and ~haracterized.~’~ A considerable shift of v(S=O) to lower wavenumber indicated co-ordination via the sulphoxide oxygen. The ternary oxides CrMnGaO,, NiMnGaO,, CuMnGaO,, and ZnMnGaO, crystallize with the cubic spinel structure.”* The structure of monoclinic CaGaO, is built up from 6 G a 0 , tetrahedra, with r(Ga0) = 1.81-1.87 A.s29 Gallium metatitanate, GazTiOs, can be obtained by heating the gallium peroxotitanate [Ga(OH),], [0,Ti(OH)20],3H20,but the product is metastable, and further heating at 1000 “C leads to decomposition to Ga,O, and a gallium titanate richer in Ti.53” NaGa,,O,,(OH),, prepared by hydrothermal techniques, is monoclinic, space group P21/m.531 Both GaO, octahedra and GaO, tetrahedra are present in the structure, with mean values for r(GaO),,, and r(GaO),,, of 2.00 and 1.85 A, respectively. The phase diagram of the system MnS-Ga,S, has been determined, and 7 intermediate phases have been characteri~ed.’~~ ’” ”’ 524

’” 52h 527

528 “’)

”’ ’’’ ”()

B. V. Ivanov-Emiii. Z. K. Odinct\. V. .A. HcIonoso\. and B . E . Zaitsec. R[c,\.\. ./, I t t o r g . Cheni.. 1Y73, 18, 6 2 3 . M. Drache. B. Vandorpe. and J. Heubel. Rev. Chim. rninkrale, 1973, 10, 505. K. Dymock a n d G. J . Palcnih. A c t u Crysf.. 1974. €530, 1361. R. N . Prasad and J. P. Tandon, J. Less-Common Metals. 1974, 37, 141. C . Hambly and J . B. Raynur. J.C.S. Dultoti. 1Y71. 603. C . Vicentini and W. N. De Lima. Anuis Acud. Drasil. Cienc.. 1973, 45, 719. P. D. Bhalerao, D. K. Kulkarni. and V. Ci. Kher, Prarniina, 1973, 1, 230. H. J . Deiseroth and H. Muller-Buschhaum. Z . unorg. Chem.. 1973, 402, 201. E. Perte and M. StrBjcscu. Rev. Roumaine Chirn., 1974, 19, 395. A . N. Christensen. Acta Chem. Scand., 1974, 28A, 145. M.-P. Pardo, M. Julien-Pouzol. S. Jaulmes. and J . Flahaut, Cornpt. rend., 1973, 277, C. 1021.

Elements of Group 111

179

Gallium Halides.-NH,GaF,-NH,AlF4 and y -GaF,-y -AlF, both form continuous series of solid solutions, with linear relationships between composition and lattice constants.533 The He (I) p.e. spectra of MX, ( M = G a or In, X=C1, Br, or I) have been reported and assigned.534A comparison of these results with those for BX, suggests a revision in the assignment of the outermost e’ and e” peaks for BBr, and BI,. Ga13 and InI, exhibit splitting of the band due to ionization from an e” MO (D3,,symmetry), which suggests that either the of the ion is pyramidal. neutral ground state or the first excited state (’E”) The vibrational spectra of GaX,,H20 (X = C1 or Br) can be assigned in and H,O (C2u)rather than the terms of the ‘local symmetry’ of GaX,O (GU) overall symmetry of the adducts (Cs).535 Four ‘H n.m.r. signals are seen for solutions of GaCl, in a ~ e t o n i t r i l e . ~ ~ ~ The most intense is associated with the bulk solvent, and shows two satellites arising from 13Ccoupling. The fourth varies in area with change in Gar’’ concentration and that of total chloride (LiCl added). Co-ordination numbers of the MeCN can be calculated and show that there is substantial displacement of the MeCN from the co-ordination sphere by added LiCl. Two ’lGa signals are seen, the low-field signal being the more intense and at a similar position to that of GaCl;. The high-field signal is associated with [Ga(MeCN)J3’. Co-ordination numbers can be calculated and are in good agreement with those from the ‘H data. All the results can be rationalized on the basis of: (n + 2)Ga,Cl,

+ 6MeCN + [Ga(MeCN)J3++ 3GaC1; + nGa,C16

An improved synthesis of Bu”,GaCl,-, (n = 1-3) has been rep~rted.’~’ This is a simple metathetical reaction, in a hydrocarbon solvent: GaCl, + nLiBu” + Bu”,GaCl,-,

+ nLiCl

Vibrational assignments have been made for NO’GaCl;, prepared by the reaction of NOCl+ GaC1, in a variety of solvents, or by dissolving G a metal in NOCl.”8 A comparison of the spectra of crystalline NO’GaCli with that of the A1 analogue shows that they are closely related structurally. Series of mixed-halide complexes of Ga”, i.e. Ga,X,Y,-,, where X = C1, Y = Br or I; X = Br, Y = I; n = 1-5, are present in mixtures of G a 2 x - and Y- in MeN02 Individual members cannot be isolated, but vibrational spectroscopic data could be obtained by examining solutions 533

524

’” s3h 537 538

s39

W . Stoeger. A. Rabenau, and H. M. Haendler, Z . anorg. Chem., 1974, 408, 92. J . L. Dehmer. J . Berkowitz, L. C. Cusachs, and H. S . Aldrich, J. Chem. Phys., 1974, 61, 594. J . Roziere, M.-T. Roziere-Bories, A. Manteghetti, and A. Potier, Canad. J. Chem., 1974, 52,

3273. S. F. Lincoln, Austral. J. Chem., 1972, 25, 2705. R. A. Kovar, G. Loaris, H. Derr, and J . 0. Callaway, Inorg. Chem., 1974, 13, 1476. P. Barbier, G. Mairesse, F. Wallart, and J.-P. Wignacourt, Compt. rend., 1973, 277, C, 841. K. H. Tan and M. J. Taylor, Inorg. Nuclear Chem. Letters, 1974, 10, 267:

180

Inorganic Chemistry of the Main - group Elements

over a wide range of X/Y ratios. It was possible to assign v(Ga-Ga) in all 15 of these compounds. The Ga complex chlorobis(8-hydroxy-2-methylquinolinato)gallium(111) contains five-co-ordinate Ga (trigonal bipyramidal), with r(GaC1) = 2.190(2) A, r(GaN) = 2.108(5) and 2.104(5) If appropriate amounts of GaBr, and Ga are melted together at 180 "C for The Raman spectrum of 48 h, a species GaBr,., is deposited on this showed bands characteristic of Ga,Br;-, and so it was formulated as Gaz+Ga,Bri-, i.e. Ga4Br6. The presence of a Ga-Ga bond in Ga:'BrE- has been confirmed by an X-ray diffraction study of (Pf,N)2Ga2Br6.542 The Ga-Ga bond length is 2.419A7 and the anion possesses D,, symmetry (73). Br

\114.1" n

2.37wBr

Other Gallium Compounds.-Thermodynamic parameters for GaSb and GaSb, have been obtained from high-temperature mass-spectrometric measurernent~.~~, X-Ray and other studies on the solid solutions Gal-,Ge,Cr,N have elucidated the various structural changes which occur with temperature.'"" M06Ga1, is monoclinic, and belongs to a new structure type.545The chief structural units are MoGa,, polyhedra arranged at the corners of distorted cubes, and Ga layers. There are no Mo-Mo contacts, no Ga-Ga pairs, but some very short Mo-Ga distances. Cluster compounds Mn,(CO)& -MMn(CO),], have been prepared and

"')

541 542

s43 s44

54s

K. Dymock and G. J. Palenik, J.C.S. Chern. Comm.. 1973. 884. M. Williamson and 1. J . Worrall, Inorg. Nuclear Chern. Letters, 1974, 10, 747. H. J . Cumming, D. Hall, and C. E. Wright, Cryst. Struct. Cornrn., 1974, 3, 107 V. Piacente and G. Balducci, High Temp. Sci., 1974, 6, 254. N . Nardin, G. Lorthioir, and R . Fruchart, Bull. SOC.chirn. France. 1973, 2959. K. Yvon, Acta Cryst., 1974, B30, 853.

Elements of Group III

181

studied by X-ray diffraction (M = Ga or In).546.547 They are isomorphous and contain a planar M,Mn4 unit (74), in which there is a Mn-Mn bond. Another Ga-containing cluster compound is produced by the reaction: 3Na[Co(CO),] + GaBr,

i ,

GaCo,(CO),,

+ 3NaBr

1.r. and mass spectral data are consistent with the structure (75).548 X-Ray diffraction studies show that all members of the CuGal-,Fe,Sz When x = series ( 0 s x s 1.0) crystallize with the chalcopyrite 0.025 the magnetic moment for Fe approaches the spin-only value (5.92 B.M.). 4 Indium

General.-The half-life of the isotope ”lgIn has been measured as 30.0 h0.2 s-in agreement with, but more precise than, earlier values.5so A highly reactive indium powder is produced by the alkali-metal reduction of indium salts (e.g. InCl,) in hydrocarbon An extractio-photometric method for the determination of indium in Zn ores involves the formation of mixed complexes of In with antipyrine and q~ercetin.~~~ Indium may be estimated by photometric methods as the malachite green tetrachloroindate; this may be extracted from aqueous acid by benzene, CCL, etc.553 Compounds containing Bonds between In and Group VI Atoms.Evaluation of apparent molar volumes leads to the identification of the [h(&o)6]3+ cation in aqueous solutions of non-complexing mineral In aqueous HCl or HBr, mixed halogeno-aquo complex cations are produced, i.e. [In(H20),C1]*+etc. Dimethylindium carboxylates are formed from Me,In,OEt, + acid in Et,O.”’ 1.r. spectra of these compounds show that the carboxylate groups are biden tate. 1.r. spectra of the vapour over indium and thallium metaborates can be assigned to monomeric species MB02, which have a cyclic structure (76).’”

(76) H. Preut and H.-J. Haupt. Chem. Ber., 1974, 107, 2860. s47 H.-J. Haupt and F. Neumann, J. Organomrtnllic Chem., 1974, 74, 185. 548 W. Kalbfus, J. Kiefer, and K. E. Schwarzhans, Z. Naturforsch., 1973, 28b, 503. 549 M . DiGiuseppe, J. Steger, A. Wold, and E. K o s h e r , Inorg. Chem., 1974, 13, 1828. ”O 0. Scheidemann and E. Hageba, Inorg. Nuclear Chem. Letters, 1974, 10, 47. ’” L.-C. Chao and R. D. Rieke, J . Organometallic Chem., 1974, 67, C64. ’” N. L. Olenovich, L. I. Kovalchuk, and E. P. Lozitskaya, Zhur. analit. Khim., 1974, 29, 47. 553 P. P. Kish and I. I. Pogoida, Zhur. analit. Khim., 1974, 29, 52. s54 J. Celeda and D . G. Tuck, J . Inorg. Nuclear Chem., 1974, 36, 373. 5 5 5 W. Lindel and F. Huber, Z. Naturforsch., 1973, 28b, 517. ss6 A. M. Shapovalov, V. F. Shevel’kov, and A. A. Mal’tsev, J. Struct. Chem., 1973, 14, 514. 54h

182 Inorganic Chemistry of the Main -group Elements The indium and thallium sulphates M:M"'(SO,), (MI = Na, K, Rb, or Cs) have been prepared; they belong to the same rhombohedra1 crystal structures as the analogous A1 A study of the (NH4),S04-In,(SO,), system confirmed the existence of the anhydrous alum NH,In(SO,),, together with the sulphate (NH4)31n(S04)3, which exists in two (a and p ) forms. The high-temperature ( p ) form is rh~mbohedral.~'" (NH,),[I~(HMOO,)~(MOO~)],~H~~ has been isolated from a mixture of NH, paramolybdate and In(N0,)3 ~ 0 1 u t i o n s It .~~ is~thought that the In is octahedrally co-ordinated, with bidentate MOO, and unidentate HMoO, (77). OH

(77)

The reaction of InCl, with Cs6P3Ol0in aqueous solution leads to a number of phases of variable composition (indium basic and mixed tripolyphosphates) and also an indium tripolyphosphate with the composition Cs21nP,0,,,8H,0.5"o The In' halides react with refluxing acetylacetone ( = Hacac) to give a mixture of In(acac), and Ir~X,(acac).~"' The latter could not be isolated in pure form, but some crystalline derivatives could be produced by reaction with N-donors, e.g. [InX,(acac)(L-L)],EtOH (L-L = 2,2'-bipyridyl or 1 , l O phenanthroline) or [InX,(acac)L,],EtOH (L = py or ['H,]py). These are all apparently six-co-ordinate, with InO,X,N, units, but no decision could be arrived at concerning the symmetry of these. Indium(1ir) carboxylates In(RCOO), (R = H, Me, Et, P f , Pr', or But) have been prepared from metallic In or InMe, and the anhydrous carboxylic acid. The i.r. spectra show that the carboxylate groups could be either chelating or bridging, but no definite conclusion concerning the structure or the C.N. of the In could be reached.562 Stability constants have been determined for the species [In(C4O,H,),l3and [In(C406H3),]"-obtained by interaction of In3' with tartaric Solvent extraction of indium(rI1) thiocyanate, In(SCN),, with tributyl phosphate in hexane is markedly enhanced by the presence of background NaC104: it was concluded that this is due chiefly to a salting-out effect.564 517

R. Perret, J . Tudo, and B. Jolibois, J. Less-Common Metals, 1974, 37, 9. Tudo, M. Tudo, and R. Perret, Compf. rend., 1974, 278, C, 117. B. N . Ivanov-Emin, L. A. Filatenko, B. E. Zaitsev, and A . 1. Ezhov. Russ. J. Inorg. Chern., 1973, 18, 512. G. V. Rodicheva, E. N . Deichman, I. V. Tananaev, and Zh. K . Shaidarbckova, Russ. J. Inorg. Chern., 1973, 18, 1352. J . G. Contreras and D. G. Tuck, J.C.S. Dalton, 1974, 1249. W. Lindel and F. Huber, Z . anorg. Chem., 1974, 408, 167. G. Marcu, M. Suciu, and A . V. Botar, Rev. Roumaine Chim., 1974, 19, 577. Y . Hasegawa a n d T. Sekine, J. Inorg. Nuclear Chern., 1974, 36, 421.

"' J. '"' 5hL 563

564

Elements of Group 111 183 Some information on the structure of amorphous InSe and InTe films has been obtained by electron-diffraction Indium Halides.-Compositions of halogeno- and thiocyanato-complexes of In in DMSO have been determined potentiometrically at 25 "C, and stability constants have been calculated.566 The Raman spectra of molten InC1,-KCl mixtures (50-100 mole% InC1,) may be analysed in terms of the species InCl;, In2C1;, and In2C&.567 These are thought to have similar structures to the A1 and Ga analogues. Raman spectra of the indium bromides InBr,, InBr,, In,Br,, In,Br,, In,Br,, and InBr have been obtained in the solid phase. For In4Br7,InsBr7, and In7Br9 these were consistent with the formulations: 51r1+(InBr;),(InBr,)~-, 31n+(InzBr6)'-Br-, and 61n+(InBr,)3-3Br-, respect i ~ e l y . ' The ~ ~ phase In,Br, could not be confirmed; InI, gave a spectrum consistent with In+(InIJ . "'In and halogen n.q.r. spectra of several dimethylindium compounds show that Me,InBr and Me21nI have the Me,TlBr-type of structure (linear MeJn equatorially surrounded by a square-planar arrangement of halogens).569MeJnCl is distorted from this, while the MeJnF has a nonlinear MeJn group. 'MeInI,' has been confirmed as [Me,In][InI,], and MeInBr, and EtInI, are halogen-bridged dimers. The small asymmetry parameter found in the n.q.r. spectrum of MeInI, is evidence for the presence of MeJn' and InIf- ions (or possibly a polymeric unit containing axially symmetric In atoms), and not an unsymmetrical dimer.570 Phase diagrams of the systems TlI-InIS7' and M12-In12, where M=Cd, Zn, Sn", Pb", Co", or Mn1',572have been reported.

Other Indium Compounds.-The adducts CpIn,BX, (X = F, C1, Br, or I) have been prepared by the simple reaction between CpIn and BX,.573Their vibrational spectra are consistent with the presence of monomers (78).

mH

In-B-X/x

"' Yu. G. Poltavtsev, V. P. Zhakarov, and T. V. Remizovich, Soviet Phys. Cryst., 1974,18,701. V. M. Samoilenko and V. I. Lyashenko, Russ. J . lnorg. Chem., 1973, 18, 1578. H. A. @ye, E. Rytter, and P. Klaeboe, J . Inorg. Nuclear Chem., 1974, 36, 1925. 5'R J. E. D . Davies, L. G. Waterworth, and I . J. Worrall, J . Inorg. Nuclear Chem., 1974, 36, 805. "') D . B. Patterson and A. Carnevale, Inorg. Chem., 1974, 13, 1479. 570 W. A. Welsh and T . B. Brill, J . Organometallic Chem., 1974, 71, 23. 5 7 1 0. N. Postnikova, Yu. N. Denisov, P. I. Fedorov, N. S. Malova, and L. A. Radushkevich, Russ. J. Inorg. Chern., 1973, 18, 762. "* Yu. N. Denisov, N. S. Malova, and P. I . Fedorov, Russ. J. Inorg. Chem., 1973, 18, 722. 573 J. G. Contreras and D. G. Tuck, Inorg. Chem.. 1973, 12, 2596. 566

567

Inorganic Chemistry of the Main -group Elements

184

In,Te, is isomorphous with In,Se,."" The structure is built up of two centrosymmetrically related interlocking continuous sheets of atoms running perpendicular to a. These are constructed of interlinked fivemembered InTe rings forming chains parallel to c, which are cross-linked by strongly bound In-In-In units, forming, in ionic terms, the homonuclear triatomic species (In$+. C O h 3 is made from the elements at 4OO0C, and is stoicheiometric. It crystallizes in the tetragonal system, and the structure is based on layers of square-triangular nets, related to CoGa, and Si2U,.57s Lattice constants have been reported for the hexagonal phases M,In, (M = Gd, Tb, Dy, Ho, or Y: all belong to the W,Si, structure type) and Y21n (of the NiJn structure type).576 5 Thallium

Thallium(1rr) Compounds.-The electron-transfer reaction between T1' and ~ ~the Tl"' in the presence of Ce'" proceeds via T1" as an i n t e ~ m e d i a t e . 'In absence of such one-electron oxidants, two electrons are transferred from the T1' to the Tl"' in a single step. TI"' behaves as a one-electron oxidant towards oxalic acid in aqueous H 2 S 0 4in the dark.578Evidence has been presented for the presence here also of T1". Oxidation of AS'" by T1"' in HClO4 solution is inhibited by C1-, and the reactivity of the various thallium species is in the order T13+>T1C12' > TlCl: > TlC1, > TlCl;.579 Oxidation proceeds by way of an intermediate complex between Tl"' and AS'". The crystal structure of Me,TlCl reveals that it is built up essentially from discrete, linear Me,Tl' ions and Cl-.580The T1 is approximately octahedrally co-ordinated, with two C's at 2.139 A and 4 Cl's at 3.029 A. Thallium-containing adducts isolated from reactions between bridged olefins such as benzonorbornadiene or norbornene and Tl(OAc),-, (N,), have been characterized, e.g. (79; X = OAc or N3).581 A number of anionic T1"' complexes containing terdentate ligands have been prepared.'" Examples are R2TlL-, where R = Me or Ph, L = Aat or Sat [the compounds H,Aat and H,Sat being 4-(2-benzothiazolinyI)-2-pentanone and 2-(o-hydroxyphenyl)benzothiazoline, respectively]. The idealized structure of the Aat'- complex is (80).

"' J .

H. C . Hogg and H. H. Sutherland, Acta Cryst., 1973, B29, 2483.

"' H. H. Stadelmaier. J . D. Schobel, R. A . Jones. and C . A. Shumakcr. Acta Cryst.. 2926. 5 7 h E. Franceschi. J. Less-Common Metals, 1974, 37, 157. 577 G . Wada and K. Tamaki, Bull. Chem. SOC. Japan, 1974. 47, 1422. 5 7 x V. S. Srinivasan and N . Venkatasubramanian, Indian J. Chem., 1973, 11, 702. 5 7 ' ) P. D. Sharma and Y. K. Gupta, Austral. J. Chem.. 1973, 26, 21 1.5. '"' H.-D. Hausen, E. Veigel, and H.-J. Guder, Z . Naturforsch.. 1974. 29b, 269. -"' E. Maxa, G. Schulz, and E. Zbiral, Annalen, 1974, 933. "' L. Pellerito, R . Cefalu, and G . Ruisi, J. Organometallic Chern., IY73, 63, 41.

1973, R29,

185

Elements of Group 111

(79)

(80)

The vibrational spectra of the anions Me3TlCN- and (Me3Tl),F- may be The T1-F-T1 assigned in terms of C3uand D,, symmetries, re~pectively.'~~ bridge in the latter, therefore, must be linear. A number of cyclopentadienyl and indenyl derivatives of Tl"' have been rep~rted.~*~.~~~ Reduction of (C,H,)Tl"'Cl by the Na salt of naphthalene gives (C,H,),Tl,--containing one Tl"' and one T1' atom.s86 A thin film of TlN, formed from Tl+N, by reaction during cathode sputtering, has the hexagonal, wurtzite The oxide of thallium T140, may be formulated as T1:Tl'1'03.588The Tl"' atoms are situated at the centres of distorted T10, octahedra, while the T1' atoms are of 3 types, placed between parallel double lines of Tl"'0, units. In each case the T1' lone pair is stereochemically significant. Ba,Tl,O, forms orthorhombic crystals, isotypic with Ca2Fe205.589 The complexes TI[(TT-C~H~)M(CO),]~ (M = Cr or Mo) and Tl(.rr-C,H,)Cr(CO), have been prepared in quantitative yield by the reaction of [(.rr-C5H5)M(CO),],with metallic Tl.590 Thallium(1) Compounds.-T1' in the gas phase may be generated using hexafluoroacetylacetonatothallium(1)as precursor.591The T1' ion has been shown, mass spectrometrically, to form 1: 1 complexes in the gas phase with the following ligands: EPh, (E = P, As, or Bi), 1,lO-phenanthroline, 2,2'and 4,4'-bipyridyl, and phenanthrene. Some 'T1 n.m.r. spectra have been reported for T1' ions in aqueous The relaxation (longitudinal and transverse) of the T1 ions is independent of the resonance frequency, isotopic substitution of the solvent, salt concentration, or nature of the anions. It is very sensitive to 5x3

s84 s85

58h 587

*" 58y

s90

"'

s92

T. Ehemann and K. Dehnicke, J. Organometalfic Chem., 1974, 71, 191. N. Kumar, B. L. Kalsotra, and R. K. Multani, J. Inorg. Nuclear Chem., 1973, 35, 429.5. N. Kumar, B. L. Kalsotra, and R. K. Multani, J. Inorg. Nuclear Chem., 1974, 36, 1157. N. Kumar and R . K . Sharma, Chem. and I n d . , 1974, 261. G . V. Samsonov, A . N . Pilyankevich, A . F. Andreeva, and L. R. Shaginyan, Doklady Chem., 1973. 213, 844. R. Marchand and M . Tournoux, Compt. rend., 1973, 217, C, 863. R. von Schenck and H. Muller-Buschbaum, Z. anorg. Chem., 1974, 405, 197. H . Behrens, J. Ellermann, P. Merbach, and P. Weps, Z . Naturforsch., 1974, 29b, 469. H. Nakayama, C. Nishijima, and S. Tachiyashiki, Chem. Letters, 1974, 733. S. 0. Chan and L. W. Reeves, J. Amer. Chem. SOC.,1974, 96, 404.

Inorganic Chemistry of the Main-group Elements dissolved O,, however, and it has been concluded that in oxygen-free solutions T1' is mainly relaxed by transient spin-rotation interaction, and in oxygenated solutions by electron-nuclear dipole-dipole interaction. No T10, complexing need be postulated, however. TIN, is tetragonal at room temperature, but at 248*5 K it undergoes a transition to an orthorhombic form.5y3 1.r. and Raman spectra of a single crystal of TINO,-111 are consistent with the crystal space group being D:E-Pbnrn, with the NO; ions occupying sites of C, symmetry in the xy-planes and also perpendicular to them.594 Tl4P4O,, forms tetragonal crystals, in which the TI atoms are surrounded by 6 oxygen atoms in a distorted octahedral arrangement (Tl-0 distances 2.70-3.18 The two T1 atoms in the unit cell of T1' L-ascorbate are 4 . 0 5 A apart, bridged by 0 atoms.596 A new T1' uranate, Tl4UO5, has been made by careful heating of Tl,CO, + UO, under N,."' It dissociates above 230 "C to T1,O + T12U04,and it has been characterized by X-ray powder diffraction. The crystal structure of Tl(ZnS0,Cl) is built up from infinite layers of composition (ZnSO,Cl):-, held together by TI' ions.598The T1' ions are surrounded by 3 C1 and 6 oxygen atoms in an irregular manner (TI-Cl distances between 3.20 and 3.30 A, 5 T1-0 within the range 2.91-3.24 A, with the sixth 0 at a distance of 3.38A). Lattice constants have been tabulated for the ternary chalcogenides TlMX2, where M = Al, Ga, or In, X = S; or M = A1 or Ga, X = Se.599 Similar data have been recorded for T14GeS4,Tl,GeS,, and T1,Ge,S5.'"" TlFeS, and TlFeSe, may be prepared by melting together suitable ratios of the components to 300-500 "C.""' The T1-S distance in the former was found to be 3.314 A, as expected for an ionic interaction T1'- - .S2-. Two new modifications of TIInSz were formed by heating the I-form to high temperatures and pressures.6o2The 111-form has a structure consisting of sulphur layers (. . .ABBA.. .), with all the octahedral sites occupied by In, and 4 of the trigonal-prismatic sites by T1. The basic structural unit of T1' dimethyldithiocarbamate, T1S2CNMe2,is dimeric, and these units are joined by T1-S co-ordination to give layers parallel to the ab plane.6o3The TI atoms are seven-co-ordinate.

186

"" 4y4

""

Ty7 5yR

'" 'OO '("

'')'

"''

F. A . Mauer, C. R. Hubbard, and T. A. Hahn, J. Chem. Phys., 1973, 59, 3770. D. E. Pogarev and A. A. Shultin, Soviet Phys. Cryst.. 1Y73, 18, I Y 3 . J. K. Fawcett, V. Kocman, and S. C. Nyburg, Actu C r y s t . , 1974. B30, 1979. D. L. Hughes. J.C.S. Dalton, 1973, 2200. A . S. Giridharan, M. R. Udupa. and G. Ararnavudan, Z. anorg. Chem.. 1974. 407, 345. B. Bosson. A c t a Chem. Scand., 1973, 27, 2230. D. Muller, F. E. Poltmann, and H. Hahn, Z. Naturforsch., 1974, 29b, 117. G. Eulenberger and D. Muller, Z. Naturforsch., 1974, 29b, 118. A. Kutoglu, Naturwiss., 1974, 61, 125. K.-J. Range, G. Engert, W. Muller, and A. Weiss, Z. Naturforsch., 1974, 29b, 181. P. Jcnnische and R. Hesse, A c t a Chern. Scand., 1973. 27, 3531.

Elements of Group I11 187 A very similar situation is found for diethylthioselenophosphinatothallium(I), Tl(Et,PSeS) .604 Again the molecules are dimeric and linked together to give polymeric layers. The dimeric unit is shown in Figure 25. Crystals of TlF are orthorhombic, belonging to the space group Pm2a.605 There are two types of TI atom with unsymmetrical environments, showing that there are significant lone-pair distortions in this system.

Figure 25 The molecular structure of the [Tl(Et,PSeS)], dimer (Reproduced by permission from Acta Chem. Scand., 1973, 27, 3355) Analysis of the electron scattering by the TlF dimer suggests a value for the instantaneous dipole moment of several debye.606This is not consistent with a stiff, symmetric, linear structure for the dimer. Pure TlMnF, can be obtained in good yield from solutions of excess TlF and MnF, in dilute HF.607 Thallium(1) forms precipitates (TlX) and soluble complexes (TlX;) with the anions C1-, Br-, I-, and Ng in dimethylacetamide as solvent. Formation constants have been calculated for all of these species.6o8 Thallium(1) tetracarbonylcobaltate has been prepared by metathesis of Na[Co(CO),] with T1' salts in H20, by metal exchange, Hg[Co(CO),], + 2T1, Other T1' compounds, e.g. and by reduction of Tl[Co(CO),], by T1 Tl[M(CO),Cp] (M = Cr, Mo, or W), have also been isolated, while there is spectroscopic evidence for the existence of TI[CO(CO)~PP~,]and Tl[Mn(CO),]. The stabilities of these TI' compounds towards disproportionation are in the order: Co(CO), >> M(CO),Cp (W > Mo > Cr) > Co(CO),PPh, - Mn(CO),. All of the T1"' analogues are known, but some of h04 h05 'I'

S. Esperis and S. Husebye, Acta Chem. Scand., 1973, 27, 3 3 5 5 . N. W. Allcock and H. D. B. Jenkins, J.C.S. Dalton, 1974, 1907. M. G. Fickes, R. C. Slater, W. G. Becker, and R. C. Stern, Chem. Phys. Letters, 1974, 24, 10.5.

'07

6OR 'OY

G. S. Rao and S. K. Gupta, Indian J. Chem., 1973, 11, 956. M. Brkant, J.-P. Nicolas, S. Alam, and M. Levergne, Compt. rend., 1973, 277, C, 85.5. J . M. Burlitch and T. W. Theyson, J.C.S. Dalton, 1974, 828.

188

Inorganic Chemistry of the Main -group Elements

them, especially Tl[Mn(C0)5]3, readily undergo light-promoted reductive elimination to the corresponding T1' compound. The crystal structure of TlCo(CO), as determined by X-ray diffraction, consists of discrete T1' and [Co(CO),]- ions arranged in an NaC1-like array.61nIn low-dielectric solvents, however, TlCo(CO), exists as a tight ion pair, with some TI-Co covalent bonding. With excess [Co(CO),]-, the complex Tl[Co(CO),]; is formed. In solvents of high dielectric constant, the reactions of TlCo(CO), are consistent with the presence of free ions. Tl,HgBr, crystallizes in the tetragonal space group P4/rnnc. HgBr, octahedra are present, with interstitial TI' ions.'" Tl,HgCl, could not be prepared, Tl,,Hg,Cl,, always being produced. Reduction of (CsHs)Tl"'C1 with potassium metal gives K'[CsH,T1']-."" Phase studies on T1' systems have been reported in refs. 613-624.

Other Thallium Compounds.-Tl'' ions may be generated by flash photolSome of their redox reactions have been studied, ysis of Tl'l' and they give values of the standard reduction potentials for the reactions:

+ e- e TI2+ T12' + e- e T1' Tl"

of +0.33 f0.05 and +2.22 f0.05 V, respectively. The disproportionation reaction :

has a rate constant of (5.5 f0.5) x 10, 1 mol-' s-l at 25 "C. Further studies on the T12' ion, similarly produced, including rate constants of a number of its reactions, have also been reported by Schwarz et a1.626 610

6"

612 613

'I4

'I5 6'6

618

'Iy hZ(1

621

"*

''' 024

'*' 626

D. P. Schussler, W. R . Robinson, and W. F. Edgell, Inorg. Chem.. 1974. 13, 153. K. Brodersen, G . Thiele, and G . Giirz, 2. anorg. Chem., 1973, 401, 217. N . Kumar and R . K. Multani, J. Organometallic Chem., 1973, 63, 47. A. Schiraldi, A . Magistris, and E. Pemati, Z. Naturforsch., 1Y74, 29a, 782. C. W. F. T . Pistorius, J. Chem. Phys., 1974. 60,3720. 1. N . Belyaev, T. G. Lupeiko, and G . P. Kirii, Russ. J. Inorg. C h e w , 1973, 18, 71 1. M . S. Kabre, M. Julien-Pouzol, and M. Guittard. Bull. SOC.rhim. France, 1974, 1881. J.-C. Cretenet, Rev. Claim. minirale, 1973, 10, 399. A. Vedrine, R. Boutonnet, and J.-C. Cousseins, Compt. rend., 1973, 277, C, 1129. H . J . Seifert. T. Krimmel. and W. Heinemann. J. Thermal Analysis. 1974. 6, 175. V . V . Safonov, V . A. Grin'ko, M . B . Varfolomeev, €5. S. Malysheva, and V . I . Ksenzenko. Russ. J. Inorg. Chem., 1973, 18, 1503. V. V . Safonov and 0. V. Lemeshko. Russ. J. Inorg. Chern.. 1973, 18, 1035. R . P. Lagutova, D. G. Barsegov, A. G. Yakovlev, and I . I . Il'yasov, Russ. J. Inorg. Chem.. 1973, 18, 760. V . V. Volchanskaya and I . 1. Il'yasov, Russ. J. Inorg. C'hom., 1973, 18, 1041. I . I . Il'yasov and Yu. G . Litvinov, Russ. J. Inorg. Chem., 1973, 18, 1788. B. Falcinella, P. D. Felgate, and G. S. Laurence, J.C.S. Dalton, 1Y74, 1367. H . A . Schwarz, D. Comstock, J . K. Yandell, and R . W. Dodson, J. Phys. Chem., 1974, 78, 488.

Elements of Group 111 189 The effect of C1- on the electronic spectrum of TI" produced by pulse radiolysis indicates that the species TlCl', T1C12, and TlCl; are all present. Rate constants for a number of reactions of these chloro-species have been rep~rted.~" The phase diagram of the TI-S system reveals the existence of the following phases: Tl,S, TLS,, TlS, and T1,S,.628TI& forms monoclinic crystals in which one Tl"' atom is tetrahedrally co-ordinated by S atoms, and also interacts with 3 T1' ions.629This interaction is thought to be electrostatic in nature. 627 628 629

R . W. Dodson and H. A. Schwarz, J. Phys. Chern.,,1974, 78, 892. S. Kabre, M. Guittard, and J . Flahaut, Compt. rend., 1974, 278, C, 1043. B. Leclerc and M. Bailly, Acta Cryst., 1973, B29, 2334.

Elements of Group IV ~~~

BY P. G. HARRISON AND P. HUBBERSTEY

1 Carbon The limits pertaining to the inorganic chemistry of carbon are difficult to assess. Following the pattern adopted in previous Reports, the data collected here have been restricted to those describing the chemistry of the carbon allotropes and of the non-catenated molecular carbon species, particularly those containing carbon-non-metal (i.e. hydrogen, nitrogen, phosphorus, oxygen, sulphur, and halogen) bonds. The carbides are omitted since there are no published data on the Main-group element carbides; the carbaboranes are also omitted since they are considered in full in Chapter 3. A further section of Gmelin’s Handbook of Inorganic Chemistry relating to carbon has been published;’ in it the chemistry of partly or completely halogen-substituted derivatives of CH, CH,, and CH,, as well as the perhalogenated methanes, is described. Halogenomethanes containing hydrogen are not covered. A new technique for carbon analysis based on X-ray fluorescence has been devised.’ Although X-ray fluorescence of light elements such as carbon corresponds to energies too low to be excited by classical equipment, by using a mixed photon-slow-electron tube, longer wavelengths ( >20 A), suitable for light-element excitation, can be achieved without notable technological constraint. It has .been concluded3 from the results of chemical analytical experiments that much of the carbon found in lunar soils has been modified since accumulation by the energetic events that cycle lunar soils; i.e. the rate at which extralunar carbon is accumulated from the solar wind and meteorite bombardment is slow compared to that at which it is redistributed by particle erosion and aggregation. A number of theoretical investigations of the electronic structures of small carbon-containing molecules have been ~ n d e r t a k e n The . ~ ~ relative Gmelin’s Handbook of Inorganic Chemistry, System 14, Carbon Part 11, Section 2, SpringerVerlag, Berlin, 1974. * R. vie le Sage, P. Bocquillon, and J. Faucherre, Cornpt. rend., 1974, 279, C, 125. D. J. Desrnaryis, J. M . Hayes, and W. G. Meinschein, Nature. Phys. Sci.. 1974. 246, 6 5 . V. I. Nefedov, N. P. Sergushin, I. M. Band, and M. B. Trzhaskovskaya, J. Electron Spectroscopy, 1973, 2, 383. ’ W. B. Perry and W. L. Jolly, Inorg. Chew., 1974, 13, 121 1. D. R. Armstrong, P. G. Perkins, and J. J. P. Stewart, J.C.S. Daiton, 1973, 2273.

‘

190

191

Elements of Group IV

intensities of X-ray photoelectron spectra (X.P.S.) bands corresponding to, inter alia, carbon and silicon core electrons have been calculated and compared with experimental values ;4 satisfactory agreement is obtained for the 1s levels in, inter alia, CF,, CO, COz, and CO:-. Experimentally determined core-electron binding energies have been correlated with calculated charge distributions for compounds of carbon (Is), silicon ( 2 p ) , and germanium (3p,,J.’ Carbon (1s) binding energies vary from 290.31 for C(CH,), to 301.68 eV for CF,. Calculations have been performed within the CNDO MO SCF framework on a wide range of molecules containing elements of the first and second rows of the Periodic Table, including carbon and silicon6 Valencies of all atoms, anisotropies (a measure of the non-spherical distortion of an element’s electronic environment) of some of the atoms, and bond indices for bonds in selected molecules have been calculated. Appropriate data are collected in Table 1. The valeocy of Table 1 Valencies, anisotropies, and bond indices in carbon -containing rno lecules Carbon valency 2.94 2.61 3.86 3.93 3.95 3.94 3.98 3.98 4.00 3.53

Carbon anisotropy 0.74 0.82 0.00 0.02 0.00 0.04 0.16 0.00 0.00 0.25

Bond C-N c-0 c-0 c-0 C-H

C-B

c-0

Bond order 2.94 2.61 1.93 1.31 0.99

1.oo 2.38

carbon in most of the compounds studied is calculated to be ca. 3.9 (Table 1); notable exceptions are CN- and CO, where values are 2.9 and 2.6, respectively. The latter values and their tendency to increase account for the donor properties of these species and their ability to complex to transition-metal ions. It is noteworthy that both nitrogen and oxygen in these species have high valencies; hence the mode of attachment of CO in metallic carbonyls is not surprising.6 Carbon Allotropes.-Thermodynamic functions of single-crystal graphite have been assessed in the t’emperature range 0-3000 K7The experimental specific .heats have been described by a computer-fitted single equation; enthalpies, entropies, and free energies have also been calculated. Galimov’s cavitation hypothesis’ for the formation of natural diamonds has been refuted by Frank et al.” on the basis of the kinetics of crystal

’ N . V. Markelov, V. I. Volga, and L. M. Buchnev, ’ E . M . Galimov, Nature, 1973, 243, 389.

’ F. C. Frank, A. K. l,ang,

Russ. J . Phys. Chem., 1973, 47, 1025.

and M . Moore, Nature, 1973, 246, 143.

192

Inorganic Chemistry of the Main-group Elements growth and martensitic conversion. It is conceded, however, that although it is inconceivable that the recognized diamonds for which mines are worked were produced by Galimov’s process, the formation of microdiamonds by this process is possible. The postulate” that natural diamonds were formed by a reduction of CO, by pyrrhotite in reactions such as (1) has been tested experimentally by oxidizing natural diamonds by pure oxygen at high temperature .” 2FeS(c) + CO,(g) + 2FeO(soln.) + S,(g) + C(diamond)

(1)

Diamonds formed by this route would contain inclusions containing either free sulphur, or sulphur compounds7 or both; on oxidation, gaseous sulphur oxy-compounds would be formed, which could be detected mass spectrometrically. No evidence of sulphur was found, and so this proposed route to natural diamond is not thought to be responsible for the formation of all natural diamonds. The data are limited by the amount of diamond oxidized (16g), and so the possibility of some diamond formation by this route cannot be ruled out.” A new method of nucleating synthetic diamonds in the size range
‘ I

Elements of Group IV

193 A review of the graphitization of carbons, containing 183 references, has been published.” The influence of doping by boron on the graphitizatisn of carbons has been the subject of an exhaustive investigation;” a new mechanism for the graphitization process has been developed.2’ Structural Studies. In a number of communications,’’-26 correlations have been sought between both the spectroscopic and chemical properties of the various carbon allotropes and their structures. Thus, an electron-energy-loss spectroscopic study” of diamond, graphite, and amorphous carbon has shown that the differences in the K-shell ionization loss spectra of the three allotropes (Figure 1) might be the basis of a technique for distinguishing

1

li R“

DIAMOND

GRAPH I TE

AMORPHOUS

0

320

3 to

Energy loss of primary electron ( i n eV)

Figure 1 K-Shell ionization-loss spectra of diamond, graphite, and amorphous carbon (Reproduced by permission from J. Electron Spectroscopy, 1974, 3, 232) 2”

’’ 22

23 24 25

”

A. Pacault, Carbon, 1974, 12, 1. J.-P. Rouchy and J. Merine, Compt. rend., 1973, 277, C , 533. R . F. Egerton and M. J . Whelan, J. Electron Spectroscopy, 1974, 3, 232. M. Nakamizo, R. Kammereck, and P. L. Walker, Carbon, 1974, 12, 259. R. R. Saxena and R. H. Bragg, Carbon, 1974, 12, 210. G. B. Engle, Carbon, 1974, 12, 291. C.-H. Pons and D. Tchouber, Compt. rend., 1973, 277, €3, 679.

194

Inorganic Chemistry of the Main-group Element between different forms of the same element. Since the technique has high spatial resolution, it is applicable to microscopic quantities (lo-’‘ g). The Raman spectra of a number of natural graphites and carbonaceous materials, including pyrolytic graphite, carbon black, glassy carbon, coal, ‘white’ carbon, and sputtered carbon, have also been studied.23All spectra contained two bands (at 1580 and 1360cm-’) with the exception of that of natural graphite, which had a single sharp band (at 1580 cm-I). The relative intensity of the 1360cm-’ band to that of the 1580cm-’ band and its half-band width increased from graphite through glassy carbon to carbon black. Both sputtered carbon and ‘white’ carbon showed an additional band near 2140 cm-’; this band is thought to originate from conjugated acetylenic (--C-=C-), bonds. Evidence for similar bonding has been observed2’ in the electronic and i.r. spectra of the acetone-soluble portion of cokes formed in the catalytic cracking of n-pentane and isopentane vapours. The bonding character of a number of glassy (vitreous) carbons heattreated to 1000, 1800, and 2800°C for an hour has been studied by comparison of their K-emission spectra with those of diamond and pyrolytic g r a ~ h i t e . ~The “ peak wavelength of glassy carbon lies between those of diamond and pyrolytic graphite, suggesting two possibilities: (i) in glassy carbon the bonding character at each carbon is intermediate to the two extremes, or, (ii) that glassy carbon contains both trigonal and tetrahedral C-C bonds. In view of the layered structure of glassy carbon, shown in a separate wide- and low-angle X-ray-diffraction investigation” to be based on hexagonal graphite-like sheets with no graphitic registration between sheets, postulate (i) is excluded. Thus the shift in peak wavelength of glassy carbon towards pyrolytic graphite with higher heat-treatment temperature shows that the amount of tetrahedrally bonded carbon reduces with increasing heat-treatment temperature .24 The structural properties of a number of glassy carbons prepared by pyrolysis of copolymers of furfuryl alcohol and ferrocene derivatives have been e l ~ c i d a t e dIn . ~the ~ early stages of pyrolysis a highly dispersed state of iron in the carbonaceous matrix was produced. Later on, the homogeneously dispersed iron separated into irregularly spaced domains consisting of cementite, pure iron, and iron compounds of unknown composition. Additional evidence has been provided by Russian workers3’ that both synthetic carbyne and the natural mineral chaoite (‘white’ carbon) consist of at least two modifications. Information has also been obtained recently regarding the conditions under which carbyne and chaoite are formed; it is concluded that these modifications are not as uncommon as previously thought .30 27

” 29

K. H . Karmarker and G. N . Natu, Spectrochim. Actu, 1974, 30A, 547. G . D. Wignall a n d C. J. Pings, Carbon, 1974, 12, 51. R. Kammereck, M. Nakamizo, and P. I<. Walker, Carbon, 1974, 12, 281. V. I . Kasatochkin, V. V. Korshak, Yu. P. Kudryavtsev, A . M. Sladkov, and V. M. Elizen. DokIady Chem., 1974, 214, 84.

Elements of Group IV 195 Chemical Studies. The chemical reactivity of carbons and graphites is profoundly influenced by the presence of surface functional groups. Several investigations of the structure and reactivity of these surface complexes have been ~ n d e r t a k e n , ~ lincluding -~~ a study of the influence of hydrogen chemisorption on the subsequent chemisorption of oxygen on activated g r a p h ~ n . ~The ' decomposition of graphite-oxygen surface complexes has been studied using a gas-flow apparatus with i.r. detection of CO and CO,.', The oxygen is chemisorbed on four types of sites, forming surface complexes which on decomposition give mainly CO and CO,. The first two types of sites (A, B) are formed by 'labile' carbon atoms created during the initial degassing period. These sites disappear without reconstitution upon desorption of the complexes. These other two sites (C, D) are formed by edge carbon atoms. C-sites form by oxidation only at temperatures below ca. 950 "C;D-sites form at higher temperatures. In a parallel i n ~ e s t i g a t i o n ~ ~ of the absorption of water on previously degassed graphite it has been shown that chemisorption is appreciable above 200 "C. A surface complex is formed which decomposes at higher temperatures with simultaneous evolution of CO and H2. Decomposition was found to occur in two stages; the first corresponds to the disappearance of those sites that cannot be reconstituted (A, B), whereas the second corresponds to the removal of those sites which can be renewed after degassing ( C , D). Those surface oxygen complexes on Spheron 6 which thermaily desorb as CO, are thought to be responsible for the acidity of the carbon.34Two types of acidic oxide have been observed. An oxide which acts as a very weak monobasic acid is decomposed at ca. 250 "C whereas a second oxide, which is a stronger dibasic acid, is decomposed at ca. 600 "C; these two structures are unIike those found on graphite, which decompose at ca. 400°C and have different acidic properties. Parallel investigations of the interactions of NO,3' and SO,36with adsorbent carbons have shown that the efficiency of both processes is dependent on the concentration of unsaturated sites on the surface of the carbon. Passage of N02-N, mixtures3' over previously degassed charcoal involves appreciable reduction of the gas. A major proportion of the oxygen so produced is chemisorbed by the carbon, the remainder causing combustion and the formation of free CO,. The optimum reaction temperature is 400 "C. Interaction of SO,-N, mixtures takes place at temperatures above 300 "C (optimum 600 "C) and involves fixation of sulphur by the carbon and to some extent the formation of free sulphur as well as H2SO4 and H,S through interaction with the surfaces of the carbon. A n appreciable amount I' 32 33 34

3s 3h

R. C. Bansal, F. J. Vastola, and P. L. Walker, Carbon, 1974, 12, 355. P. Magne and X. Duval, Carbon, 1973, 11, 475. P. Magnc, R. Sauvageot, and X. Duval, Carbon, 1973, 11, 485. S. S. Barton, D. Gillespie, and B. H. Harrison, Carbon, 1973, 11, 649. B. R. Puri, R. C. Bansal, and S . S. Bhardwaj, Indian. J. Chern., 1973, 11, 1168 B. R. Puri, R. C . Bansal, and S. S . Bhardwaj, Indian J. Chem., 1073, 11, 1170.

196

Inorganic Chemistry of the Main-group Elements of C 0 2 is also evolved in the process. In contrast to the NO, reaction, which is restricted by the chemisorption of oxygen at the unsaturated the capacity of the carbon for the SO, reaction is dictated by the formation of a C-S solid complex at these The catalytic hydrogenation of carbons has been the subject of two investigation~.~"~~ Catalysis by Ni, Pt, and Rh has been studied at a series of constant temperatures between 400 and 1050 "C3' The reaction was found to occur in two distinct stages; half of the carbon was rapidly gasified to CHI, the remainder being gasified at a very low rate. It is suggested that the carbon reacting initially may be amorphous, a more crystalline fraction taking part in the slower reaction. The catalytic effects of metallic impurities on the reactivity of graphite towards both H, and H,O have been investigated in the temperature range 25-1 100 "C as a function of the impurity oxidation The reaction of graphite with dry H, is catalysed by metallic Fe, Co, and Ni. The metals Mn, Cr, Mo, and V show a slight catalytic effect at temperatures close to lOOO"C, whereas Cu, Zn, Cd, Ag, and Pb are inactive. Fe, Co, and Ni are active catalysts for the graphiteH 2 0 reaction between 600 and 1000°C provided that the metal is kept in the reduced state by means of added H,. V and Mo are weak catalysts under these conditions whereas Cu, Zn, Cd, Ag, Cr, Mn, and Pb are inactive. In the absence of H2 the metal remains in the higher oxidation states, and the catalytic activity of all these impurities is low or negligible.'" The oxidation of carbon allotropes has been the subject of a number of investigations; although the majority are associated with simple graphites, the oxidation of carbon fibres" and highly oriented stress-recrystallized pyrolytic graphite~"~."' has also been studied. Microscopic examination of two oxidized samples of these particular pyrolytic graphites revealed some unusual feature^.^' Attack occurs on the basal plane surfaces at defects that are thought not to be non-basal screw dislocations, but which may be associated with some structural irregularity introduced during dep~sition.~' Three papers describing the results of controlled-atmosphere electron microscopy studies of the oxidation of graphite have been published;4244 the behaviour of Pb,12 M O T M003,13and Ag4" as catalysts and the general morphology of the reaction have been investigated. It is suggested that intercalation of MOO, might play a role in the exfoliation of the graphite sheets."' The effect of a B-P-Si oxidation inhibitor on the gas-phase oxidation of graphite has also been studied, using a number of different '' A. Tomita,

N. Sam, and Y . Tamai, Carbon, 1974, 12, 143.

'' D. W. McKee, Carbon, 1974, 12, 453. 3y 40 41 42 43 44

0. P. Bahl and L. M. Manocha, Carbon, 1974, 12, 417. F. Rodriguez-Reinoso, P. A. Thrower, and P. L. Walker, Carbon, 1974, 12, 6 3 . F. Rodriguez-Reinoso and P. A. Thrower, Carbon, 1974, 12, 269. P. S. Harris, F. S. Feates, and B. G . Reuben, Carbon, 1973, 11, 5 6 5 . R. T. Baker, P. S. Harris, D, J. Kernper, and R. J. Waite, Carbon, 1974, 12, 179. P. S. Harris, F. S. ,Feates, and B. Ci. Reuben, Carbon, 1974, 12, i8Y.

Elements of Group IV 197 graphite sub~trates.~’ Oxidation of graphite by ozone in both the gas phase46 (1-5% 0,-0, mixtures) and solution4’ (in H,O and in CC1,) has been was found to be examined. The main process in the gas-phase resulted in irreversible chemisorption of 0,; that in the solution gasification of carbon as CO, and fixation of oxygen as CO and CO, surface complexes. The CO, complexes are of the acidic and neutral types. The kinetics of the C-CO, reaction have been analysed in a number of recent publication^.'^-^^ In one of these, the oxidation of carbon in metallic melts (Fe-C and Ni-C) by exposure to a C0,-N, gas stream has been monitored.” The reaction can best be rationalized by a combination of the two consecutive steps (2) and (3)’ in which the CO, is reduced at the metal surface to give CO and adsorbed oxygen, (O),,,, which then reacts with soluble carbon, (C)m,to form CO.”

co, + co + (O), An experimental study of the reaction (4) has demonstrated that the oxidation is linked to the nature of the carbon;’l it is not possible to accept the suggestion that the reaction depends solely on the transformation between the two crystal forms of silica. 8i0, + 3C -+ S i c + 2CO

(4 )

Graphite Intercalation Compounds.-Considerable effort is still being applied in order to further the understanding of graphite intercalation c6mhave described three new synthetic routes to the pounds. Lagow et al.52*53 ‘non-conducting’ intercalation compound poly-carbon monofluoride, (CF, ),. The limiting stoicheiometry achieved, CF1.12+0.03, which is greater than the previously reported maximum (CF,,98), implies the presence of CF, groups around the edges of the cyclohexane rings. Careful control of the reaction temperature (627 f 3 “C) was found to be essential to obtain reproducibly the completely fluorinated white product. CF,.,, was found to be one of the most thermally stable fluorocarbon polymers, in contrast to previous reports describing the material as unstable and explosive. In the same communication, Lagow et aLs3describe the preparation of tetracarbon monofluoride, C4F, by a high-pressure bomb technique. 45 46

47

48 49

’’ 52

53

R. W. Wallough and E. A. Heintz, Carbon, 1974, 12, 243. N. I. Kobozev, G. I. Emel’yanova, and L. F. Atyaksheva, Russ. J . Phys. Chem., 1973, 47, 1236. B. R. Puri, R . C. Bansal, U. K. Aggarwal, and S. S. Bhardwaj, Indian J. Chem., 1973, 11, 1020. A . Lowe, Carbon, 1974, 12, 335. P. Wehrer, X . Duval, and R. Sauvageot, Carbon, 1974, 12, 71. I. S. Bystrova and 0. V. Travin, Russ. J. Phys. Chem., 1973, 47, 1037. R. Frernont-Larnouranne and H. Guerin, Bull. Soc. chim. France, 1974, 6. R. J. Lagow, R. B. Badachhape, J. L. Wood, and J. L. Margrave, J . Amer. Chem. Soc., 1974, 96, 2628. R. J. Lagow, R. B. Badachhape, J . L. Wood, and J. L. Margrave, J.C.S. Dalton, 1974, 1268.

Inorganic Chemistry of the Main-group Elements

198

The fluorination of the other 'non-conducting' intercalation compound, graphite oxide, has been achieved with the formation of the new compound, graphite o~yfluoride.'~ It is light grey, reactive, and it decomposes at ca. 50 "C to yield a yellow-brown powder. The catalytic properties of graphite oxide have also been considered, with particular reference to the degradation of organic material^.'^

Alkali Metals. Hkrold et al.55have prepared a new type of intercalation compound by the action of heavy alkali metals on the ternary KC&,,. This latter compound is best considered as a second-stage compound in which alternate gaps between the carbon layers are empty, the other gaps containing a double layer of K atoms, the adjacent carbon layers being a distance C

c

C

C C C

c

t

13.35 A

C

(4)

C M K Rb

XlA 5.27 5.62 5.92

cs

(5)

of 8.53A apart (3). The corresponding distances in graphite (4)and the first-stage compound KCs (1) are 3.35 and 5.32 A, respectively. The formation of KC,H,,, from KC, by the action of H2 necessarily involves passage from a first- to a second-stage compound; a simple mechanistic pathway has been proposed and is shown schematically in (2). The insertion of more alkali metal into the gaps of KC8H,,, readily occurs to give the new type of intercalation compound of general formula K,C,H,,,,MC, (M = K, Rb, or Cs) (5). Hkrold'" has also studied the paramagnetic susceptibility of the ternary compounds K,Cs,-,Cs (0 S x S 1) as a function of x ; a maximum in the susceptibility was observed at a composition close to x = 0.5. 54

55 56

A. Tomita, Carbon, 1974, 12, 92. P. Lagrange, A. MCtrot, and A. HCrold, Compt. rend., 1974, 278, C, 701. G. Furdin, B. Carton, D. Billaud, C. Zeller, and A. HCrold, Compt. rend., 1974,278, R, 1025.

Elements of Group IV

199

Halogens, Halides, and Oxides. The fascinating possibility that a second- or higher-stage intercalation compound of high thermal stability might react with a different intercalatable species at low temperature to yield a mixed layer complex has been realized by F ~ e e m a n ; ~a’ fourth-stage graphiteFeCl, compound was treated with N,O, at 0 ° C with the formation of a doubly filled graphite-FeCl,-N,O, intercalation compound (6) of empirical formula C,,Fe CI3(N,O5)I.7.

Intercalation of bromine has been the subject of two complementary

investigation^.^^^^^ Direct observation of bromine penetration into a pyrocarbon sample has been effected using an electron m i ~ r o p r o b e The . ~ ~ results show that (i) bromine diffusion occurs only along the graphitic layers, (ii) the bromine front is very sharp, and (iii) a fully intercalated compound is formed behind the bromine diffusion front. The intercalation is thus interpreted as a two-step process which involves initially the movement of the bromine front through the sample along the graphitic layers; the nearly complete compound formed behind the front is then transformed by a simple diffusion process into a fully intercalated one.s8 A vapour-pressure investigation of the graphite-Br, system has shown both continuous changes between the definite stages and a large hysteresis in the brominationdebromination process.59 Since X-ray studies have also shown that compounds of composition between definite stages possess a structure composed of microdomains of both of the two stages, and, in agreement with the above investigation, the structural transformation and the hysteresis phenomena have been interpreted assuming the compound to possess a conglomerate structure of micro domain^.^^ Studies over a wide temperature range have shown that insertion in graphite is much less frequent for bromides than for chlorides; insertion of 57 58

A. G. Freeman, J.C.S. Chem. Camm., 1974, 746. A. Marchand and J. C. Rouillon, Carbon, 1973, 11, 666.

59

T. Sasa, Carbon, 1973, 11, 497.

200

Inorganic Chemistry of the Main - group Elements

iodides has not been achieved.6" Insertion of AlBr, has been confirmed and the compounds of graphite with GaBr, and AuBr, have been synthesized; in general, insertion is favoured by the presence of free bromine and leads to graphite-bromide-bromine ternary compounds.60 SbF, has been intercalated in graphite by heating a mixture of the two components at 110 "C for several days.61The product exhibits much improved resistance to hydrolysis and is considerably easier to handle."' The reactivity of AlCl, has also been found to be reduced on intercalation, since the intercalate is a much milder Friedel-Crafts catalyst than AlCl,, giving less polysubstituted reaction products.,, Hohlwein and Metz6, have carried out an X-ray diffraction study of the graphite-FeC1, system; they claim that the observed line shifts and line broadenings are incompatible with the previously adopted simple 'stage' model. By assuming a one-dimensional disorder of composition, however, and by comparing the experimental and calculated diffraction patterns, it has been possible to identify the type and extent of the 'disorder in this system. The exfoliation of FeC1, intercalates has been studied in the temperature range 800-1500 "C using a number of graphite specimens.64 In every experiment some of the FeC1, was reduced to a - F e . The postulated mechanism includes as first step (5), the thermal decomposition of Fe,Cl,(g)

-+

2FeC12(c)+ Cl,(g)

(5)

FeCl,; the FeCl, so formed then undergoes a disproportionation reaction (6), the overall reaction being the thermal decomposition of FeC1, (7). The 3FeC12(c)+ Fe,Cl,(g) FeCl,(c)

-+ Cl,(g)

+ Fe(c)

+ Fe(c)

(6)

(7)

electrical conductivity of a range of intercalates from the graphite-FeC1, system has been measured as a function of temperature and composition along both axes65(parallel and perpendicular to the graphitic planes). T6e parallel conductivity dec5eases systematically with increasing FeCI, content whereas the perpendicular conductivity passes through a minimum at ca. 55% FeCl,. X-Ray diffraction, thermal, and chemical methods have been used to demonstrate that CrO, will intercalate into graphite in the presence of glacial acetic acid."" The product is a third-stage ionic compound C13.8Cr03.75H [ = Cf~.,(CrO,),(CrO~~)(H,O),], which may be hydrolysed to give a molecular intercalate C,,.,CrO,.,,H, ( = C92.4Cr30, ,H,), the hydrolysis 60

C . Balestreri, R. Vangelisti. J . Melun, and A. HCrold, Cornpl. rend.. 1971, 279, C: 279. J.-M. Lalancette and J . Lafontaine, J.C.S. Chem. Comrn., 1973. 815. '' J.-M. Lalancette, M.-J. Fournier-Breault, and R. Thiffault. Canad. J. Chem., 1974, 52, 589. '' D. Hohlwein and W. Metz, Z . Krist., 1974, 139, 279. 64 R. E. Stevens, S. Ross, and S . P. Wesson, Carbon, 1973, 11, 525. '' J.-F. Boissonneau and G. Colin, Carbon, 1973, 11, 567. hh L. B. Ebert, R. A. Huggins, and J . 1. Brauman, Carbon, 1974, 12, 199. "

Elements of Group IV 20 1 involving removal not only of all Cr0:- ions but also of some of the CrO, from the compound. Contrary to previous reports, results show that CrO, and graphite do not react to form an intercalation compound, but yield instead a mixture of lower oxides of chromium and unreacted graphite.66 Methane and its Substituted Derivatives.-As a result of the molecular simplicity of these compounds, a large percentage of the published data in this section is associated with their theoretical, structural, and spectroscopic properties. Theoretical Studies. A total of seven theoretical analyses of the electronic ~ of these the structure of methane have been ~ n d e r t a k e n . ~In~ a- ~number results are compared with those for either the halogenomethanes CH,F4-, (0 d n 5 4),”,” CH3C1,72CH2C12,72or the isoelectronic ions BH; 73 and NH:.’, The electronic structures of CF,74 (in the isoelectronic series BeF:-, BF;, CF,) and CH,NO” have also been determined. Equilibrium molecular geometries have been calculated theoretically for CH,OH,’“ CH3SH,77CH3PH2,” CH,SiH,,” and CF,NCO;” in general, they agree with experimentally determined data. An interesting feature of CF3NC0, however, is the fact that the -NCO group is found to be non-linear (similar results are obtained for SiH,NCO). The barriers to internal rotation and dipole moments of CH,SH, CH,PH2, and CH,SiH, have also been c a l ~ u l a t e d . ~ ~ The geometrical structure of the ionic intermediate CF; ’’ has been shown to be based on a CF,-F- configuration with a C-F distance of 2.58 a.u. in the tetrahedral CF, and a CF4-F- distance of 5.80 a.u. from the results of ab initio calculations taking into account all 52 electron^.'^ An MO simulation of the oxidation of methane” has shown the geometry of the CH,O, radical intermediate to have r ( 0 - 0 ) = 1.19 A and LCOO = 11lo, with fixed distances of r(C-0) = 1.44 8, and r(C-H) = 1.09 A. The results of three theoretical studies of the CH,NC isomerization have been p ~ b l i s h e d . ~ ’Moffatt -’~ and Tang’’ have derived a complete potentialenergy surface which shows an energy minimum for a pyramidal CH, group

‘’ A.

D. Tait and G. G. Hall, Theor. Chim. Acta, 1973, 31,’311. R. Montagnani, P. Riani, and 0. Salvetti, Theor. Chim. Acta, 1973, 32, 161. J. J. Eberhardt, R. Moccia, and M. Zandomeneghi, Chem. Phys. Lelters. 1974, 24, 524. 70 P. S. Bagus, M. Krauss, and R. E. Lavilla, Chem. Phys. Letrers, 1973, 23, 13. 7’ B. Levy, Ph. Millie, J. Ridard, and J. Vinh, J. Electron Spectroscopy, 1974, 4, 13. ’* D. B. A d a m and D. T. Clark, Theor. Chim. Acta, 1973, 31, 171. 73 J. R. Easterfield and J. W. Linnett, J . C . S . Faraday JJ, 1974, 70, 317. 74 B. F. Shchegolev, E. L. Rozenberg, 0. P. Charkin, and M. E. Dyatkina, J. Struct. Chem., 1973, 14, 542. 7 5 T.-K. Ha and U. P. Wild, Chem. Physics, 1974, 4, 300. ’’ E. Taillandier and D. J . David, Chem. Physics, 1974, 4, 157. 77 M. S. Gordon and L. Neubauer, J. Amer. Chem. SOC.,1974, 96, 5690. B. M. Rode, W. Kosmus, and E. Nachbaur, Monatsh., 1974, 105, 191. 7y S.-J. Wang, Z. Naturforsch., 1973, 28a, 1832. an K . Ohkubo and F. Kitagawa, Bull. Chem. SOC.Japan, 1973, 46, 2942. J. B. Moffat and K. Tang, Theor. Chim. Acta, 1973, 32, 171. a2 C. J . Steed and H. H. Harris, J. Chem. Phys., 1974, 60, 1355. a3 D. L. Bunker and W. L. Hase, J. Chem. Phys., 1973, 59, 4621. “ 69

202

Inorganic Chemistry of the Main-group Elements placed at ca. 90" to the CN axis. The barrier to the isomerization has been calculated as 32.9 kcal mol-' (cf. 38.4 kcal mol-' experimental). A charge separation equivalent to (CH:o.22)(CN-0.22)is found for the intermediate and (CH:o.'2)(NC-0.'2) for the cyanide and compared to (CHfO08)(CN-o.08) isocyanide, respectively." Structural Studies. Geometrical parameters of a number of substituted methanes have been determined using various techniques, including microwave spectroscopy and electron and X-ray diffraction. Microwave data for various isotopic species have led to the structures of CH3PF2 (7),84 cis-CH,OPF, (8),"' and CH,SCl (9).86

The three-fold axis of the CH, group is at 3.69" to the C-S bond

The three-fold axis of the CH, group is assumed to be along the C-0 bond.

"Assumed values.

(7)

(8)

(9)

All distances/A

X

c13 C3 C0

0

I . I 59(2) A

N

'0

(10) X = H or CI

(1 1 )

The gas-phase molecular structures of CX(NO,), (X = H or Cl)87(10) and CH,CNBs (11) have been determined by electron-diffraction techniques. Structural parameters for CX(N02), are compared with recent data for CH,NO,, CH,Cl(NO,), and CCI,(NO,) in Table 2."' They are consistent with C3 models having similar parameters for r(C-N), r(N-0), and L O N 0 and different ones for LNCN (manifest in LHCN and LClCN). The C-Cl bond length for the tetrahedral carbon atom in CCl(NO,), (1.7 12 A) is the shortest yet found; thus, it varies within an interval of ca 0.1 A to a maximum of 1.828 in CClMe,." H4

E. G. Codding, R . A. Creswell, and R. H. Schwendeman, Inorg. Chem., 1974. 13, 856. E. G. Codding, C. E. Jones, and R. H . Schwendeman, Inorg. Chem., 1074, 13, 178. X 6 A. Guarnicri, L. Charpentier, and B. Kuck, Z. Naturforsch., 1973. 28a, 1721. H7 N. I. Sadova, N . I. Popik, L. V. Vilkov, Yu. A . Pankrushev, and V. A . Shlyapochnikov, J.C.S. Chem. Comm., 1973, 708. r(x K. Karakida, T. Fukuyama, and K. Kuchitsu, Bull. Chem. SOC. Japan, 1974, 47, 299.

'.'

Elements of Group IV Table 2 Structural parameters for selected nitro Parameters r (C-H)/A r(C-Cl)/A r (N-O)/A r (C-N)/A LHCNI" LClCNI" LONO/"

203

CH3N02" CH,CINO,b CC13N02' 1.088* 1.09Sd 1.765 1.726 1.224 1.230 1.190 1.489 1.493 1.594 Illd 107.2 114 106.0 125.3 128 131.7

CH(NOz), 1.13' 1.219(2) 1.505(5) 108h(0.6) -

128h(0.3)

CCI(NO,), 1.712(4) 1.213(1) 1.513(3) 112.1(0.5) 128.3(0.5)

a A. P. Cox and S. Waring, J.C.S. Faraday 11, 1972, 68, 1060; N. I. Sadova, L. V . Vilkov, and T. M. Anfimova, J. S t r u t . Chern., 1972, 13, 763; R. E. Knudsen, C. F. George, and J . Karle, J. Chem. Phys., 1966, 44, 2334; assumed values.

The crystal structures of C(CN),8' and AgC(CN),NO'' have been determined; C(CN),8' is trigonal with hexagonal axes, a = 9.062(2) and c = 11.625(3) A. The molecule has full tetrahedral symmetry, with average bond lengths r(C-C) = 1.481(3) 8, and r(C-N) = 1.147(5) A. One N atom points directly at the central C atom of an adjacent molecule, with N-C (in CN) distances of 3.05 A. The remaining three equivalent N atoms point approximately at central C atoms of three adjacent molecules, with N-C (in CN) distances of 3.00, 3.10, and 3.19 A. These short N-C distances are regarded as evidence of donor-acceptor interactions.8y The methanide AgC(CN),NO'* is orthorhombic, with lattice parameters a = 11.729, b = 10.299, and c = 7.868 A; the crystal packing is closely related to that of AgC(CN),. The structural parameters of the anion (12), which is almost planar, and its position relative to adjacent Ag atoms are shown in the diagram; each N and 0 atom bonds to an Ag atom to give roughly tetrahedral co-ordination at the Ag Ag -0.58 N -0.02

Ag'

-0.73

Bond distances/A and the distances/A of each atom out of mean anion plane

Bond angles/"

(a)

(b)

(12) 89 90

D. Britton, Acta Cryst., 1974, B30, 18 18. Y. M. Chow and D. Britton, Acta Cryst., 1974, B30, 1 1 17.

204

Inorganic Chemistry of the Main-group Elements

Table 3 Spectroscopic studies of methane and its substituted derivatives Spectroscopic technique Microwave 1.r

Molecules examined CD,F,;" CH,I;b CH,SCl;' CH,SCN;" CH,OPF,;' CH,PF,;f CF,CN;* CF,OF." CH,;' CH,D,;' CD,;k CH,F;' CXF, (X = H or D);" CF4;" CF,X ( X = CI, Br, or I);p CHCI,;" CH,Br;' CX,OH (X = H or D);" CX,OD (X = H or D);" CH,OH;' CHD,OH;" CD,OX (X = H or D);" CX,CN (X = H or D);" CH,DCN;" CH,NC;" CF,CN;' CH,DNX, ( X = H or D);' CF,NO;"" CX,ONO, (X= H or D)."'

Raman

CHJ;"' CH,OH;"" CH,NC;"' CHF,;"/ CF,NO;' CC14;a8CX, (X = C1, Br, or I).,'

V.V.

CF,,Cl,-,, ( I d n C 3);"' CHF,CI;"' CH,FCI;"' CHFCI,;'"

U.V.photoelectron

CH,OH;"' CH,SH;"' CX,SH (X = H or D);"* CH3NH2."'

N.m.r.

'H :CDCI,;"' 'H :CH,OH;"" I3Cl:CH,CN;"" 15N:CH,CN;"" 3 ~ 1CCI,."~ : CH,CN"¶

E.s.r. Electron-impact ionization Photoionization

CH,;-' CH,OH;"" CH,SH;"' CH3NHz."" CH,I;"" CH,Cl,-,, (0 C n =s3);"" CBr,.""

A. C. Nelson, S. G. Kukolich, and D. J. Ruben, J. Mol. Spectroscopy, 1974, 51, 107; Y . Kawashima and C. Hirose, Bull. Chem. SOC. Japan, 1973, 46, 2969; ref. 86; V. Andresen and H. Dreizler, 2. Naturforsch., 1974, 29a, 797; ref. 8 5 ; ref. 84; ref. 95; " ref. 92; ' L. A. Pugh, T. Owen, and K. N. Rao, J. Chem. Phys., 1974,60, 708; G. D. T . Tejwani and K. Fox, J. Chem. Phys., 1974, 60, 2021; G. Tarrago, M. Dang-Nhu and G. Poussigue, J. Mol. Spectroscopy, 1974, 49, 322; J.-C. Derouche, Compt. rend., 1973, 277, B, 611; * G. Poussigue, G. Tarrago, M. Dang-Nhu, and A. Valentin, J. Mol. Spectroscopy, 1974. 49, 183; J. Nakagawa, I. Suzuki, T. Shimanouchi, and T. Fujiyama, Bull. Chem. SOC. Japan, 1974, 47, 1134; 1973, 46, 3399; " P. Lockett and P. M . Wilt, J. Chem. Phys., 1974. 60, 3203; A. C. Jeanette, D. Legler, and J. Overend, Spectrochim. Acta, 1973, 29A, 1915; L. C . Hoskins and C. J. Lee, J. Chem. Phys., 1973, 59, 4932; K. H. Schmidt and A. Muller, J. Mol. Spectroscopy, 1974, 50, 115; J. Aubard and G. G. Dumas, Compt. rend., 1974, 278, B, 853; C . Betrencourt-Stirnemann, G. Graner, and G . Guelachvili, J. Mol. Spectroscopy, 1974, 51, 216; G . Graner, ibid., p. 238; A. Morita and S. Nagakura, J. Mol. Spectroscopy, 1974, 49, 401; * ref. 96; " ref. 97; D. C. McKean, Spectrochim. Acta, 1974, 30A, 1169; S. Kondo and W. B. Person, J. Mol. Spectroscopy, 1974,52, 287; D. C. McKean, Spectrochim. Acta, 1974, 30A, 116Y; M. Godon and A. Bauer, Compt. rend., 1974, 278, B, 113; S. J. Daunt and H. F. Shurvell, J. Chem. Phys., 1974, 60, 2199; ' ref. 98; an ref. 93; ab J. A. Lannon, L. E. Harris, F. D. Verderame, W. G . Thomas, E. A. Lucia, and S. Koniers, J. Mol. Spectroscopy, 1974, 50, 68; ref. 102; ad W. F. Murphy, A . S. Gilbert, H. J. Bernstein, and R. M . Lees, J. Mol. Spectroscopy, 1974, 51, 394; ae J. E. Davies and W. J. Wood, J. R a m a n Spectroscopy, 1973, 1, 383; af W. Holzer, Chem. Phys. Letters, 1973, 22, 375; ref. 101; ah R. J. H. Clark 'and P. D. Mitchell, J. Mol. Spectroscopy, 1974, 51, 458; a' R. Gilbert, P. Sauvageau, and C. Sandorfy, J. Chem. Phys., 1974,60,4820; "1 H. Ogata, H. Onizuka, Y . Nihei, and H. Kamada, Bull. Chem. Soc. Japan, 1973, 46, 3036; B . - 0 . Jonston and J. Lind, J.C.S. Faraday 11, 1974, 70, 1399; "' ref. 100; ref. 91; an S. Kaplan, A. Pines, R. G . Griffin, and J. S. Waugh, Chem. Phys. Letters, 1974, 25, 78; ap ref. 99; ref. 103; G. R. Wight and C. E. Brion, J. Electron Spectroscopy, 1974, 4, 25; ref. 104; G. R. Wight and C. E. Brion, J. Electron Spectroscopy, 1974, 4, 25; M. Toyoda, T. Ogawa, and N. Ishibashi, Bull. Chem. Soc. Japan, 1974, 47, 95; B. P. Tsai and T. Baer, J. Chem. Phys., 1974, 61, 2047; ref. 105. a

"

'

'

(Irn

Or

Elements of Group IV 205 The H-C-H bond angle in CH,OH has been determined to be 109”21’*4’ from an analysis of the ‘H n.m.r. spectra of CH,OH in a nematic liquid-crystal solvent using a pulsed R.T. n.m.r. ~ p e c t r o m e t e r . ~ ~ Spectroscopic Studies. A large number of papers have been published which describe the spectroscopic properties of methane and its substituted derivatives; the molecules examined using each technique (i.r., Raman, u.v., n.m.r., etc.) are listed in Table 3. Structural information has been obtained from both m i c r o w a ~ e ~and ~ - ~n.m.r. ~ data.91 Barriers to internal rotation have been calculated from both m i c r o w a ~ e ~and ~ * ~i.r.~ * ~ ~ the results are collected and compared with a theoretically derived value for CH,0H9*in Table 4. The dipole moments of CH,PF,84 (2.056* 0.006 D) and CF3CNg5(1.262f0.010 D) have also been derived from analyses of microwave spectra.

Table 4 Barriers to internal rotationlcal mol-1 for a number of substituted methanes CH,0HY4 1440

CH,PFzB4 2300*50

CH,OPF,”’ CD3OPFZs5 422k5 404k5

CF30F9’ 3900

CF3NO” 425

Rotational isomerism in methan01,~~deuteriated methan01,”~~’ and deuteriated methylamineg8has been studied using i.r. spectroscopic techniques. Sarrallach et aLg6have concluded that there is experimental evidence indicating that the staggered rather than the eclipsed conformation is favoured for gaseous and matrix-isolated CH,OH. In an independent analysis, Mallinson and McKean9’ have suggested that the two stretching frequencies in the i.r. spectra of gaseous and matrix-isolated CHD,OH (Table 5 ) reveal the presence of two C-H bonds. The higher frequency, which corresponds to a shorter bond length, has been assigned to the sym-species (13a), whereas the lower frequency has been assigned as the asym-species (13b).97Similarly, the gas-phase i.r. spectra of CH,DNH2 and CH2DND2have been interpretedg8as a combination of the spectra of the trans -(14a) and gauche -( 14b) rotational isomers. Table 5 1.r. spectral data for CHD,OH” v(C--H)gas

phae

Icm-’ 2978.7 2919.3 91

92

” 94 95

v (C--H)mamx-Lsolated Icm-’ 2986.4 2931.0

Bopd length/A 1.094 1.100

Assignment

sym -species asym-species

P. K. Bhattacharyya and B. P. Dailey, J. Chem. Phys., 1973, 59, 3737. P. Buckley and J. P. Weber, Canad. J . Chem., 1974, 52, 942. H. F. Shurvell, S. C. Dass, and R. D . Gordon, Canad. J. Chem., 1974, 52, 3149. L. M . Tel, S. Wolfe, and I. G. Csizrnadia, J. Chem. Phys., 1973, 59, 4047. P. B. Foreman, K. R. Chien, J. R. Williams, and S. G. Kukolich, J . Mol. Spectroscopy, 1974,

52, 25 1. A. Serrallach, R. Meyer, and H. H. Giinthard, J. Mol. Spectroscopy, 1974, 52, 94. ’’ P. D . Mallinson and D . C . McKean, Spectrochim. Acta, 1974, 30A, 1133. 98 K. Tarnagake and M. Tsuboi, Bull. Chem. SOC. Japan, 1974, 47, 73. 96

206

Inorganic Chemistry of the Main-group Elements

D*D

H

H*D

(b) D

(4

The molecular rotation in liquid and solid CC1499and liquid CDCl,'" has been estimated from measurements of spin-spin relaxation times of 35Clin CC1, (250-556 K) and of 'H in CDCl, (301-438 K). Independent Raman studies of the reorientation of CCl,'"' and CH,I'O2 in the liquid phase have also been undertaken. The configuration and reactivity of methyl radical-cyanide ion pairs produced by dissociative electron capture in the two solid phases of CH,CN have been studied by e.s.r. techniques using CD,13CN.'03The results indicate that the radical configuration is planar and that the reactivity of the radical (as estimated from hydrogen-abstraction rates) in crystal I is at least 10 times greater than in crystal 11. Binding energies and momentum distributions for electrons in the valence orbitals of CH, have been presented;lo4 these are the first data obtained by the (e, 2e) reaction (electron-impact ionization with complete determination of the kinematics of the incident and emitted electrons) for a polyatomic molecule. The vertical I.P.'s obtained for the It, and 2a, electrons of CH, are compared with values from U.P.S.and photoionization studies in Table 6; the data derived from the three techniques are in satisfactory agreement. In a photoionization study of the I.P. and fragment appearance potentiah of CH,Clr-, (0 S n 3) and CBr4, it has been observed that although CBr; is stable, CCl: is unstable.'" In the energy range studied, fragmentation of the molecules was found to be limited to halogen loss. The experimental data

'' D. E. O'Reilly, 'On lo'

"'2

1"3 '04

E. M. Peterson, and C. E. Scheie, J. Chem. Phys., 1974, 60, 1603. D. L. Vanderhart, J. Chem. Phys., 1974, 60, 1858. S. Sundar and R. E. D. McClung, Chem. Physics, 1973, 2, 467. R. Gilbert, P. Sauvageau, and C. Sandorfy, J. Chem. Phys., 1974, 60, 4820. E. D. Sprague, K. Takeda, J. T. Wang, and F. Williams, Canad. J. Chem., 1974, 52,2840. S. T. Hood, E. Weigold, I. E. McCarthy, and P. J. 0. Teubner, Nature Phys. Sci., 1973, 245, 65.

Elements of Group IV 207 Table 6 Vertical I.P./eV for the It, and 2a, electrons of CH, Technique: Electron-impact U.P.S.b U.P.S.' Photoionization" ionization" Vertical LP. lt,: Vertical I.P. 2a1:

13.8k0.15 23.1 *0.10

14.35 22.9

13.6 23.1

13.77 -

ref. 104; K. Hamrin, G. Johanssohn, U. Gelius, A. Sahlman, C. Nordling, and K. Siegbahn, Chem. Phys. Letters, 1968, 1, 613; ' A . W. Potts and W. C. Price, Proc. Roy. SOC., 1972, A326, 165; * R. Stockbauer and M. G. Inghram, J. Chern. Phys., 1971, 54, 2242.

a

are in excellent agreement with U.P.S.data, where values for the latter exist (Table 7); electron-impact appearance potentials, however, are generally higher than those determined by U.P.S. or photoioni~ation.'~~

Table 7 I.P/eV and fragment appearance potentialslev for CH, CL-, (0 G n 3) and CBT,'~' System: CH3CI-CH3CI' CH2Cl2-CH2Cl; CHC1,-CHCI; Photo ion ization data: 11.28ztO.01 11.32k0.01 11.37zt0.02 U.P.S.data: 11.29 11.31 11.48 System: Photoionization data:

CH2CI,-CH,Cl'

CHCl,-CHCl;

12.12zt0.02

11.49zt0.02

CBr,-CBr: 10.31k0.02 -

CBr,-CBr; 10.47k0.02

CCl,-CCl; 11.28~t0.03

Chemical Studies. A reportlM showing that chlorofluoromethanes are being added to the environment in steadily increasing amounts has been published. These compounds are chemically inert and may remain in the atmosphere for 40-150 years, and concentrations can be expected to reach 10 to 30 times the present levels. Photodissociation of these molecules in CFCl,

--+ CFCl,

+ C1

(8)

CF,Cl, + CF,Cl+ C1 (9) the atmosphere [reactions (8) and (9)] produces significant quantities of C1 atoms and leads to the destruction of atmospheric ozone and oxygen atoms [reactions (10) and (1 1)].lo6 c1+03-+c10+02 (10) c10+0-+c1+0,

(1 1)

A mode11°7 has been established to explain the isotopic fractionations of natural methane as a function of the thermocatalytic development of the source material. Thus methane gases characterized by low isotopic ratio values ( i e . enriched in "C) can be traced back to young organic material only affected by relatively low temperatures, whereas high I3C concentrations show that the gas originated during either coal-formation processes or thermal-destruction processes at high temperature.lo7 'OS

'07

A. S. Werner, B. P. Tsai, and T. Baer, .I. Chem. Phys., 1974, 60, 3650. M. J . Molina and F. S. Rowland, Nature, 1974, 249, 810. W. Stahl, Nature, 1974, 251, 134.

208

Inorganic Chemistry of the Main -group Elements

A considerable proportion of the chemistry of the substituted methanes described during the period of this Report involves their reaction with and ions (e.g. H', atoms (e.g. K, F, and 0),diatomic molecules (Br2?02,H2), NO', CH:). The systems studied are summarized in Table 8. The oxidation of both CH410s110 and CH,OH"'."* has been investigated using a number of techniques. The effect of the discharge unit wall

Table 8 Reactions of methane and its substituted derivatives with atoms, molecules, and ions that have been studied recently Li + CH,X (X = Br or I)" Na+CH,X (X=Br or I)" K + CH,Br" K + CH31a-d K+CF,I' Rb + CHJ' Cs + CF,X(X = Cl, Br, or I)" H+CH; F + CH,'.' F+CH,D,k F + CHF,' F+CH,CI,+, ( l S n ~ 3 ) ' F +CH2Cl,' F + CH,X (X = F, C1, Br, I, or OD)' F -tCF,Brl Br + CH," O+CH,Cl,-, (n = 4 , 3, 1, or 0)" 0 + CH, C14-,, (1G n 43)p 0 + CH,Br,P

0 + CF3Brq S + CHI' N + CH3OH" T + CH, (T = hot atom)' T + CD, (T = hot atom)' Br2+CH,F4-, (n = 2 or 3)" Br, + CC14" 0, +-CH4W'x 0, + CH30HY.' H, + CH4" H' + CH,OH"" NO*+ CH30Hab CH4D++ CH4aC CH: + CHqad CH,' + CH," CD; + CDqPd CD:+CD,ad."' CD;+CH,X (X= F,CI, Br, or I)"'

" A. M. C. Moutinho, J. A. Aten, and J. Los, Chem. Physics, 1974, 5, 84; R. E. Roberts and C. I. Nelson, Chem. Phys. Letters, 1974, 25, 278; B. C. Eu, J. Chem. Phys., 1974, 60, 1178; R. A. LaBudde, P. J. Kuntz, R. B. Bernstein, and R. D. Levine, J. Chem. Phys., 1973, 59, 6286; A. M. Rulis, B. E. Wilcomb, and R. B. Bernstein, J. Chem. Phys., 1974, 60, 2822; H. E. Litvak, A. Gonzalez Ureiia, and R. B. Bernstein, J. Chem. Phys., 1974, 61, 738; E. W. Rothe, S. Y. Tang, and G. P. Rock, Chem. Phys. Letters, 1974, 26, 434; J. C. Biordi, J. F. Papp, and C. P. Lazzara, J. Chem. Phys., 1974, 61, 741; ' R. L. Johnson, K. C. Kim, and D. W. Setzer, J. Phys. Chern., 1973, 77, 2499; M. A. A. Clyne, D. J. McKenney, and R. F. Walker, Canad. J. Chem., 1973, 51, 3.596; ' A. Persky, J. Chem. Phys., 1974, 60, 49; I J. W. Bozzelli, C. E. Kolb, and M. Kaufman, J. Chem. Phys., 1973, 59, 3669; R. W. Helton, D. W. Oates, and E. P. Rack, Bull. Chem. SOC.Japan, 1973, 46, 2877; J. Barassin and J. Combourneu, Bull. SOC.chim. France, 1974, 1 ; S. J. Arnold, G. H. Kimbell, and D. R. Snelling, Canad. J. Chem., 1974, 52, 271; T. C. Frankiewicz, F. W. Williams, and R. G. Gann, J. Chem. Phys,, 1974, 61, 402; ' A. DrSgSnescu, I. Bic5, C. Peterescu, A. M. Pavlovschi, S. Serban, and N. Merjanov, Reu. Roumaine Chim., 1973, 18, 1859; J. M. Roscoe and S. G. Roscoe, Canad. J. Chern., 1973, 51, 3671; L. M. Raff, J . Chem. Phys., 1974. 60, 2220; ref. 1 13; ref. 114; ref. 109; ref. 110; ref. 11 1 ; ref. 112; "" ref. 115; ob ref. 116; R. C. Pierce and L. F. Porter, J. Phys. Chem., 1974, 78, 93; ad W. T. Huntress and R. F. Pinizzotto, J. Chem. Phys.. 1973. 59, 4742; .I.H. Futrell, J. Chem. Phys., 1973, 59, 4061; J . M. S. Henis, M. D. Loberg, and M. J. Welch, J. Amer. Chem. Soc., 1974, 96, 1665. Of

I

ox

I09 I 1 0 Ill

11-2

V. B. Luk'yanov. E. F. Simonov, and A. M. Mozhaiskii, Russ. J. Phys. Chem., 1973, 47, 1591. St. Antonik, Bull. SOC. chim. France, 1973, 3296. V. Borie, Cornpt. rend., 1974, 278, B, 815. A. C . Herd, T. Onishi, and K. Tamaru, Bull. Chem. SOC.Japan, 1974, 47, 575. L. N. Kurina, N. V. Vorontsova. and V. P. Morozov, Russ. J. Phys. Chern., 1973,47, 1230.

Elements of Group IV

209

temperature on the rate of formation of the products in the CH4-CO, dischargelo8has been studied, as has the effect of chlorine on the products (CH,OH, H2C0, and H,O,) of the oxidation of CH4.lo9In the presence of increasing amounts of chlorine, a progressive disappearance of CH30H and H 2 0 2was observed, the formation of H,CO passing through a maximum at ca. 0.2% C1,.'09 The experimental results obtained for the limits of inflammability of the CH4-H2-air system at room temperature have been interpreted successfully in terms of a radical chain reaction.ll0 The catalytic oxidation of CH30H using both zinc oxide"' and supported silver112 has been examined in order to ascertain the reaction mechanism,"' the effect of CH,OH:O, ratio,'12 and the role of impurity water in the reaction.'" The bond-dissociation energies, D(CHF,-Br) = 289 f 8 kJ mol-',"' ,'~~ the enthalpies of formation, D(CC1,-Cl) = 294.6 f4.2 kJ m ~ l - ~ and A@(CHF,Br,g) = -425.3 f0.9 kJ mol-l,ll3 AHe (CCl,,g) = -93.7k 1.7 kJ m ~ l - ' , "have ~ been determined from studies of the equilibria (12) and (13). Br, + CH,F,

$ HBr

+ CHF,Br

(12)

Br, + CCl, BrCl + CC1,Br (13) The enthalpy of formation of CC14, which is necessarily based on that of CHC13,is higher than obtained in many earlier Reaction (14) has Br, + CH,F

== HBr + CH,FBr

(14)

also been studied, but true equilibrium was not attained, owing to the unexpected formation of CH,Br as a major p r ~ d u c t . " ~ Two investigations of the clustering of methanol molecules around simple cations, Hf115and N0+,'l6have been undertaken in the rapidly advancing field of ion-cluster compounds. The equilibria (15) have been studied as a H+(CH,OH),

H'(CH,OH),-, +CH,OH

(2 =sn S 8)

(15)

function of temperature to evaluate AHZ,n-l, AGZ.n-l, and AS&l."5 The results have been compared with similar determinations for H+(H20), and H+(Me20),.In an independent investigation,l16 NO+ was found to undergo consecutive clustering reactions with CH,OH until four molecules had been added. These reactions, studied mass-spectrometrically, were found to be in competition with a series of other reactions producing the solvated proton and, presumably, methyl nitrate.l16 Mass-spectroscopic studies of CX,SH (X = H or D),'" CF,NO,"' and the CH, radical''' (produced by photolysis of CH,I) have been undertaken. 'I'

'I4 'Is 'I6 I"

'I8 'I9

E. N. Okafo and E. Whittle, J.C.S. Faraday I , 1974, 70, 1366. G. D. Mendenhall, D. M. Golden, and S. W. Benson, J. Phys. Chern., 1973, 77, 2707 E. P. Grimsrud and P. Kebarle, J. Arner. Chern. SOC., 1973, 95, 7939. D. L. Turner and L. I. Bone, J. Phys. Chem., 1974, 78, 501. B.-0. Jonsson and J. Lind, J.C.S. Faraday 11, 1974, 70, 1399. B. G. Syruatka and M. M. Gil'burd, Russ. J. Phys. Chern., 1973, 47, 1215. S. Yamashita, Bull. Chem. SOC. Japan, 1974, 47, 1373.

210

Inorganic Chemistry of the Main-group Elements Gas-phase cation chemistry of CH,F4-, (0 =sn s 3) has been investigated using ion-cyclotron resonance spectroscopy;1Zo the observed stability of the fluoromethyl cations decreases in the sequence: CHF: > CH2F+> CF; > CH;

The production of negative ions from CH,X (X = Br, I, CN, or NO,) by both thermal electron attachment and electron capture from excited atoms has also been studied.I2' Hydrolysis of CF,C14-, (0 S n d 4) has been investigated in the temperature range 30-500 "C and pressure range 10-4000 atm.LZZ No reaction was observed with CF, or CF,C1. Although CCl, undergoes simple hydrolysis (16), that of CFC1, and CF2C12is thought to occur v i a randomization (17) and subsequent hydrolysis of CC1, (16). The denitration of CH3N02, CCl, 3CF,Cl,

-+

+ 2H,O

-+

CO, + 4HC1

CC1, + 2CF3Cl; 2CFC1,

-+

CCl, + CF,Cl,

(16) ( 17)

induced by hydroxyl radical, has been examined by Eiben."' Addition of the radical (produced by irradiation of the solution) to a c i -nitromethane, CH,=NO;, the predominant form of nitromethane above p H = 10, leads to the transient anion of hydroxynitromethane, HOCH,NO,, as shown in reaction (1S), which decays via disproportionation (19). The oxidized CH3N02 2HOCH,NO,

CH,=NO; OH-\HOCH,NO,

e HOCH,NO, + HOCH,NO:-

(18)

(19)

product HOCH,NO, decomposes to yield nitrous acid and formaldehyde (20); the reduced product probably protonates and eliminates H 2 0 to form HOCH2N0,-+ H,CO + HNO, HOCH2NO:-

-:: HOCH2N0 >

(20) (21)

hydroxynitrosomethane as shown in reaction (2l).123 Thermal decomposition af both CH41242125 and CC1,NO'26 has been investigated under differing conditions. Although NO, CCl,, CCl,N=CCl,, CCl,NO,, NOCl, and COC1, were identified as products of the CC1,NO pyrolysis, the previously reported product, CCl,N(O)=CCl,, was not positively identified.lZ6 ''(I 121

lZ3

R. J. Blint, T. B. McMahon, and J . L. Beauchamp, J. Amer. Chem. SOC.. 1074, 96, 1260. J. A. Stockdale, F. J. Davis, R. N. Compton, and C . E. Klots, J . Chern. Phys., I Y 7 4 . 60, 427Y. A. P. Hagen and E. A. Elphingstone, J. Inorg. Nuclear Chem., 1974, 36, 509. K. Eiben, Z . Naturforsch., 1974, 29b, 562. K . I. Makarov and V. K. Pechik, Carbon, 1974, 12, 391. G. A. Vompe, Russ. J. Phys. Chem., 1973, 47, 788. B. W. Tattershall, J.C.S. Dalton, 1974, 448.

Elements of Group IV

211

The production of hydrocarbons from CH,OH was achieved for the first time when it was heated (< 190 "C) in phosphorus pentoxide, polyphosphoric acid, or combinations thereof About 200 hydrocarbons were obtained in ca. 36-39% yield. The discovery is remarkable because CH30H does not form an alkene and yet must proceed from a one-carbon compound to multi-carbon units. Two interpretations of the reaction mechanism, based on either the five-co-ordinate carbon atom of Olah or carbene as intermediates, have been proposed.lZ7 The primary products found in the radiolysis of liquid CH,0H'28s'29and of aqueous solutions of CH3CN,I3' CHC13,131and Cc1,"' have been examined. Those observed in liquid CH30H are the CH30' and 'CH,OH radical^.^^^*^^^ Although 'CCl, radicals are found in the radiolysis of both CHCl, and CC1, solutions, 'CHC1, radicals are also believed to be formed in the former solutions .I3' Trifluoromethyl peroxynitrate, CF,OONO,, has been obtained in high yield by the reaction of CF,OOH with N,O, or C F 3 0 0 F with N,04."' Its CF3OOH + N205

--j,

CF3OON02 + HNO,

(22)

physical and chemical properties are reported together with an assignment, based on C3 symmetry, of its vibrational spectra.13' Reaction (24) has been CHC1, + F2S03+ CHCl,OSO,F

+ ClF

(24)

st~died.',~Although ClF is quoted as a reaction product, it was not positively detected, presumably because of reaction with the glass reactor exit. A small amount of CC1,F was also obtained as a b y - p r ~ d u c t . ' ~ ~ Several papers have been published describing donor-acceptor interactions in systems involving both CH,"" and its substituted d e r i ~ a t i v e s . ~ ~ ~ - ~ ~

I*'

Izy "" 13'

13'

'31 13* 139

''" 14' '41

143

D. E. Pearson, J.C.S. Chem. Comm., 1974, 397. F. P. Sargent, E. M. Cardy, and H. R . Falle, Chem. Phys. Letters, 1974, 24, 120. S. W. Mao and L. Kevan, Chem. Phys. Letters, 1974, 24, 505. I. Dragonit, Z . Dragonit, Lj. Petkovit, and A. Nikolit, J. Amer. Chem. SOC., 1973, 95, 7193. B. Lesigne, L. Gilles, and R. J . Woods, Canad. J. Chem., 1974, 52, 1135. F. A. Hohorst and D. D . DesMarteau, Inorg. Chem., 1974, 13, 715. L. F. Cafferata and J. E. Sicre, Inorg. Chem., 1974, 13, 242. V. A . Koroshilov and E. B. Bukhgalter, Russ. J. Phys. Chem., 1973, 47, 1348. R. T. Yang and M. J . D. Low, Spectrochim. Acta, 1974, 30A, 1787. G . R. Choppin and J. R . Downey, Spectrochim. Acta, 1974, 30A, 43. M. A. Hussein and D. J. Millen, J.C.S. Faraday Ir, 1974, 70, 685. D.J . Millen and G. W. Mines, J.C.S. Faraday 11, 1974, 70, 693. N. F. Cheetham, I . J. McNaught, and A. D. E. Pullin, Austral. J. Chem., 1974, 27, 973. N . F. Cheetham, I. J. McNaught, and A. D. E. Pullin, Austral. J. Chem., 1974, 27, 987. I. J . McNaught and A. D. E. Pullin, Austral. J. Chem., 1974, 27, 1009. V. P. Anferov, V. S. Grechishkin, and M. Z . Yusupov, Russ. J. Phys. Chem., 1973,47,713. H . Langer, H . C. Hertz, and M. D . Zeidler, Chem. Phys. Letters, 1973, 23, 417. T. N . Naumova, T. S. Vvedenskaya, L. S. Zhevnina, and B. D . Stepin, Russ. J. Phys. Chem., 1973, 47, 1257.

212

Inorganic Chemistry of the Main-group Elements

Evidence for these interactions is usually obtained from analyses of spectroscopic data. Thus, interactions between CH4,13,CH30H,I3' CHC13,136 and H 2 0 have been verified. Donor-acceptor complexes between CH30H,'37s'38 ~ ~ ~ ~ ~ , 1 3~~~1,139-141 9.140 and a number of amines have been studied; the stability of the donor-acceptor bond has been found to increase with increasing substitution of the amine.'37.'38Interactions between CHCl, and a number of organic molecules, including CH,CN and (CH3CO>,O,"' between CCl, and C2HsOH,143 and between CCl, and SO,Cl,'"" have also been investigated to elucidate the interaction mechanisms. Formaldehyde and its Substituted Derivatives.-Formaldehyde, Carbonyl Halides, etc. Despite the general decrease in the number of publications in this field, the high proportion describing the spectroscopic properties of these molecules has been maintained; these, together with the corresponding publications for formic acid and formates, are collected in Table 9. The

Table 9 Spectroscopic studies of formaldehyde and its substituted derivatives Spectroscopic technique Microwave 1.r.

Raman U.V. Photoelectron

Molecules examined HCO;" F,CO;b F,CS;' H(NH,)CO;d H(NH,)CS.' H,CO;'." D,CO;"." CI(CX,O)CO ( X = H or D);' HC0,H;' DC0,D;' y-Ca(HCOO),;k p - and S-Sr(HCOO),.k H,CO;'.' HDCO;' D,CO;' CI(CX,O)CO ( X = H or D);' Ca(HC00)2.m D,CO;" CI,CS;p HCO,H.q H,CO (X.P.S.);' X(F,CS)CS (X = F, C1, or SCF,) (U.P.S.)'

ref. 149; ref. 145; ref. 146; ref. 147; ref. 148; A . Khoshkoo, S. J. Hemple, and E. C. Nixon, Spectrochim. Acta, 1974, 30A, 863; J. W. C. Johns and A. R. W. McKellar, J. Mol. Spectroscopy, 1973, 48, 354; S. Tatematsu, T. Nagakawa, K. Kuchitsu, and J. Overend, Spectrochirn. Acta, 1974, 30A, 1585; ' J . E. Katon and M. G. Griffin, J. Chem. Phys., 1973, 59, 5868; H, R. Zelsman and Y. MarCchal, Chem. Physics, 1974, 5, 367; li B. F. Mentzen and C. Comel, Spectrochim. Acta, 1974, 30A, 1263; ' A. Chapput, B. Roussel, and G. Fleury, J . Rarnan Spectroscopy, 1973, 1, 507; R. S. Krishnan and P. S . Ramanujam, J. Rarnan Spectroscopy. 1973, 1, 533; B. J. Orr, Spectrochim. Acia, 1974. 30A, 1275; D. C. Moule and C. R. Subramanian, J. Mol. Spectroscopy, 1973, 48, 336; T. L. Ng and S. Bell, J. Mol. Spectroscopy, 1974, 50, 166; ' T. X. Carroll and T. D. Thomas, J. Electron Spectroscopy, 1974, 4, 270; ' H. Bock, K. Wittel, and A. Haas, Z . anorg. Chem., 1974, 408, 107.

a

molecular geometries of F 2 C 0 (15),14' F,CS (16),'46H(NH,)CO (17),'"' H(NH,)CS (18),14' and the HCO radical have been determined from their microwave spectra. The effect of substituting S for 0 in both F,CO and H(NH2)C0 is minimal since the C-F and N-C bond distances and the LFCF and LXCN ( X = O or S) in the comparable molecules are in agreement within experimental error. The dipole moment of F2CS, which at was prepared by pyrolysis of tetrafluoro-1 ,3-dithietan, S-CF,-S-CF,, I

'41

I47 '41

I

J. H. Carpenter, J . Mol. Spectroscopy, 1974, 50, l X 2 .

A. J. Careless, H. W. Kroto, and B. M. Landsberg, Chem. Physics, 1973, 1, 371. E. Hirota, R. Sugisaki, C. J. Nielsen, and G. 0. Sorensen, J. Mol. Spectroscopy, 1974, 49, 25 I . R. Sugisaki, T. Tanaka, and E. Hirota, J. Mol. Spectroscopy, 1974, 49, 241.

213

Elements of Group IV F \1.3

F

\ 1.3lS(lO)

166(10)

0

F' (1 5)

(17)

(18)

All distances/A.

500 "C in a quartz tube, has been calculated to be 0.080 D.'"" The geometry is compared with experimentally and theoretically of the HCO derived geometries of H2CO"' in Table 10; the major changes observed in the experimental data on formation of the radical are an increase in LHCO and a slight decrease in r(C-0). The calculated bond lengths of H,CO are shorter than those determined experimentally; the deviation is consistent Table 10 Molecular geometries of HCO and H 2 C 0 HCOI~~

H,CO (theor.)'" H,CO ( e ~ p t . ) ' ~ '

r(C-O)/A 1.17 1.1781 1.203

r(C-H)/A 1.11 1.0924 1.101

LHCO 127" 122'3' 121'44'

with the general observation that Martree-Fock calculated bond lengths are usually shorter than experimental values, whereas Hartree-Fock calculated bond angles are very a~curate.'~' Three other theoretical investigations of H 2 C 0 have been e f f e ~ t e d ; l ~ ' the - l ~ ~data obtained are compared with those for D,CO"' and H,CS."' Two independent theoretical analyses of the hydrogen bond in H2CO-H20 dimers have also been ~ n d e r t a k e n , ~ ~ ~ . ~ ' ~ The kinetics of the oxidation of formaldehyde have been determined in two separate s t ~ d i e s . l ~Data ~ , l obtained ~~ using the newly discovered Mo-0-S catalysts indicate that the catalyst dissociates the H2C0 [equation ( 2 5 ) ] HZCO + CO + H2

(25)

J. A. Austin, D. H. Levy, C. A. Gottlieb, and H. E. Radford, J . Chem. Phys., 1974,60, 207. W. Meyer and P. Pulay, Theor Chim. Acta, 1974, 32, 2.53. I T ' E. S. Yeung and C . B. Moore, J. Chem. Phys., 1974, 60, 2139. Is' P. J. Rruna, S. D. Peyerimhoff, R. J . Bucnker. and P. Rosmus, Chem. Phystcs, 1974,3,35. ' 5 3 J . L. Duncan and P. D. Mallinson, Chem. Phys Letters, 1973, 23, 597. J. E. Del Bene, Chem. Phys. Letters, 1973, 23, 287. Is5 W. R . Wolfe and K. B. Keating, J. Electrochem. SOC., 1974, 121, 1125. '" A. K. Wadhawan, P. S. Sankhla, and R. N. Mehrotra, Indian J. Chem., 1973, 11, 567. '49 15"

Inorganic Chemistry of the Main -group Elements

214

with subsequent oxidation of the CO and HZso formed.155The mechanism [reactions (26)-(30)] of the oxidation of H,CO by Ce" in aqueous NO; CelV

H*O

L CeOH'++H+

CelV+ NO,

H

\

/O'

+ Ce'"

[Ce(N03)]"

___f

HC0,H

+ Ce'" + H'

(26) (27)

(30)

H

has been formulated, with reaction (29) as the rate-determining step. The reaction of H,CO with active oxygen gives rise to a chemiluminescence which has been attributed to the electronic transitions of HO, radicals produced in reaction (31)."' The kinetics of the oxidation of formyl radicals by oxygen atoms [reaction (32)] have also been s t ~ d i e d . ' ~ '

CHO +o:+.HO:

+ co

CO+OH +- CHO+O --$ CO,+H

( 3 1)

(32)

Thermal decomposition of H,CO in the presence of NO has been studied at 500°C.159The results indicate that the pyrolysis is initiated by reaction (33) and involves the chain-carrying step (34).

NO + H,CO

-+HNO

+ CHO

2 H N 0 +. N, + 2 0 H

(33)

(34)

18F exchange between F,CO and Group I fluorides (LiF-CsF) has been studied to ascertain the effect of dipolar aprotic Exchange varies in the order Cs> Rb >> K > Na, Li at 423 K (Cs > Rb >> K, Na, Li at 323 K), and is enhanced in the presence of acetonitrile or diglyme but not benzene or ether. 'sI

K. H. Becker, E. H. Fink, P. L*angen, and U. Schurath, Z . Naturforsch., 1Y73, 28a, 1872.

N.Washida, R. I. Martinez, and K. D. Bayes, 2. Nahtrforsch., 1974, 29a, 251. "" ""

K. Tadasa, N. Imai, and T. Inaba, Bull. Chem. SOC. Japan, 1974, 47, 548. C . J . W. Fraser, D. W. A . Sharp, G. Webb, and J. M . Winfield, J.C.S. Dalton, 1074, 112.

Elements of Group IV 215 Formic Acid and Formutes. A theoretical and experimental ('H n.m.r.) investigation of ionic solvation in HCO,H has been undertaken.161 Calculations for the C1O;-HC0,H system indicate small solution energies, very small changes in molecular geometries as a result of solvation, and higher solvation numbers for C10; than for monatomic ions. These conclusions have been verified by the experimental data.16' Analysis of the results obtained in the photoionization of HCOzH has led to a value of AH*(HCO,g) = 10.2 kcal mol-' 16' (cf. 9.9 kcal mol-' derived from the photoionization of H2CO). A kinetic study of the reaction of formate and peroxydisulphate in aqueous solution [reaction (35)] has been made.163A mechanism has been proposed based on a chain reaction involving SO:, OH; and CO; radicals. S,O:-+HCOO- + 2SOi-+H++CO,

(35)

The crystal structures of potassium d i t h i ~ f o r m a t e 'and ~ ~ ammonium carbamatei6' have been determined; K(HCS,) is tetragonal (a = 10.596, c = 7.946 A), NH,C0,NH2 is orthorhombic, (a = 17.121, b = 6.531, c = 6.842A). The carbamate ion is planar; the bond angles and distances (corrected for thermal libration) are shown in diagram (19).'"

(a) Bond distances/A

(b) Bond angles

(19)

Derivatives of Group VI Elements.-Oxides, Sulphides, and Related Species. With the exception of the oxidation of CO, surprisingly little interest has been shown in the inorganic chemistry of these molecules during the period of this Report; as a result of this paucity of data, the molecules will not be considered individually, as in previous Reports. Theoretical calculations of the electronic structures of the unstable intercarbon suboxide C302,167.'68 and carbon monoxide dimer mediate C20,166 C20,'69 have been carried out. It has been concluded that C20, can be bound (with respect to two CO molecules) and will exist as a ground-state 16' lh2

163 164

166

I67 168 169

B. M. Rode, Monatsh., 1974, 105, 308. P. Warneck, Z . Naturforsch., 1974, 29a, 350. M. Kimura, Inorg. Chem., 1974, 13, 841. R. Engler, G. Kiel, and G. Gattow, 2. anorg. Chem., 1974, 404, 71. J. M. A d a m and R. W. Small, Acta Cryst., 1973, B29, 2317. C. Thomson and B. J. Wishart. Theor. Chim. Acta, 1973, 31, 347. H. H. Jensen, E. W. Nilssen, and H. M. Seip, Chem. Phys. Letters, 1974, 27, 338. R. D. Bardo and K. Ruedenberg, J. Chem. Phys., 1974, 60, 932. N . H. F. Beebe and J. R. Sabin, Chem. Phys. Letters, 1974, 24, 389.

216

Inorganic Chemistry of the Main-group Elements triplet (3Z).1"9The state formed from two ground-state C O molecules is repulsive, however, and, in order to produce C,O, in a bound state, it will be necessary t o use one. excited C O Lipscomb"" has recently commented on a previous assignment of the crystal structure of a -CO. Krupskii et al."' assigned a disordered structure in the space group P a 3 , the space group P2,3 (of lower symmetry) being rejected on the basis that it is in conflict with the disorder required by the residual entropy. Lipscomb refutes the rejection of the P2,3 space group, stating that no contradiction need exist between the residual entropy and the choice of this space group. H e suggests that more accurate measurements are required o n the structures of a-CO and the isoelectronic a - N , before definite conclusions can be drawn.17" A number of investigations of the spectroscopic properties of these molecules have been described. The i.r. spectra of C0,172.173 C02,"4 and CS,'75have been investigated; the CO bond length, force constant, and i.r. band intensity of CO in the presence of strong electric fields have been analysed the~retically."~ The results have been applied to the interpretation of the i.r. spectra of weakly adsorbed CO on various surfaces and of CO in transition-metal carbonyl complexes. The U.V.spectra of free CO,"" CO chemisorbed o n MgO of high surface area,177 and C02"6 have been measured. The spectra of the chemisorbed species177are consistent with electron transfer and the development of conjugated adsorbed aromatic oxo car bon mions such as the (C0):- (4 d n =s6) species (20)-(22) o r open

conjugated structures such as (23). The U.P.S. of C0,179,180 C02,179COSe,"' CSSe,"' and CSei8' have been determined using H e I,'*' H e 11,179and Ne 17" 17' 172 17' 17'

17" 177

I78

""

''I

W. N. Lipscomb, J. Chern. Phys., 1974, 60, 5138. 1. N. Krupskii, A. 1. Prokhvatilov, A. 1. Erenberg, and L. D. Yantsevich, Phys. Status Solidi ( A ) , 1973, 19, 5 19. N . S. Hush and M. L. Williams, J. Mol. Spectroscopy. 1Y74, 50, 349. R. L. Amey, J. Phys. Chern., 1974, 78, 1968. S. Bihl, J.-P. Fouassier, and R. Joeckle, Cumpt. rend., 1974, 278, R , 107. A. G. Maki and R. LA. Sams. J. Mol. Spectroscopy, 1974, 52, 233. S. Ogawa and M. Ogawa, J . Mol. Spectroscopy, 1974. 49, 454. A. Zecchina and F. S. Stone, J.C.S. Chern. Cornrn., 1974, 582. T. K. McCuhbin, J. Pliva, R. Pulfrey, W. Telfair, and T. Todd, J. Mol. Spectroscopy, 1974. 49, 136. J. L. Gardner a n d J. A. R. Samson, J. Eleciron Spectroscopy, 1973, 2, 259. J. L. C a r d n e r and J. A. R. Samson, Chem. Phys. Letters, 1974, 26, 240. D . C. Frost, S. T. L.ec, and C. A. McDowell. J. Chern. Phys.. 1973, 59, 5484.

217

Elements of Group IV

11*0 radiation. A correlation diagram of ionic states, of CO:, CS:, CSe:, COS', COSe', and CSSe', has been produced .Ia1One particularly interesting trend emerges. The energy of each ionic state is lowered by substitution of a heavier end atom; the effect of substitution of S by Se is much smaller (C1 eV) than that of 0 by S or Se (>1eV). This reflects the well-established fact that the resemblance between two successive elements in a Periodic Group is closer as one proceeds down the Group.18' The Auger electron spectrum of C,O, has been recorded;'8z both COlS3and CS21a4have been subjected to electron-impact ionization studies, and COS has been studied by both and molecular beam electric resonance s p e ~ t r o s c o p y . ~ ~ ~ + ~ ~ ~ The reactions of a number of atoms (H, F, 0, S), radicals (OH), diatomic molecules (N2,02),and ions (He',Ne',H+,O-) with these molecular species have been studied; the systems examined are summarized in Table 11. Several reactions of CO with 0, OH, 02,and 0- are included in Table 11;

Table 11 Reactions of CO, CS, CO,, COS, and CS, with atoms, radicals, molecules, and ions that have been studied recently H+CO" H + COzb F + CO' 0 + Cod.'

0 + CVR 0 + C02" 0 + CS2'.' S+COS"

OH + CO' N, + COP 0, +Cog*' He* + CO"

He++ COzb Ne'+ COzh H' + COzb 0-+ co

H. Y. Wane, J. A. Eyre, and L. M. Dorfman, J . Chem. Phys., 1973, 59, 5199; M. J. Haugh and J. H. Birely, J. Chem. Phys., 1974, 60, 264; R. Milstein, R. L. Williams, and F. S. Rowland, J. Phys. Chem., 1974,78,857; E. C. Y. Inn, J. Chem. Phys., 1973,59,5431; E. C. Y. Inn, J . Chem. Phys., 1974, 61, 1589; H. T. Powell and J. D. Kelley, J. Chem. Phys., 1974, 60, 2191; N. Djeu, J. Chem. Phys., 1974,60,4109; S. C. Baker and A. M. Dean, J. Chem. Phys., 1974, 60, 307; ' I. R. Slagle, J. R. Gilbert, and D. Gutman, J . Chem. Phys., 1974,61, 704; J . Geddes, P. N. Clough, and P. L. Moore, J. Chem. Phys., 1974,61,2145; " R. B. Klemm and D. D. Davis, J. Phys. Chem., 1974, 78, 1137; C. J. Howard and K. M. Evenson, J . Chern. Phys., 1974, 61, 1943; D. D. Davis, S. Fischer, and R. Schiff, J . Chern. Phys., 1974,61, 2213; I. W. M. Smith and R. Zellner, J.C.S. Faraday 11, 1973, 69, 1617; R. A . Young and W. Morrow, J. Chem. Phys., 1974, 60, 1005; W. T. Rawlins and W. C. Gardiner, J. Phys. Chem., 1974, 7 8 , 4 9 7 ; C. H. Yang and A. L. Bedad, J.C.S. Faraday I, 1974, 70, 1661; M. A. Coplan and K. W. Ogilvie, J. Chem. Phys., 1974, 61, 2010; M. McFarland, D. L. Albritten, F. C. Fehsenfeld, E. E. Ferguson, and A. L. Schmeltekopf, J. Chem. Phys., 1973, 59, 6629. a

'

many other investigations of the oxidation of CO have been published during the period of this Report. The majority describe the catalytic effect of either metals (Mo,lE8Pd,lE9Pt,189p191 A,"') or oxides [Ti0,,lg2 Sn0,1x2

L. Karlsson, L. 0. Wcrme, T. Bergmark, and K. Siegbahn, J. Electron Spectroscopy, 1974, 3, 181. I w 3K. C. Smyth, J . A. Schiavone, and R. S. Freund, J. Chem. Phys., 1974, 60, 1358. IR4 M. Toyoda, T. Ogawa, and N. Ishibashi, Bull. Chem. SOC. Japan, 1974, 47, 95. 1x5 M. Bogey, A. Bauer, and S. Maes, Chem. Phys. Letters, 1974, 24, 516. lS6 R. E. Davis and J. S. Muenter, Chem. Phys. Letters, 1974, 24, 343. 187 J. M. L. J. Reinartz and A. Dynamus, Chem. Phys. Letters, 1974, 24, 346. S. J . Atkinson, C. R. Brundle, and M. W. Robcrts, Chem. Phys. Letters, 1974, 24, 175. A. V. Sklyarov, A. G. Vlasenko, and I. I. Tret'yakov, Russ. J. Phys. Chem., 1973,47, 1622. R. L. Palmer and J. N. Smith, J. Chem. Phys., 1974, 60, 1453. J. P. Dauchot and J. van Cakenberghe, Nature Phys. Sci., 1974, 246, 61. 192 J.-M. Herrmann, P. Vergnon, and S. J. Teichner, Cornpt. rend., 1974, 278, C, 561.

218

Inorganic Chemistry of the Main- group Elements C U O , ’ V20,-M,0 ~~ (M = alkali o n the oxidation. The oxidation of CO to CO, in melts containing V,O, and alkali-metal oxides has been investigated in the temperature range 440-640 0C.194 Molten salts have the advantage over ‘solid’ catalysts in that they operate without being poisoned. The oxidizing capacity of the melts is limited only by the depletion of V,O, and the formation of the insoluble product, V204,via reaction (36). The melts may, however, be reactivated easily by treatment with oxygen.194

v,o, 4- co +

v204

co,

(36)

A mass-spectrometric investigation of the ionic species present during both the oxidation of C O and the decomposition of CO, in an r.f. discharge has been undertaken.”, A particularly interesting feature is that C+is one of the predominant ions; an analysis of the reaction mechanism suggests that it is formed in reaction (37). Cross-sections for the production of 0; and CCo++co+c++co,

(37)

by dissociative electron attachment in CO, have been measured.lY6Independent analyses of the kinetics of both CO”’ and C0,”8 dissociation behind shock waves have also been undertaken. CS, dissociation in a vitreous carbon cell has been studied using mass-spectrometric techniques;lg9CS and S are the only detected products, indicating that (38) is the dominant reaction. The temperature dependence of the concentrations of the products, however, suggests that reaction (39) is also ~ i g n i f i c a n t . ’The ~ ~ results CS,+CS+S CS, + C(wal1) + 2CS

(38)

(39)

of a mass-spectrometric study of the loss of gas-phase CS have been presented The principal loss mechanism is a heterogeneous wall reaction producing CS, and a carbon-rich wall deposit. The reaction does not appear to be accompanied by the formation of a solid CS polymer, as has been assumed previously.2o” Photoionization of C0,201and C0,-CO-0, mixturesZo2has been studied by two groups of workers. In C0,-CO mixtures, interaction of CO: ions leads to the production of (CO); and [(CO),CO,l+ cluster ions; photoionization of C0,-CO-0, mixtures, however, yields mainly oxygen-containing

’” ‘”

M. J . Fuller and M. E. Warwick, J.C.S. Chem. Cornm., 1974, 5 7 . A. Block-Bolten, B. J. M. Bertrand, and S. N . Flengas, Canad. J. Chern., 1974, 52, 2068.

L. C. Brown and A. T. Bell, J. Chern. Phys., 1974, 61, 666. D. Spence and G. J . Schulz, J. Chern. Phys., 1974, 60, 2 16. R. K. Hanson, J. Chern. Phys., 1974, 60, 4970. l Y x J . H. Kiefer, J. Chern. Phys., 1974. 61, 243. l Y y7. C . Peng, J. Phys. Chem., 1974, 78, 634. 200 R. J . Richardson, H. T. Powell. and J. D. Kelley, .1. Phys. Chem., 1973, 77,2601. K . E. McCulloch, J. Chem. Phys., 1973, 59, 4250. *‘I2 L. W. Sieck and R. Gordon, J. Res. Nut. Bur. Stand., Sect. A, 1974, 78, 315. I‘”

lY7

219 Elements of Group IV clusters. Investigation of CO-0, mixtures also revealed reactions between 0: and CO. The role of impurity reactions involving HzO is considered in detail and the implications of all data to the vapour-phase radiolysis of CO, are discussed.202A wide range of heteromolecular clusters containing CO and/or CO, together with SO,, NO, or HzO has been found in isentropically expanding jets;2o3the observed clusters and their formation conditions are summarized in Table 12. These clusters, particularly the hydrates, are of importance in atmospheric chemistry since favourable conditions for their formation are known to be present in jet-aircraft e x h a u ~ t s . ~ ~ ~ The electrochemical fluorination of COS has been carried O U ~ . " ~Cleavage of the C-S bond occurs, giving rise to COF, and SF,; small quantities of CF, and CF,OOCF, are also produced.

Table 12 Heteromolecular clusters of CO, CO,, SO,, NO, and H,O Cluster

Matrix-isolation techniques have been used to study reactions of small molecules (CO) with ionic compounds.205An analysis of the i.r. spectra of NiF,, NiC12, CaF,, CrF,, MnF,, CuF,, or ZnF, with, inter aha, C O in Ar matrices has shown that perturbations of the frequencies of both components occurs; such perturbations are thought to be indicative of interaction between the two components. The pyrolysis of C,0,206and CSZ2O7has been studied independently; that of C,O, [equation (40)] has been studied in the range 600-700°C and GO, + co+c20;

c 2 0+

co+c

(40)

20-100 rnmHg.'O6 The reaction is first-order and is strongly inhibited by NO. The reaction of C30z with NzO, however, is not inhibited by NO. Analysis of the reaction products shows the material balance (41). A 4C,O2 + NZO + N, + CO, + 7CO + 4C

(41)

reaction mechanism involving a bimolecular heterogeneous initation (42),

"'' 204

205 2oh '07

J. M. Calo, Nature, 1974, 248, 665. S. Nagase, H . Baba, K . Kodaira, and T. Abe, Bull. Chem. SOC.Japan, 1973, 46, 3435. D. A. van Leirsburg and C. W. DeKock, J . Phys. Chem., 1974, 78, 134. M.-M. Bonneau and C. Ouellet, Canad. J . Chem., 1974, 52, 167. J.-L. Destornbes and C. Marlikre, Compt. rend., 1973, 277, €3, 427.

Inorganic Chemistry of the Main - group Elements

220

followed by a small chain reaction (43)-(43, has been proposed.206

+ NZO

c 3 0 2

4

(c303) +

Nz + (c303)

(42)

coz +

(43)

c 2 0

CZO + co + c

c, -!-

c 3 0 2

-+

(44)

2c0 + Cn+l

(45)

Carbonates, Thiocarbonates, and Related Anions. Data for this section of the Report have been collected only for the simple compounds of the Main-group elements; those describing the chemistry of, for example, rare-earth metal carbonates o r transition-metal carbonato complexes have been excluded. A comprehensive single-crystal X-ray study of KHCO, and KDCO, has been carried out by Thomas et al.'"' at three different temperatures (95, 219, 298 K). The unit cells are monoclinic, space group P 2 , l a ; their dimensions are collated in Table 13. The KHCO, structure, compris-

Table 13 Unit-cell dimensions of KHC03,KDC03,and PbCO, at 298 K KHCO, KDCO, PbCO,

a/A 15.1725 15.1948 5.1800

bJA 5.6283 5.6307 8.492

CIA

3.7110 3.7 107 6.133

81"

104.63 1 104.567 -

ing (HC03):- dimers and K' cations, is isomorphous with its deuteriated counterpart. The heavy atoms of each HCO, ion within the centrosymmetric dimer are closely coplanar at all temperatures, the separation between the two planes being ca. 0.22 A; details of this aspect of the structure of the dimeric anion are given in Table 14. The molecular geometries of the two

Table 14 The planarity of the [(HCO3)J- dimer." The two parallel planes through the oxygen atoms of each HC05 ion are taken a s references ; the notation is defined a s follows: (02')

03'

Perpendicular distancestA at 298 K A

D 6

KHCO, 0.222(3) 0.09(3) 0.004(3 )

KDCO, 0.2 19(3) 0.03 (3) O.OOS(3)

Reproduced by permission from Acta Cryst., 1974, B30, 1155. ""

J. 0. Thomas, K. Tellgren, and I. Olavsson, Acta Cryst., IY74, B30, 1155. K. Sahl, Z . Krist., 1974. 139, 215.

01'

22 1

Elements of Group IV m

isotopic anions and their temperature dependences are shown in Figure 2; the two symmetry-related 0-H - - - 0 hydrogen bonds within the two dimers (HC0,):- and (DC0,):- have bond lengths 2.585 and 2.607A (at 298 K), respectively.'" The crystal structure of cerussite, PbCO,, has been refined.209It is isotypic with aragonite and crystallizes with orthorhombic symmetry, space group P, ; the unit-cell dimensions are included in Table 13. The configuration of the CO, group is discussed in relation to the structures of aragonite, strontionite, and witherite.'09 A detailed study210of the crystal structures of M,CO, (M = Li, Na, or K) between ambient temperatures and their melting points has shown that although Li,CO, has but one (monoclinic) crystalline modification, Na2C0, and K,CO, exist in three structures, with the thermal evolution: ordered monoclinic

.

-Na2COj.349 "C --K2C03,340"C

disordered monoclinic

'"'

G . Papin, Compt. rend., 1973, 277, C, 691.

479 "C

hexagonal

(46)

222

Inorganic Chemistry of the Main- group Elements

Raman studies of KHCO,"' and CaCO, (calcite)212have been carried out; the far-i.r. spectrum of KHC0,211has also been reported.'12 The vibrational have been determined by spectra of matrix-isolated CO; and COj Jacox and Milligan. The absorptions which appear near 1600 cm-' on codeposition of Ar-CO, mixtures with an alkali metal at 1 4 K have been assigned to v 3 of an M' - - CO; ion pair with an OCO valence angle near 130°.213 Stabilization of COT in an Ar matrix at 14 K has been achieved by codeposition of Ar-C02-N20 or Ar-CO-0, mixtures with The i.r. data require a CZustructure for the ion; although this deviation of the structure from the expected D,, symmetry may result in part from Jahn-Teller distortion, evidence that cation interactions play a significant role has been found. Several reactions of carbonates with oxides (both lid^^^-^^^ and gaseO U S ~have ~ ~ )been investigated. The reactivity of Na,C03 with vanadium oxides increases in the order V,O, < V,O, < V,O,, < V204;2'5 this sequence has been rationalized in terms of the vanadium oxidation state. The lowest reaction rate, however, was observed in the Na2C03-V203reaction, which is restricted by the formation of Na, 3 3 v 2 0 3 . 1 7 solid solutions. The sequential products of the reaction of BaCO, and Al,03 in the temperature range 700-1 100 "C are dependent on the reactant ratios;216the data obtained are summarized in Table 15. The kinetics of the reaction of SrCO, and WO,

Table 15 Products of the BaCO,-Al,O, BaCO, :A1,0, ratio 1:l 1:6 3: 1

reaction.'I6

Initial products BaAI,O,, CO, BaAl,O,, CO, BaAl,O,, CO,

Final products BaALO,, CO,

BaA1,z019,COz Ba,Al,O,, 3C0,

[reaction (47)I2l7and the products of the reaction of CaC03 and anorthite, CaAl,Si,O,, [reaction (48)I2l8have also been the subjects of detailed investigation. It has been established recently that CO: is stable in fused KNO, SrCO, + WO, -+ SrWO, + CO, 3CaC0, + 2CaA12Si208 + Ca,Al,Si,O,

(47)

+ Ca,Al,Si,O,, + 3c0, (48)

at 350 "C, thus clarifying previous disparate results.219Purging the melt with 21 I

G . Lucazeau and A. Novak, J . Raman Spectroscopy, 1973. 1, 573. S . A . Akhmanov, N. I . Koroteev, and A. I. Kholodnykh, J . Raman Spectroscopy, 1974, 2, 239. 'I' M. E. Jacox and D. E. Milligan, Chem. Phys. Letters, 1974, 28, 163. ' I 4 M . E Jacox and D. E. Milligan, J . Mol. Spectroscopy, 1974, 52, 363. 2 1 5 V. L. Volkov, N. Kh. Valikhanova, and A. A. Fotiev, Russ. J . Inorg. Chem., 1973, 18, 1707. ' I h J. Beretka and T. Brown, Austral. J. Chem., 1973, 26, 2527. 2 1 7 C . Flor, V. Massarotti, and R. Riccardi, Z. Naturforsch., 1974, 29a, 503. ? I x G. Hoschek, Naturwiss., 1973, 60, 548. 21u A . G. Keenen. C . G. Fernandez, and T. R. Williamson, J. Electrochem. SOC.,1974, 121, 885. 'I2

Elements of Group IV

223

oxygen or nitrogen has no effect; Cr,O?, however, will react stoicheiometrically with C0:- in the melt according to reaction (49).'l9

The reaction of variously hydrated samples of CaC03 with N204 and NOCl has been studied at temperatures up to 200°C.220The reaction schemes (50) and (51) have been confirmed for the two reactions; that of N204 with CaCO, occurs much faster than that of NOC1. It has been CaCO, + &O4

-+Ca(NO,),

+ N O +C 0 2

+ 3 N 0 + 3Coz + 3CaC1, CaCO, + zN204+ Ca(N03),+ NO + CO, 4CaC03+ 6NOC1+ Ca(NO,), + 4 N 0 + 4 c O , + 3CaC1, 3CaC0, + 6NOCl+ &O4

(5 l a ) (5 1b) (51c)

suggested that these reactions may form the basis of an analysis for mixtures of NzO4 and NOCl, the amount of chlorine present in the solid produhs being indicative of the gas-phase concentration of NOC1.220 Phase relationships in the Na2C03-CaC03-Hz0,22' KHC0,-KN0,H,0,222 NaC1-NaBr-Na,C03,223 NaBr-NaI-Na,C03,224 and NaCl-NaINa2C0:" ternary systems involving carbonates have been examined. Cyanides, Cyanates, and Derivatives of Group V Elements.-Cyanogen, Related Species. The number of papers published during the period of this Report which describe the chemistry of these species is markedly lower than that for previous Reports. Theoretical calculations of the electronic struc~ ' ~ ~been ~ * successfully tures of HCN,225HNCS,2z6and the CN r a d i ~ a l ~ have completed. The electronic structure of HNCS has been compared with that of HNCOZz6and it is concluded that (i) the .rr-system in HNCS involves a nitrogen lone pair stabilized by a C-S .rr-bond, whereas the n-system in HNCO consists of a C-0 .rr-bond stabilized by the nitrogen lone pair, and (ii) the d-orbitals of sulphur accept electron density in a u - rather than a .rr-fashion. The electronic structure of the NCS- ion has also been determined experimentally from the X-ray KB fluorescence and K absorption spectra of the S atom in KSCN.Z29 22" 221

222 221

224 225

22h

'*' ***

229

D. Bourgeois, P. Zecchini, and C. Devin, Compt. rend., 1974, 278, C, 53. E. J. Frankis and D. McKie, Nature Phys. Sci., 1974, 246, 124. P. S. Bogoyavlenskii and E. D. Gashpur, Russ. J. Inorg. Chem., 1973, 18, 1662. R. P. Lagutova, D. G . Barsegov, A. G. Yakovlev, and 1. I. Il'yasov, Russ. J . Inorg. Chem., 1973, 18, 760. I. I. Il'yasov and V. V. Volchanskaya, Russ. J. Inorg. Chem., 1973, 18, 761. G. M. Schwenzer, S. V. O'Neil, H. F. Schaefer, C. P. Baskin, and C . F. Bender, J. Chem. Phys., 1974, 60, 2787. J. M. Howell, I. Absar, and J. R. Van Wazer, J. Chem. Phys., 1973, 59, 5895. G. Das, T. Janis, and A. C. Wahl, J. Chem. Phys., 1974, 61, 1274. P. carsky, M. Machatek, and R. Zahradnik, Coll. Czech. Chem. Comm., 1973, 38, 3067. A. P. Sadovskii, L. N. Mazalov, T. I. Guzhavina, G . K. Parygina, and B. Yu. Khel'mer, J. Struct. Chern., 1973, 14, 618.

224

Inorganic Chemistry of the Main- group Elements Ab initio calculations of the molecular geometry and vibrational properties of the hydrogen-bonded complex between H CN and HF have been effected.230The complex (24) is predicted to be linear, HF being the proton

2 833 K

(23)

donor and HCN donating a lone pair to the hydrogen bond. Hydrogen bonding in mixed crystals of HCN and DCN has been studied as a function of composition using i.r. spectroscopic techniques.231 Detailed examinations of the i.r. spectra of (CN),,'32 HCN0,2333234 DCN0,234and XCNS (X = H or D)*" have been carried out; an analysis of the Raman spectra of (CN),,23"XCN (X = H o r D),"' and XCNS (X = H or D)'" has also been undertaken. Several other spectroscopic studies of (CN), (vacuum-u.v.),'38 HCN (electron energy H C P (U.P.S.),'""NH2CN (U.P.S.),24'and DCNO (mm wave)'"' have been described during the period of this Report. The phosphorus analogue of HCN, methiophosphide, HCP, has been prepared by passage of PH, through a low-intensity rotating arc struck between a pair of carbon The experimentally determined adiabatic ionization potentials of this molecule, which is unusual in that it is the only compound isolated with a P atom bonded to only one neighbouring atom, are compared with theoretically derived values in Table 16. Also included are the associated frequencies of the U.P.S. bands and the orbital assignments.

Table 16 Adiabatic ionization potentials of HCP'"' Adiabatic ionization po te n tialle V Theore tica 1 Experimental 10.0 10.79f 0.01 12.6 12.86f 0.01 20.0 -

Associated wave n urn berlcm- ' 1110f30(v,) 1250 f30(v,) -

Orbital assignment 1r-(C-P bonding) 3a-(P lone pair) 2u-(C-H bonding)

The oxidation of (CN), in (CN),-02-Ar mixtures and the distribution of the reaction products before and after ignition have been studied behind L. A. ('urtiss and J. A . Pople, J. Mol. Spectroscopy, 1973, 48, 113. H . 6 . Friedrich and P. F. Krause, J. Chem. Phys., 1973. 59, 4942. '" A. Picard, Spectrochim. Acta, 1974, 30A, 691. ''' E. L. Ferretti and K. N. Rao, .1. Mol. Spectroscopy, 1Y74, 51, 97. B. P. Winnewisser, M. Winnewisser, and F. Winther, J. Mol. Spectroscopy, 1974, 51, 6 5 2 3 5 G. R . Draper and R. L. Werner, .J. Mol. Spectroscopy, 1974, 50, 369. L.. H. Jones. J. Mo l. Spectroscopy, 1974, 49, 82. 237 J. Bendtsen and H. Cr. M. Edwards, J. Raman Spectroscopy, 1974, 2, 407. 2 3 x R. E. Connors, J. L. Roebber, and K. Weiss, J . Chem. Phys., 1974. 60, 501 1. "" W.-C. T a m and C. E. Brion, J. Electron Spectroscopy, 1974. 3, 28 1. W' D. C . Frost, S. T. Lee, a n d C. A . McDowell, Chem. Phys. Lrttrrs. 1Y73. 23, 472. H. Stafast and H. Bock, Chem. Ber., 1974, 107, 1882. M. Winnewisser and B. P. Winnewisser, Z . Naturforsch., 1974. 29a, 633. 230

"

Elements of Group IV

225

reflected shock In stoicheiometric mixtures, the major products before ignition are NZ, CO, and some COz, which disappears after ignition. In mixtures with excess oxygen, however, the products following ignition are N,, CO,, and some CO. The complex BeC12,2NCC1 has been produced by the addition of anhydrous BeC& to an excess of liquid CNCl at 0 "C, and its chemistry compared to that of the analogous BeC1,,2NCCH3 complex.244 Although BeC1,,2NCCH3 is slightly more thermally stable (d. 210 "C) than BeClZ,2NCC1(d. 120"C), they both undergo the same reaction (52) with BeC1,,2NCR

+ 2L -+BeClZ,2L+ 2RCN

(52)

R = C1 or Me; L = Et,O, MeCN, or PhCN polar solvents. A t temperatures above 0 "C, BeC12,2NCC1 acts as a catalyst in the formation of trichloro-s -triazine (CNCl), from liquid CNC1.244The formation of 1: 1 complexes of SCN- with SOz, S0Cl2, and SOzC12 has also been A u ~ t a d ' ~ ~ has * ' ~ 'published the results of a study of the reactions of CNand (XCN), (X = S or Se)'"' in anhydrous acetonitrile. He with s4062-246 postulates that the mechanism of the CN--S402interaction involves nucleophilic displacement of ionic S,O:- by CN- [reaction (53)J followed by

+ CN- + -03S-SCN + S20:-

-03s-S-S-SOY

(53)

a fast nucleophilic attack of the unstable thiocyanatosulphonate ion by CNto give ionic SCN- and the cyanosulphonate ion [reaction (54)].246 The O3S-SCN

+ CN- -+ -O-&-CN

+ SCN-

(54)

mechanism of the CN--(XCN), reaction was studied by isotope tracer techniques involving the addition of four moles of "CN- t o one mole of The two reaction mechanisms are similar; they involve fast substitution by CN- at one of the chalcogen atoms, the chalcogen dicyanide so formed reacting with CN- t o farm [X(CN),]- as shown in reaction ( 5 5 ) .

(XCN),

+

"CN-

-

XCN

+X

71

C 'N

3

~

NC\ -

~

);""

X

I

(55)

"CN

With [Se(CN),]-, the cyanide groups are labile, fast exchange occurring with the 13CN- in the solvent; the 13C:12Cratio in [Se(CN),]- is thus changed to 4:1, which is the overall 13C:12Cratio [one carbon of the (SCN), is fixed as 241 244 245

246

247

A. Lifshitz, K . Scheller, and D. Bass, J. Chern. Phys., 1974, 60, 3678. J. MacCordick, Cornpt. rend., 1974, 278, C, 1 1 77. S. Wasif and S. B. Salama, J.C.S. Dalton, 1973, 2148. T. Austad, Acta Chern. Scand. (A), 1974, 28, 693. T. Austad, Acta Chern. Scand. (A), 1974, 28, 806.

Inorganic Chemistry of the Main-group Elements 226 SCN-I. No exchange occurs with [S(CN),]-, the 13C:12Cratio being maintained at 2 : l . Both [S(CN),]- and [Se(CN),]- decompose slowly to give cyanogen and either SCN- or SeCN- [reaction (56)]; the 13C:12Cratio in the thiocyanate being 2 : 1, that in the selenocyanate is 4:l. Finally, the cyanogen rapidly adds two moles of CN- [reaction (57)].247

-

NC

(CN), + 2CN

( 57)

N

CN

Ag"', CuIII, and Nil" have been used as catalysts in the persulphate oxidation of, inter a h , KCN and KSCN.24*In the absence of the catalysts, the nitrate state is not reached in alkaline medium; the catalytic activity in attaining this stage follows the order Ag"' > CulI1> Nil". When small amounts of KSCN are added to molten NaN03-KN03 eutectic mixtures at temperatures between 230 and 316 "C, a complex and relatively violent reaction occurs.249NO;, SO:-, and basic ionic species are formed in the melt, together with NO,, C 0 2 , (CN),, N 2 0 , and minor quantities of other gaseous products. Finally, the first example of solid linkage isomers containing N- and 0 -bonded cyanate groups has been reported in the compounds Rh(PPh,),NCO and Rh(PPh,),0CN.250The i.r. spectra of the isomers have been discussed and the solvent dependence of the mode of co-ordination has been noted. 2 Silicon, Germanium, Tin, and Lead reactions of Hydrides of Silicon, Germanium, and Tin.-Ion-molecule silane mixtures studied by mass-spectrome tric methods have continued to provoke attention. Protonation of SiH, by proton transfer from CH; or NH: affords the silanium ion SiH:. Chemical non-equivalence of the hydrogens in SiH: has been deduced from the exclusive formation of HD from the reaction of SiD,H' with ammonia, leading to the preference of structures with symmetries lower than the D,, trigonal-bipyramidal Ion-molecule reactions in monosilane that represent a net hydride-ion transfer proceed via a direct, stripping-type process, yielding an ion with very low kinetic energy, and by a complex-formation mechanism leading to a scrambling of H and D atoms.252The principal reaction in monosilane-water mixtures is one of hydride-ion transfer from monosilane

'" 24')

-,511

"'

'''

P. K . Jaiswal and K. L. Yadava, Indian J. Chew.. 1973, 11, 5Y8. M. E. Martins, A . J . Calandra, and A . J . Arvia, J . Inorg. Nucleur Chem.. lY74, 36, 1705. S. J . Anderson, A . 11. Norbury, and J . Songstad, J.C.S. Chem. Cornrn., 1974. 37. M . D. Sefcik, J . M. S. Henis, and P. P. Gaspar, J. Chew. Phys., 1974, 61, 4320. T. M . Mayer and F. W. Larnpe, J . Phys. Chem., 1974. 78, 2195.

Elements of Group IV 227 to ions derived from The reactions of primary ions formed from methane with monosilane and of primary ions formed from monosilane with methane have been studied using monosilane-methane mixtures. All primary ions of each constituent undergo at least one ion-molecule reaction with the opposite molecule, but by far the most predominant such cross-reaction is again hydride transfer from monosilane to primary ions of methane, producing the SiH: Ion-molecule reactions in disilane have been studied by similar techniques. All primary ions react with the parent molecule, resulting in a polymerization to higher silicon hydride~."~ Model calculations 01 the displacement reaction of H atoms with disilane have suggested that the reaction proceeds via a bridged activated complex rather than a linear Structural parameters for GeH,X, (X = Cl or Br)257and also for Me,SnH and Me2SnHZz5* have been determined by electron diffraction. All four molecules are tetrahedral in the gas phase, with principal bond distances as follows: GeH,Cl, r(Ge-C1) = 2.130(3), r(Ge-H) = 1.56(2); GeH,Br, r(Ge-Br) = 2.277(3), r(Ge-H) = 1.52(4); Me,SnH r(Sn-C) = 2.147(4), r(Sn-H) = 1.705(67); Me,SnH, r(Sn-C) = 2.150(3) r(Sn-H) = 1.680(15)A. Structural data (ratios of interatomic distances and bond angles) have been calculated from 'H and 'H n.m.r. spectra for CD3SiH3, CH3SiD3,CD,GeH,, and CH,GeD3 dissolved under pressure in the nematic phase of p-ethoxybenzylidene-g -n-butylaniline. The data obtained are in good agreement with those deduced from microwave and other The heights of the barriers to internal rotation in CF,GeH,26" and CHzFGeH,26'have been measured to be 1280 f 150 cal mol-' and 1390 f 40 cal mol-', respectively, from microwave data, whilst the barriers to rotation in CH3SiH32"2*2"3 and disilane'"' have been the subject of theoretical calculadisilane,'", organosilanes and tions. The dipole moments of CH3SiH3,263vz64 halogeno-organosilanes,265 and CH3GeH3and H,GeX (X = C1, Br, or I)'" have been determined. Stannic bromide has been used as a selective brominating agent for silanes. Monosilane, disilane, and the methylsilanes Me,SiH,-, (n = 1-3) all react to convert one Si-H bond into a Si-Br bond with no trace of

"' T. M.

H. Cheng and F. W. Lampe, J. Phys. Chem., 1973, 77, 2841. T. M. H. Cheng, T. Y . Yu, and F. W. Lampe, J. Phys. Chem., 1973, 77, 2587. 25s T. M. H. Cheng, T. Y. Yu, and F. W. Lampe, J. Phys. Chem., 1974, 78, 1184. 256 I. Safarik, T. L. Pollock, and 0. P. Strausz, J. Phys. Chem., 1974, 78, 353. 257 B. Beagley, D. P. Brown, and J. M . Freeman, J. Mol. Structure, 1973, 18, 335. 25R B. Beagley, K. McAloon, and J. M. Freeman, Acta Cryst., 1974, B30, 444. 2 5 9 R. Ader and A. Loewenstein, J. Amer. Chem. SOC., 1974, 96, 5336. "'L. C. Krisher, W. A. Watson, and J. A. Morrison, J. Chem. Phys., 1974, 61, 3429. 26 I L. C. Krisher, W. A. Watson, and J. A. Morrison, J. Chem. Phys., 1974, 60, 3417. ''' C. S. Ewig, W. E. Palke, and B. Kirtman, J. Chem. Phys., 1974, 60, 2749. 26' M. S. Gordon and L. Neubauer, J. Amer. Chem. Soc., 1974, 96, 8690. 264 J. M. Bellama, R. S. Evans, and J. E. Huheey, J. Amer. Chem. Soc., 1973, 95, 7242. 2 6 5 A. N. Egorochkin, N . S. Vyazankin, and M. G. Voronkov, Doklady Akad. Nauk S.S.S.R., 1973, 211, 616. "' J. M. Bellama, S. 0 . Wandiga, and A. A. Maryott, J.C.S. Faraday 11, 1974, 70, 719. 254

228

Inorganic Chemistry of the Main-group Elements

dibr~mination.~ Trichlorosilane '~ selectively reduces the phosphonyl group of S,1O-dihydro-S-phenyldibenzo[b,e]phosphorin-lO-one 5-oxide to the corresponding ketophosphine in 90% yield.268U.V. irradiation of gaseous mixtures of trifluoro- or trichloro-silane with trifluoronitrosomethane results in the formation of the 0-(trihalogenosily1)-N-(trifluoromethy1)hydroxylamine in small yield .269 Hydrosilylation of carbon-carbon multiple bonds and other similar systems has been the subject of several investigations, mechanistic aspects of catalytic processes being particularly studied. The addition of trichlorosilane to the C=C bonds of model polyalkadienes takes place in the presence of hexachloroplatinic acid under pressure and at high temperature, the reaction rate depending on the nature of the double bond involved."" The photochemical addition of trichlorosilane with fluorinated olefins gives different amount of products depending on the concentration of the reactants. With excess trichlorosilane the major product of reaction with 2chloro-1,1-difluoroethylene is trichloro-(2,2-difluoroethyl)silane together with smaller amounts of trichloro-( 1,1-difluoroethyl)silane. The same reaction with excess of olefin gives mainly trichloro-(2-chloro-2,2-difluoroethy1)silane accompanied by trichloro-(2-chloro-1,1-difluoroethyl)silane. The formation of these products may be rationalized by initial trichlorosilyl radical addition to 2-chloro-l,l-difluoroethyleneat the CF, group and a competing reduction of the olefin to 1,l-difluoroethylene followed by trichlorosilyl radical addition at the CH, group. Photochemical reaction of trichlorosilane with 2-bromo-1,l -difluoroethylene gives the reduction product 1,1-difluoroethylene and 2,2-difluoroethyl- and 2-bromo-2,2-difluoroethyl-trichl~rosilanes.~~~ The kinetics of the addition of trichlorosilane to acetylene at 100 "C catalysed by polymer-supported chloroplatinic acid have been studied and correlated by equations derived for heterogeneously catalysed reactions. The addition of the product, vinyltrichlorosilane, to the initial reactants had a rate-enhancing effect.272The stereochemistry of the addition of dichlorosilane to acetylenes has also been studied in the presence of chloroplatinic acid, platinum on carbon, and benzoyl peroxide as catalysts. Platinum-catalysed additions proceed in a stereospecific cis manner, giving trans -adducts, whereas peroxide-catalysed additions gave predominantly cis -adducts except for 3,3 -dimethylbut- 1-yne, which gave largely the trans Stereospecific trans addition of triorganosilanes to acetylenes is also achieved by the use of tris(tripheny1phosphine)rhodium

N. S. Hosmane, Inorg. Nucleur Chem. Letters, 1974, 10, 1077. Y. Segall, I. Granoth, and A. Kalir. J.C.S. Chem. Cornrn., 1974, 501. "' A. A. Kirpichnikova, V. G . Noskov, M . A . Sokal'skii, and M. A . Englin, J . Gen. Chern. ( U . S . S . R . ) , 1973, 43, 1852. 270 C . Pinazzi, J . C. Soutif, and J . C. Brosse, Buli. S O C . chirn. France, 1974, 2166. 271 W. 1. Bevan, R. N . Haszeldine, J . Middleton, and A. E. Tipping, J.C.S. Dalton, 1974, 230.5. 2 7 2 M. Kraus, Coll. Czech. Chern. Cornrn., 1974, 39, 1318. 2 7 3 R . A . Benkeser and 0. F. Ehler, J. Organornetullic Chem., 1974, 69, 193. 2h7 268

Elements of Group IV 229 chloride as catalyst.274Ziegler-Natta catalyst systems of the types M(acac),AlEt, ( M = N i , Co, or Fe) catalyse the hydrosilylation of 1,3-dienes or terminal acetylenes. Nickel salts provide the best catalysts, and a mechanism which involves the successive formation of a NiO complex, its oxidative adduct L(diene)Ni(H)SiX,, a n-ally1 complex L(n-allyl)NiSiX,, isomeric n-pentenyl derivatives, and finally the hydrosilylation product and the regenerated NiO complex is proposed .275 Hydrosilylation has also been used for the synthesis of silicon heterocyclic compounds. Ring formation from the unsaturated silanes CH,=CH(CH,), SiMe2H (n = 0-6) depends upon the value of n. No ring closure takes place when n = 0 or 1, but cyclic products were obtained when r~ = 2.276Palladium chloride or tris(tripheny1phosphine)rhodium chloride catalyse the addition of triorganosilanes to carbodi-imides to form N-silylformamidines in high yield.”’ Catalytic hydrosilylation using rhodium(1) complexes with optically active phosphine ligands has been employed to achieve asymmetric reduction of The photolysis of H,S in the presence of Me,SiD, leads to the formation of large yields of D,. This apparent exchange reaction is, however, due to a photochain sequence involving the intermediates Me,Si(D)SH and Me2Si(D)S.279Kinetic studies of the ozonolysis of silanes have supported previously proposed mechanisms. The first step involves co-ordination of ozone to silicon followed by electrophilic attack at the Si-H bond.,’’ Product analysis of the flow pyrolysis of Me,GeH is consistent with a decomposition involving Me,Ge’, H , and Me’ radicals. The pyrolysis of Me,SiH is much more complex, presumably due to the formation of silicon-carbon double-bonded intermediates and the Me,Si(H)CH, radical

Silicon Solid-state Chemistry.-Contrary to the pattern adopted in previous volumes, the chemistry of aluminosilicates and zeolites will not be discussed here; the data published during the period of this Report associated with these materials are considered in detail in Chapter 3. In this section, silicon dioxide and the silicates will be described separately; emphasis will be laid on the inorganic chemistry of these compounds, and papers describing solely their catalytic, adsorption, diffusion, and other similar properties will not be considered. Silicon Dioxide. Although most authors in this field are interested in the chemistry of species adsorbed o n the surface of Si02, a limited number of papers have been published describing the physical and chemical properties I . Ojima, M. Kumagai, and Y. Nagai, J. Organometallic Chem.. 1974, 66, C14. T. A. Nile, and S. Takahashi, J. Organometallic Chem.. 1974, 72, 425. ”’ J. V. Swisher and H. H. Chen., J. Organometallic Chrm., 1974, 69, 83. 277 I. Ojima, S. I . Inaba, and Y. Nagai, J. Organometalk Chem., 1974, 72, C11. ’’’ 1. Ojima and Y. Nagai, Chem. Letters, 1974, 223. A. G . Alexander, R. W. Fair, and 0. P. Strausz, J. Phys. Chem., 1974, 78, 203. ’*(’ Yu. A. Aleksandrov and B. I . Tarunin, Doklady Akad. Nauk S . S . S . R . , 1973, 212, 789. D.P. Paquin. R. J . O’Connor, and M. A. Ring, J . Organometallic Chem., 1974, 80, 341. 274

’’’ M . F. Lappert,

’’’ ”’

230

Inorganic Chemistry of the Main- group Elements

of the pure material. Three theoretical investigations of SiO, have been ~ n d e r t a k e n ; ~the ~ ~ co-ordination -~~~ in, and the i.r.283 and Raman283,284 intensities of, single crystals of a - and p-quartz have been calculated. Satisfactory agreement is observed with the experimental spectral data.283,284 An irradiation-induced phase transition of the same kind as the a+ transition has been found in quartz;”’ it occurs at a dose rate of 4-5 X lo’” fast neutrons cmp2. A single-crystal study of the cristobalite inversion has also been carried out.286 Instrumental parameters for the determination of the 0 : S i ratio in SiO, films using Auger electron spectroscopy have been studied and o p t i m i ~ e d . ~ ~ ’ The ratio of the Auger peak heights for the two components is a measure of their relative abundance and can yield meaningful results, when compared with a standard. X-Ray absorption spectra of SiO,, SiO, and Si in the Si K edge region have been The structure of the high-energy absorption edge is strongly influenced by the type of bonding, showing that SiO cannot be a mixture of Si and SiO,. This conclusion confirms that derived from optical measurements and is consistent with the hypothesis that several tetrahedral arrangements different from those associated with Si and SiO, are present in SiO.”’ The nature of the impurity water in synthetic quartzzxyand of the 0- hole centre in natural quartz”” has been examined by i.r. and e.s.r. spectroscopic techniques, respectively. The reaction between SiO, and A1 has been studied as a function of both temperature and SiO, ~rystallinity.~”~ The reaction products formed between 850°C and’ the melting point of A1 are 8-A1,0, and Si. The activation energy of the reaction is dependent on the type of SO,, varying from 31 f 3 kcal mol-’ for vitreous silica to 64*6 kcal mol-’ for quartz; it decreases abruptly at the melting point of Al, and a volatile oxide (probably A1,O) is formed.’”’ F r i e ~ e r has ~ ” ~shown that hydrophobic, hydrophilic, and organophilic SiO, surfaces may be distinguished easily by two independent contact-angle measurements with different liquids. Interest in SiO, surface chemistry has centered, however, on the characterization (principally by means of i.r. and e.s.r. spectroscopy) of the functional groups present on surfaces subjected to ”* *”

V. N. Pak, Russ. J. Phys. Chem.. 1973. 47, 1332. J . Etchepare, M. Merian, and L. Smetankine, J. Chem. Phys.. 1974. 60, 1873.. 284 J. Etchepare a n d M. Merian, Compt. rend., 1974, 278, B, 1071. 2 8 5 E. V . Kolontsbva, E. E. Kulago. and N. A . Toniilin, Souiet Phys. Cryst., 1973, 18, 752. ’“ D. R. Peacor, Z. Krist., 1973, 138, 274. ”’ J . N. Smith, S. Thomas, and K. Ritchie, J. Electrochem. Soc., 1974, 121, 827. *’’ C. Senemaud, M. T. Costa Lima, J . A . Roger, and A. Cachard, Chem. Phys. Letters, 1973,26, 431. ”’ L. I. Tsinober and V. E. Khadzhi, Soviet Phys. Cryst., 1974, 18, 699. ”” M. I. Samoilovich, A . 1. Novozhilov. L. I. Tsinober. and A. G. Malyshev, J. Struct. C‘hem., 3973, 14, 416. ”’ K . Prabriputaloong and M. R. Piggott, J. Electrochem. Soc.. 1973, 121, 430. 2 y 2 R. G. Frieser. J. Electrochem. Soc.. 1974, 121, 669.

23 1 Elements of Group IV various adsorbates. Kondo et al.293 have studied the thermal behaviour of silanol groups on silica gel by i.r. spectroscopy. The broad OH stretching vibrations have been curve-resolved into the component bands as a function of temperature. The spectra became progressively simpler (and composed of fewer component bands) as the temperature was increased (Figure 3). An assignment of the six component bands has been attempted;

Figure 3 OH-stretching absorption bands and their component bands of silanol in various heat-treatment temperatures. a, b, c , d, e, and f show the maximum wavenumbers of the component bands at 3870, 3750, 3630, 3470, 3260, and 3030 cm-I, respectively (Reproduced by permission from Bull. Chem. SOC.Japan, 1974, 47, 553) those at 3030 and 3750 cm-' were assigned to' adsorbed water and free O H groups, respectively, whereas those at 3260, 3470, and 3630cm-' were assigned to hydrogen-bonded OH groups. That at 3870cm-' was not assigned.2931.r. studies of the adsorption of CH,D3-,0H ( 0 s n d 3),'" GH,0H,295t-C,H,OH,*" and various other have been undertaken. Force-constant calculations294utilizing only the CH and CD stretching modes have been used to show that the strongest spectral features of the CH,D3-"OH adsorbed species can be assigned to an unsymmetrical surface SiOMe group with one strong and two weak CH bonds. Some additional spectral features, which grow reversibly in intensity with increasing sample temperature, have been assigned to a symmetrical SiOMe species.294Clusters of C,H,OH and t-C,H,OH were found to adsorb via hydrogen bonding to the SiO, the results obtained have been compared with those of the adsorption of C,H,OH on AlzO,, and the different behaviour of the 2q3 2y4 z95

29h

S. Kondo, M. Muroya, and K. Fujii, Bull. Chem. SOC. Japan. 1974, 47, 553. B. A. Morrow, J.C.S. Faraday I , 1974, 70, 1527. H. Jeziorowski, H. Knijzinger, W. Meye, and H. D. Muller, J.C.S. Faraday I, 1973, 69, 1744. R. G. Azrak and C. L. Angell, J. Phys. Chem., 1973, 77, 3048.

232

Inorganic Chemistry of the Main- group Elements two oxides has been discussed in terms of the different metal-oxygen bond character. Meyer and Basti~k'~'conclude from the results of a number of experiments that H,S is adsorbed on to a silica surface according to a double mechanism: ( a ) by formation of S - - H-0 hydrogen bridges with the surface OH groups, and ( b ) by formation of surface aggregates as a result of S . H-S hydrogen bonding in the adsorbed phase. Glass and Waring,2's however, have interpreted the adsorption isotherms of H2S, CH,SH, C2H5SH, and MezS solely in terms of an adsorbed species involving S - - - H-0 hydrogen bonds between the surface OH and the S atoms of the adsorbate.''* An i.r. study of the reactions between C,H,NCO and SiO, surfaces has been undertaken.2y' 'The products of the adsorption process include a surface urethane, 1,3-diethylurea, a biuret, dissociatively adsorbed isocyanate and ethoxy-groups, and compounds formed by the polymerization of isocyanic acid and HCN. NO3""and the radicals formed by photolysis of CH,IZ3" and CH,OH"* have been studied when adsorbed on SiO, surfaces by e.s.r. techniques. At least two adsorption sites were found for NO;300one is present o n gels pretreated at low temperatures (<500 "C), whereas the other is predominantly on gels pretreated at higher temperatures. The spectra observed after photolysis of CH,I, were attributed to the radical SSi-0-CH,.'"' The radical species --)Si-O-CH,, CH3, HCO, and H were observed in the e.s.r. spectra of the irradiated surface rnethoxide~.~"~ The behaviour of 02, O,, and 0- radicals adsorbed on partially reduced V,O,-SiO, catalysts has also been investigated.,", The character and properties of the surface acid sites of Si0,-Al,O, mixed oxide systems have been investigated using i.r. technique^.^"^ The spectra of adsorbed n-C,H,NH, show that whereas pure S O z , outgassed at 5OO0C, has no acid sites, that outgassed at 100°C in air has very weak protonic acid sites. Similarly, outgassed pure A1,0, has aprotonic acid sites, which are able to change to protonic sites by adsorbing H,O molecules. On Si02-A1203, strong protonic acid sites appear that are not found on the individual oxides; the strength of the acid site increases with increasing SiO, content .304 *

*

Silicates. Although the majority of the data published on the silicates are of a crystallographic nature, a number of workers have examined their simple Ch. Meycr and J . Bastick, Bull. SOC. chirn. France, 1974, S9. W. Glass and R. A . Ross, J. Phys. C'hem., 1973, 77, 2571. D. D. Hey, G. M. Kiwanuka, and C. H. Rochester, J.C.S. Faraday I , 1973, 69, 2062. 300 M . Iwaizumi, S. Kubota, and T. Isobe, Bull. Chem. SOC.Japan, 1974. 47, 597. "' K. Shimokoshi. Bull. Chem. Soc. Jupun, 1974. 47, 14. '"' S. Kubota, M. Iwaizumi, and T. Isobe, J . Phys. Chem., 1973, 77, 2837. 307 S. Yoshida, T. Matsuzaki, T. Kashiwazaki, K. Mori, and K. l'ararna, Bull. Chem. Soc. Japun, 1973, 47, 15~64. lo' T. Morimoto. J. lmai, and M. Nagao, J. Phys. Chem.. 1974, 78, 704. 2y7

"' R. Lyy

Elements of Group I V 233 chemistry. Complementary investigations of the influence of MCl (M = Li, Na, or K)305and of M2S04(M = Na or K),306MSO, (M = Ca, Mg, or Ni),306 and M,(SO& ( M = A l or Fe)'"" on the kinetics of hydration of tricalcium silicate, Ca3Si0,, have been effected. It is concluded that the presence of the electrolyte accelerates the hydration, the electrolytes influencing the formation of some hydrosilicates of high basicity, their proportion in the hardened binder growing with electrolyte c o n ~ e n t r a t i o n . ~ ~ ~ The spinel phase of forsterite, y-MgSiO,, has been shown to decompose at high pressure (330 kbar) and temperature (1000°C) to the rock-salt structure of MgO (periclase) and the rutile structure of SiO, (stishovite) according to reaction (58)."' y-MgzSiO, + 2Mg0 + SiO,

(58)

The oxidation of natural olivines (Mg,Fe)&O, has been studied as a function of the Mg:Fe ratio.308The results indicate that the reaction occurs in two parts; the initial breakdown of the fayalite component, Fe,SiO,, is followed by reaction of the SiO, so formed with the forsterite component Mg2Si04, to give magnetite and orthopyroxene [reactions (59)-(6 l)]. A compositional control on the oxidation process was also apparent; thus, 3Fe2Si04+ 0, -+2Fe304+ 3si0, 3Mg2Si0, + SiO, + 6MgSi0, 6(Mg,Fe),Si04+ 0, +-2Fe304+ GMgSiO,

(59)

(60) (61)

whereas reaction occurs to a partial or complete extent for fayalitic olivines (63-75% forsterite), no signs of attack were observed for the most forsteritic olivines (85-89% for~terite).~" A preliminary c ~ m m u n i c a t i o ndescribing ~~~ the formation of a new calcium silicate phase (Ca:Si ratio = 0.84) in hydrothermally treated yCa2Si04-SiO, mixtures has been published. The new silicate, which was found mixed with quartz and xonotlite, is monoclinic, with unit-cell parameters a = 12.02, b = 7.42, c = 14.14 A, p = 98". The Na20-SiOz-H,0310 and K,O-SiO,'" systems have been the subject of separate investigations. Crystallization at 90 "C in the former system gave two polysilicate crystalli1H20, zation fields, Naz0,9-16Si02,9-12Hz0 and Na20,8-10SiO2,9-l and the silicates Na2Si03,Na3HSi0,,2H,0, and Na,HSi0,,Hz0.310A study of the second system has shown the existence of two allotropic forms of potassium metasilicate, a - and p -K,Si0,.31' The compound with the highest

'"'I. Teoreanu "I6

'07 '08 30Y

''" ''I

and M. Muntrean, Rev. Rournaine Chim., 1974, 19, 37 1. A. V. Usherov-Marshak and A. M. Urzhenko, Russ. J. Phys. Chern., 1973, 47, 1167. M. Kumazawa, H. Sawamoto, E. Ohtani, and K. Masaki, Nature, 1974, 247, 356. A. D. T. Goode, Nature, 1974, 248, 500. A. Bezjak, I . Jelenik, and J. Jernejkit, Nature, 1974, 248, 581. V. G. ll'in, N. V. Turutina, K. B. Kazakov, and V. M. Bzhezovskii, Doklady Chem., 1973, 209, 296. A. Bon and C. Gleitzer, Compt. rend., 1973, 277, C , 1 1 09.

Inorganic Chemistry of the Main -group Elements 234 alkali-metal content obtained was the pyrosilicate &Si207 (isostructural with K,Co,07); K,SiO, was not observed. A number of silicate and germanate fluoroamphiboles of the richterite series, Na2Mg2[(Si,,Ge,-,)022]F2 (n = 8, 7.7, 4, o r 0), in which the anions form a ribbon structure, have been synthesized and their properties studied as a function of Si-Ge content;312it is concluded from the data that a broad chemical crystallographic analogy exists between the silicates and germanates. The intercalate chemistry of the layer lattice silicates montmorillonite {M0+s(A13sMgo ,)[Si,02,1(OH)4>”’ and hectorite {Na, ~ ( M g34Lifl s 66)[Si,Om](OH,F)4}”4has been studied by two groups of authors. Thomas et al.”’ have discovered an easy conversion, which occurs in the solid state, of the 4,4’diaminostilbene intercalate of montmorillonite; the amine, which is thought to be intercalated as a doubly charged diprotonated species [ H , N C 6 ~ C H = C H C 6 H 4 N H 3 ] 2 tforms , aniline on heating. Pinnavaia and Mortland3I4have continued their investigations of the adsorption of aromatic molecules o n the intracrystal surfaces of these minerals; benzene, toluene, anisole, and thiophen, adsorbed o n Fe1I1and V 0 2 +exchange forms of hectorite, were studied by i r . , u.v.-visible, and e.s.r. spectroscopies. In addition to aromatic radical cation formation, Type I1 complexes, which exhibit distortion of the arene ring and a loss of aromaticity, were formed with ( a ) benzene on the FeIrl exchange forms and ( b ) anisole and thiophen o n both FeIrr and V 0 2 +exchange forms. These complexes are identical to those previously observed on CuI’ layer lattice silicates. It is suggested that the type I1 complexes are associated radical cations formed by electron transfer from the parent molecule to the metal ion. Toluene radical cation formation is accompanied by and inhibited by polymeri~ation.”~ The existence of a new silicate species in the Me,NOH-SO,-H,O system has been reported ;31 tetrame thylammonium tricyclo hep tasilicate, (Me,N),,[Si,O,,],aq., has been characterized by chromatographic and kinetic methods and by mass spectrometry. The corresponding trimethyisilyl ester, (Me,Si),,[Si,O,,], has also been isolated. Interest in both liquid-state and solution chemistry of the silicates has been maintained during the period of this Report. Esin has carried out theoretical analyses of the stability of and the distribution317 of and p ~ l y m e r i z a t i o n ”of ~ anions in silicate melts. The incongruent melting of many silicates has been explained in terms of the distribution and composition of silicate The densities of melts in the systems ’I7

711

114 ’Is

’Ih ’I7 qix

L. F. Grigor’eca, Z . V . Krupenikova. a n d D. P. Komanoc, D o k l u d y <’hem., 1973, 213, 915. I). 1’. H . Tenakoon. .I. M. Thomas. M . J . Tricker. arid S. H. Graham. J.C.S. Chern. Cumm., 1974, 124. T . .I. Pinnavaia, P. L. Hall, S . S. Cady, and M . M . Mortlanti, J. Phys. Chem.. 1974, 78, 994. D. Hocbbci a n d W. Wieker, Z . unorg. Chem., 1974. 405, 267. 0. A. Esin, Russ. J. Phys. Chem., 1973, 47, 1188. 0. A . Esin, Russ. J. Phys. Chem., 1973, 47, 1189. 0. A. Esin, Dokludy Chem., 1973, 211, 561.

Elements of Group IV

235

CaO-SiO,, CaO-FeO, and FeO-SiO, and in ternary melts containing fixed amounts of SiO, have been measured from the liquidus temperature to 1600"C.319Interpretation of the data has shown that the degree of silicate anion polymerization is greater in iron silicate melts than in the corresponding calcium silicates. Preferred ionic association in the ternary systems occurs between Ca2' and the silicate ions and between Fe" and free oxygen ions. The presence of a variety of polymeric silicates, including branched-chain species, in aqueous silicate solutions has been shown by two independent 29 Si n.m.r. The results are in direct conflict with earlier data on aqueous Na,Si03 solutions, which indicate that the silicate species is entirely monomeric, but agree with recent Raman spectroscopic and trimethylsilylation studies. Car' and Mg" complexes of partially deprotonated KSiO, have been investigated at 25 "C in solutions of constant C10; molarity (M) by computer-controlled coulometric titration using a hydrogen The experimental data could be explained assuming equilibria (62)-(64). The dissolution of synthesized diopside CaMg[SiO,], and a glassy material of the same composition in acid solution has been i n v e ~ t i g a t e dWhereas .~~~

Mz++ H,SiO; M"

e MH,SiO: + 2H3SiO; e M(H,SiO,),

M2++ H,SiO:-

MH,SiO,

(62) (63) (64)

dissolution of the glass gave rise to equivalent concentrations of Mg" and Ca'' in solution, an essential feature of the diopside dissolution is that the CaII ions are more readily removed from the crystal than are the Mg" ions. Although the cation dissolution rates are not influenced by HCl and HClO, concentrations, that of H2SO4 does have an influence.323 The crystal structures of many silicates of varying complexity have been either determined for the first time or refined during the period of this Report; following the pattern previously adopted, the data will be considered in order of decreasing 0 : S i ratio. Three papers of general interest have been published which are pertinent to this section. They describe (i) an analysis of atomic vibrations and thermal expansion of silicates at high temperature,324(ii) the use of magnetic hyperfine splitting to determine FeII:Fe"' ratios in complex silicate minerals,325and (iii) a method for the refractometric determination of the metal co-ordination number in structures of the Groups I and I1 metal ""

""

'*'

322 327 324 325 726

Y. E. Lee and D. K. Gaskell, Metallurg Trans., 1974, 5, 853. H. C. Marsmann, Z . Naturforsch., 1974, 29b, 495. R. 0. Gould, B. M . Lowe, and N. A. MacGilp, J.C.S. Chern. Cornm., 1974, 720. P. H. Santschi and P. W. Schindler, J.C.S. Dalton, 1974, 181. I. Sanemasa and T. Katsura, Bull. Chem. SOC.Japan, 1973, 46, 3416. S. Deganello, Z . Krist., 1974, 139, 297, R. J . Borg, D. Y. F. Lai, and I. Y. Borg, Nature Phys. Sci., 1973, 246, 46. I. A. Poroshina, A. S. Berger, and S. S. Batsanov, J. Struct. Chern., 1973, 14, 789.

236

Inorganic Chemistry of the Main-group Elements

A complete X-ray study of langbanite has been carried The structure (unit cell parameters are quoted in Table 17) has been used to redetermine the chemical formula, Mn$+Mn:+(MnZ+,Caz+){Mn4+(Fe3+,Sb”)}[Siz022]. It was impossible to establish more closely the type and degree of cation substitution without exact chemical analysis. The crystal structures of Ag6(S04)[Si04],328 Ca,(SO,)[SiO,],”’ (isostructural with the mineral silicocanotite), and 3P,0,,SSi0,33* [isostructural with Ge,O(P0,),,(3P20,,SGeO2)]have been determined; their unit-cell parameters are summarized in Table 17. The crystal structure of Ag,(S0,)[Si04]’2R

Table 17 Unit-cell parameters/A of langbanite, Ag,(SO,)[SiO,], [SiO&, and 3P20,,5Si0, Compound langbanite Aga(SO,)(SiO,) Ca,(SO,)(SiO,), 3P,OS,5SiO,

Symmetry hexagonal tetragonal orthorhombic hexagonal

a 6.77(2) 7.060 10.182 7.86

Cas(S04)

b

c

-

11.12(3) 17.660 6.850 24.13

15.398 -

Ref. 327 328 329 330

shows a new type in which the tetrahedral SO, and SiO, groups are distinguishable; that of 3P20,,5SiO2”” consists of isolated [SO6] octahedra and [Si,O,] groups linked by PO, tetrahedra to form a three-dimensional network. The polymorphism of Li,XO, ( X = Si, G e, o r Ti) has been examined;331all three phases are isostructural (monoclinic) above 700-750 “C but undergo phase transitions o n cooling. A t lower temperatures, only Li,GeO, and Li,TiO, are isostructural (orthorhombic), Li,SiO, adopting a modified monoclinic structure. Phase relationships in the ternary system Li,SiO,Li,GeO,-Li,TiO, have also been established.331The unit-cell parameters of the two crystalline modifications of Li,SiO, are collected in Table 18 and are

Table 18 Unit-cell parameters of Li,SiO, and leucophoenicite Compound LiSiO, (25 “C) Li,SiO, (SOOO C) leucophoenicite

a/A 5.16(2) 5.23(2) 10.842(19)

blA 6.12(2) 6.32(2) 3.826(6)

CIA 5.30(2) 5.45(2) 11.323(9)

PI” 90.1(1) 90.8(1) 103.93(9)

Ref. 331 331 332

compared with those of monoclinic leucophoenicite, Mn,[Si0,J2{1SiO4](OH),}, the structure of which has recently been discussed by Belov et al.”’ In a theoretical analysis of the structure of NizSi0,333it has been shown that the charge densities of t h e Ni atom are deformed in an octahedral crystal 377 V. G. Kau and E. N . Kurkutova. Sociur Phyr. C‘rysf.. 1973. 18, 3 2 0 . m H.-I.. Kcllcr and H. Mullcr-Buschbaum, Z. anorg. Chem., 1974, 408, 205.

’*’

”‘’ -”I 332 333

P. D. Brotherton, J . M. Epstein, M. W . Price, and A . H. White, Austral. .I. (’hem., 1974. 27, 657. H. Mayer, Monatsh.. 1974, 105, 46. B. L. Dubey a n d A. R. West, J . Inorg. Nucleur Chem., 1973, 35, 3713. E. L. Belokoneva, M. A. Sirnonov, and N. V. Belov, Souiet Phys. Cryst., 1974, 18, 800. F. Marumo, M. Isobe, Y. Saito, 7.Yagi, and S. Akimoto, A m Cryst., 1974, B30, 1904.

Elements of Group IV

237

field; residual electron densities were also observed between Si and 0 atoms. E.s.r. of single crystals of ZrSiO, have shown the presence of SiO;, SiO;-, and Si0:- radicals in the crystal structure. It is thought that their formation is due to intrinsic defects in the structure (Zr and 0 vacancies and non-isovalent impurities.) The crystal structures of the related hydrosilicates Na3HSi0,,5Hz0335and CaNaHSi0,3"6."7 have been determined; CaNaHSiO, crystallizes with both and m o n ~ c l i n i csymmetry. ~~~ The unit-cell o r t h o r h o m b i ~(cf. ~ ~ Na,HSiO,) ~ dimensions of all three structures are summarized in Table 19. The positions of the H atoms in Na,HSiO, were determined and the silicon-oxygen

Table 19 Unit-cell parameters of Na,HSiO, and CaNaHSiO, Compound Na3HSi0, CaNaHSiO, CaNaHSiO,

Symmetry

alA

blA

orthorhombic orthorhombic monoclinic

11.78 5.71 5.72

10.94 9.18 7.06

CIA

12.96 7.03 5.48

pl"

-

122.5

Ref. 335 336 337

tetrahedra were shown to be linked in pairs by hydrogen bonds to form groups with the composition Si,0,(OH),.335 Monoclinic CaNaHSiO, has a structure based on Ca2+ and Na+ cations and HSi0:- groups which are linked into chains by strong hydrogen the structure is similar to that of the orthorhombic form, from which it differs in the orientation of the silicon-oxygen tetrahedra and the arrangement of the hydrogen A detailed analysis of the structural modifications of erbium pyrosilicate, Er,Si,O,, has been ~ n d e r t a k e n . ~It~exists ' in three modifications [equilibrium (65)]. The triclinic phase is pyrosilicate in composition only, since it contains [Si,Olo] groups and isolated [SiO,] tetrahedra. Both the lowertemperature monoclinic (1) modification, which is isostructural with thortveitite, Sc,Si,O,, and the higher-temperature monoclinic 42) modification are true pyrosilicates containing the [Si,O,T- group. The major difference in these structures is that monoclinic (1) contains neighbouring rows of pyrogroups that are parallel to each other, whereas in monoclinic (2) they are rotated with respect to each other by ca. 60". The structural mechanism of the phase transition between the two monoclinic phases has also been elucidated .338 triclinic

10.50 "C

monoclinic (1)

=monoclinic (2) 1400 "C

(65)

A .57FeMossbauer study of the mineral deerite, Fe~~Fe~'[Si,20,0](OH)lo, has been effected over a wide temperature range (5-500 K).339The spectra

"'V. P. Solntsev, M. Ya. Shcherbakova, and E. V. Dvornikov, J. Struct. Chem., 1974, 15, 201. 333 336

337

338 339

Yu. I. Srnolin; Yu. F. Shepelev, and I. K. Butikova, Soviet. Phys. Cryst., 1973, 18, 173. V. I. Lyutin, E. A . Kuz'rnin, V. V. Ilyukhin, and N. V. Belov, Soviet Phys. Cryst., 1974, 19, 33. B. G. Cooksley and H. F. W. Taylor, Acta Cryst., 1974, B30, 864. Yu. 1. Smolin and Yu. F. Shepelev, Soviet Phys. Cryst., 1973, 18, 390. E. Frank and D. St. P. Bunbury, J. Inorg. Nuclear Chern., 1974, 36, 1725.

238

Inorganic Chemistry of the Main -group Elements have been resolved into contributions from three types of site, one Fe3+and two Fe2', probably all with distorted octahedral symmetry. The results do not support an earlier suggestion that deerite might contain low-spin Fe. It is, however, found to show antiferromagnetic ordering, with a Nee1 temperature of 58k6 K. Hawthorne and G r ~ n d y ~ "have ~ , ~ refined "~ the unit-cell parameters of the pyroxenes NaXSi206 (X = ScT40or In3"l) and have shown that the variation of the monoclinic cell dimensions (a sin p, b, and c ) across the pyroxene series NaXSi206(X = Al, Fe, Sc, or In) is linear with respect to the radius of the M1 site cation (X). NaInSi'O, is a slight exception (its cell volume is smaller than expected), probably owing to the constraints applied by the M2 site cations and elements of the tetrahedral chain on the rate of increase of the a sin /3 and c dimensions.341The unit-cell parameters of these pyroxenes are compared to those of the related monochic phases Na2BaSiz06342and la bunt sovit e , (K,Ba ,Na ,Ca), (Ti,Nb),( 0,OH),,[ Si40 2]4, n H,O ,343 in Table 20. Table 20 Monoclinic unit-cell parameters of NaXSi20, (X = Sc or In), Na2BaSi206, and labuntsovite

Compound NaScSi,O, NaInSi,O, Na,BaSi,O, labuntsovite

Space group C2/c C2/c P2, 12/m

alA

blA

CIA

Pl"

Ref.

9.8438(4) 9.9023(4) 11.440(3) 14.18

9.0439(4) 9.1307(4) 4.758(2) 15.48

5.3540(2) 5.3589(2) 5.670(2) 13.70

107.215(2) 107.200(1) 91.42(4) 117

340 341 342 343

The structure of the pyroxene Na,BaSi206 as described by Dent Glasser et a1.342is shown in Figure 4. It contains infinite chains parallel to b and linked through five- and six-co-ordinate Na+ and eight-co-ordinate Ba". Comparison with the related structures of BaGeO, and Na,SiO, shows that Na2BaSi206 can be regarded as being composed of alternate slices of high-temperature BaSiO, (assuming this to be isostructural with hightemperature BaGeO,) and Na2Si03;this feature is also shown in Figure 4.'"' Single-crystal vibrational spectra of beryl, Be,Al2Si,O,,, and dioptase, Cu6Si,0,,,6H,0, have been determined.344Although the same [Si601s]"~ ring occurs in both minerals, slight distortions, caused by the need to provide Cu2+with a tetragonal environment, have a profound effect on the spectrum of dioptase, which bears little resemblance to that of beryl. Nevertheless, almost the full number of bands predicted by factor-group analysis have been observed in each The structure of vlasovite, Na,ZrSi4011, which was previously thought to contain a novel and, as yet, unique [Si40,1]6-strip anion, has been checked ~

W' F. C. Hawthorne and H.

1).Grundy, Actu C r y s t . , 1973, B29, 2615. Hawthorne and H. D. Grundy. Actu Cryst., 1974. B30, 18x2. R. P . Gunawardane, M. E. Cradwick, and L. S. Dent Glasser, J.C.S. Dalton, 1973, 2397. N . I . Gdovastikov, Sovief Phys. Cryst., 1974, 18, 596. D. M . Adarns and I. R. Gardncr. J.C.S. Dalton, 1974, 1502.

'" F. C. '42

"' 344

Elements of Group IV

239

Figure 4 The structure of Na,BaSi,O,; the true unit cell is indicated by full lines. Large circles indicate Ba atoms, small circles Na atoms. Heavy and light triangles, and filled and open circles indicate, respectively, tetrahedra and cations separated by half a cell repeat perpendicular to the paper. (Reproduced from J.C.S. Dalton, 1973, 2397) and refined.345It is concluded that vlasovite belongs to a structural chemical group of alkali zirconosilicates. A primary characteristic of these materials, of which there are many examples, is the fact that they contain a threedimensional ‘heterogeneous’ or ‘mixed’ framework. The latter is created by Zr octahedra and Si tetrahedra in such a way that each 0 atom of the structure simultaneously belongs to two of the framework polyhedra. In this kind of structure, each Zr atom has three (6 x i ) and each Si atom two (4X $) oxygen atoms. Hence the general empirical formula of the framework Corresponding compounds containing may be written as (Zr,O,, Sin02n)Zm-. (e.g. alkali-metal cations M (e.g. vlasovite) are M,,Zr,Si,O,,,,,

Na2ZrSi401J.345 The structural formula of a synthetic Mg’” mica has been refined as K2.00(Mg5.60~o,4,)[(si,.,,Mg,.,,)0,,l(OH)4 from the results of a determination of its crystal This mica is intermediate between the trioctahedral and dioctahedral types and agrees with a Mg-rich mica first reported by Seifert

’45

A. A. Voronkov, T. A. Zhdanova, and Yu. A. Pyatenko, Soviet Phys. Crysr., 1974, 19, 152.

340

H. Tateyama, S. Shimoda, and T. Sudo, Z . Krist., 1974, 139, 196.

Inorganic Chemistry of the Main- group Elements 240 and S ~ h r e y e r . ~The , ~ crystal structure of the high-temperature form of Ba,[Si,Olo] has also been dete~rnined.~,, Finally, synthetic K,[Si,O,,] has been the subject of two complementary s t u d i e ~ . ~It~ is ~ ,triclinic, ~” space group P i , with a = 12.32(2), b = 4.943(1), c = 8.369(1) A, a = 90.80(2)”, p = 111.19(1)’, y = 89.69(1)”, and Z = 1.””’ The geometrical structure of the anion is based o n [Si,O,] single chains with two tetrahedra in the identity period parallel to (010). Pairs of chains are joined via all the tetrahedra to form double chains of [Si,O,,]. These double chains are connected to form single layers of [Si,O,,]; K,[Si,O,,] is therefore the first example of a new scheme of condensation of [SiO,] tetrahedra.349 Germanium(rv), Tin(rv), and Lead(rv) Oxides, and Related Germanates and Stannates.-The principal products from the co-condensation of germanium vapour with excess krypton containing a few mole per cent 0, at 16 K are ozone and GeO, but in nitrogen matrices significant concentrations of molecular GeO, are also formed. Normal-co-ordinate analysis shows that the latter molecule is linear, with a principal Ge-0 stretching force constant of 7.32 mdyn k’. Oxygen isotope distribution experiments show that GeO, is formed by the insertion of G e atoms into the 0-0 bond, whilst 0, is formed by the end-on addition of ground-state 3P oxygen atoms to 0,.3” The conversion of hexagonal GeO, into the tetragonal modification is catalysed by a number of alkali-metal germ an ate^.^^^^^^^ The composition of a-stannic acid that has been dried just over silica gel for five days is best represented by the composition Sn02,4H20, but it is converted into xSnO,,xH,O on more drastic deh~dration.~’, The thermal behaviours of a and p-PbO, of different specific surface areas have been studied. The ultimate product in all cases is ( Y - P ~ O . ~ ’ ~ Germanium 4d -orbital contribution to the electronic structure of GeO: and Ge0:- has been estimated from LCAO-SCF c a l c ~ I a t i o n s Li,SiO,, .~~~ Li,GeO,, and LbTiO, are isostructural above 700-750 “C, but undergo phase transformations o n cooling. At lower temperatures only Li,GeO, and Li,TiO, are i ~ o s t r u c t u r a lPhases . ~ ~ ~ of the composition Ba(Si,-,Ge,)Os (0 S x s 0.625) have been synthesized by heating mixtures of initial composition BaC0,,(4 - x)SiO,,xGeO, at 1130 O C 3 ” A new single-crystal antimony F. Seifert and W. Scheyer, Contrih. Miner. Petrogr., 197 1. 30, 1 Y6. H. Katscher, G. Bissert, and F. Liebau, Z. Krist., 1973. 137, 146. H.Schweinsberg and F. Liebau, Acta Cryst.. 1974, B30, 2206. S. Durovit, Acta Cryst., 1974, B30, 2214. 7 5 1 A. Box, J . S. Ogden, and L. Ogree, J. Phys. Chem., 1974, 78, 1763. M. Yonernura and Y. Kotera, Bull. Cham. Soc. Japan, 1974, 47, 789. 35 7 M. Yonemura and Y. Kotera, Bull. Chem. SOC.Japun, 1974. 47, 793. ”‘ S. Durand and E. Masdupuy, Bull. Soc. chinz. France, 1974, 1844. 755 P. Bussiere and D. Weigel, J. Inorg. Nuctear Chern., 1974. 36, 463. ”‘ B. F. Shchegolev and M. E. Dyatkina, J . Struct. Chern.. 1971. 15, 302. ’“ B. L. Dubry and A. R. West. J . Inorg. Nuclear Cham., 1973, 35, 3713. 358 M. Goreaud, J. Choisnet;B. Raveau, a n d A. Deschanvres, Rev. Chim. minerale, 1974, 11, 207.

-347

348

’”

Elements of Croup IV

241

germanate, Sb,Ge,07, has been isolated by crystallization in the Ge0,Sb,O,-KF-H,O Eight phases have been revealed by X-ray studies in the CdO-GeOz-H,O, CdO-Ge0,-NaOH-H,O, and CdO-Ge0,NaCl-H,O systems, which have been identified as CdrGe04, CdzGezO6, Cd,GeO,(OH),, Cd9Ge40,6(OH)2,NaCd2Ge308(0H),NaCd4Ge5Ol4(0H), CdGe,O,, and Cd,Ge,0s.360Four phases, K,Zr,Ge,O,, K3ZrF7, K2Ge409, and baddeleyite ZrO,, have been isolated from hydro thermal crystallization in the ZrO,-GeO,-KF-H,O No solid solution could be found on the GeCozO, side of the CoA1,04-GeCo204 system, but a large range of solubility exists on the CoA1,04 side. With increase of Ge4+in the solid solution, the number of Co2+ions in the tetrahedral sites decreases very The rapidly, and that of A13+increases at first but then also crystal structure of NaHCd,(Ge,O,) has been determined. Anionic (Ge309)chains extend along the b-axis. The mean Ge-0 bond distances in the three GeO, tetrahedra are 1.74, 1.78, and 1.72 A, respectively.363Rareearth stannates, Ln,(SnO,),,xH,O, have been obtained from the systems LnC1,-Na,SnO,-H,O (Ln=La, Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, Yb, Lu, or Y). At temperatures of 700-900°C, they decompose into the corresponding distannates, Ln,Sn,O,, which may also be prepared by the coprecipitation from solution of lanthanide and tin hydroxides with ammonia followed by heat treatment of the mixture at 900°C.364Coprecipitated Sn0,-CuO gels, particularly those having a Cu:Sn atomic ratio of 0.5-0.6:1, exhibit high activity for the catalytic reduction of NO by CO after thermal activation at 450 0C.365Similar high activity for the reduction of NO by CO, H,, and C2H4 is shown by SnO, catalysts containing between 0.1 and 5% C I - ~ O , . ~ ~ ~

Molecular Silicon(rv)-, Germanium(1v)-, Tin(rv)-, and Lead(1v)-Oxygen Compounds.-Oxides. The photoelectron spectrum of H,SiOSiH, has been assigned and correlated on the basis of CND0/2-SCF-M0 calculations.367 The SiOSi skeleton in hexachlorodisiloxane has been confirmed to be bent Dipolefrom a more accurate interpretation of the vibrational moments studies have shown that the SiOE valence angle in R:SiOR’ and R:SiOSiR: compounds may vary on a wide scale according to the nature of 3s9

( ‘’)

”’ ‘02

363

3h4

365

3’7

”’

M. N. Tseitlin, G. F. Plakhov, A. N. Lobachev, V. I. Popolitov. M. A. Simonov, and N. V. Belov, Soviet Phys. Cryst., 1974, 18, 525. E. L. Belokoneva, M. A. Simonov, N. G. Duderov, A. N . Lobachev, and N. V. Belov, Soviet Phys. Cryst., 1974, 18, 610. N . A. Nosyrev, L. N . Dem’yanets, V. V. Ilyukhin, and N. V. Belov, Soviet Phys. Cryst., 1974, 19, 27 1. H. Furuhashi, M. Inagaki, and S. Naka, J. Inorg. Nuclear Chem., 1973, 35, 3707. E. L. Belokoneva, P. A. Sandomirskii, M. A. Simonov, and N. V. Belov, Soviet Phys. Cryst., 1974. 19, 94. G. G. Mel’chenko and V. V. Screbrennikov, Russ. J. Inorg. Chem., 1973, 18, 618. M. J. Fuller and M. E. Warwick, J.C.S. Chem. Cornm., 1974, 57. F. Solymosi a n d J. Kiss, J.C.S. Chem. Cornm., 1974, 509. H. Bock, P. Mollere, G. Becker, and G. Fritz, J. Organometallic Chem., 1973, 61, 113. J. E. Griffiths, Spectrochim. Acta, 1974, 30A, 945.

242

Inorganic Chemistry of the Main -group Elements 26

I4

n

Figure 5 The structure of 1,1,2,2-tetrarnethyl-3,3,4,4-tetraphenylcyclotetra siloxane (Reproduced by permission of the Consultants Bureau, New York, from J. Struct. Chem., 1973, 14, 639) the groups bonded to silicon. The moments of the R:Si-O groups are constant (1.10f0.05 D in benzene and 1.03f 0.05 D in dioxan) whatever R' may be.369 1,1,2,2-Tetramethyl-3,3,4,4-tetraphenylcyclotetrasiloxane possesses the 'bath' structure, with r(Si-0) = 1.62, r(Si-C) = 1.84 A, LSiOSi = 148.5",and LOSiO = 1 11 (Figure 5)."" Carboxylic acids cleave ally1 groups from dibutyldiallyltin in moist methanol or acetone-water to afford tetrabutyl-l,3-diacyloxydistannoxanes (RCOO)Bu,SnOSnBu,(OOCR) and/or the corresponding 1-acyloxy-3hydroxydistannoxanes (RCOO)Bu,SnOSnBu,(OH).37'Mossbauer and vibrational spectra indicate that (Me,Sn),Sn(OH)N, has a structure in which O

-Ih"

'"' "'

M . Bordeau, .I. Dedier, E. F;rainnet. J . P. Fayet, and P. Mauret, J. Organometallic ChrJtn.. 1973, 59, 125. V. E. Shklover. A . E. Kalinin, A. 1. Gusev, N. G. Bokii, Yu. T. Struchkov. K. A . Andrianov. and 1. M . Petrova, J. Struct. Chem., 1973, 14, 639. V. Peruzzo and Cr. Tagliavini, .J. Organometallic Chem.. 1973, 66, 437.

Elements of Group I V 243 planar Me,Sn units are bridged by OH and N, (through the a - N atom) groups to give infinite chains. Adjacent chains are linked by hydrogenbonding of the OH groups and the y-N atoms of the azido-groups. The tristannoxane [N,Me,Sn(OSnMez),N,], is assumed to be dimeric, containing five-co-ordinate trigonal-bipyramidal tin atoms arising from cross-linking through the oxygen atoms and two bridging a ~ i d o - g r o u p s Chloroethyl.~~~ distannoxanes react with lactones with ring opening to yield R,SnO(CH,),COOSnR, compounds. Rate studies show the order of reactivity to be C1,EtSnOSnEt,Cl> Et,SnOSnEt, > ClEt,SnOSnEt, > C1Et,SnOSnEt,C1.373 Several papers relate to mixed metalloxanes. Hexa-alkylgermastannoxanes R,GeOSnR, are readily obtained by heating mixtures of the symmetrical oxides. The compounds undergo facile reactions with isocyanates and chloral, presumably at the Sn-0 bond, to give the expected metal-substituted carbarnates and acetals .374 The platinum siloxane cis (R,P),Pt(OSiMe,), and iridium siloxanes trans -(R,P),Ir(CO)OSiMe,, but not the analogous palladium siloxanes, have been synthesized from NaOSiMe, and appropriate metal chloride complexes.375This method has also been used to obtain the siloxy-iron derivatives [(R,SiO),Fe], (dimeric via siloxy bridges), (Me,SiO),Fe,OPMe,, and Na[Fe(OSiMe,),]. Magnetic measurements show that a weak antiferromagnetic Fe-Fe interaction occurs in the dimeric compound, but the mononuclear compounds show simple spinonly values.376 Hexamethyldisilazane reacts with VOCl, to form (Me3SiO),V=NSiMe3.”’ N.q.r. spectra of the silyl and germyl perrhenates Me,MOReO, (M = Si or Ge) indicate true covalent bonding between M and the perrhenate anion. All Re atoms are equivalent in the Dialkyl(triphenylsi1oxy)aluminium compounds undergo rearrangement involving exchange of phenyl and alkyl between aluminium and silicon at temperatures in excess of 250°C.37’ A number of silyl-, germyl-, and stannyl-borates have been made by a variety of routes, e.g. as shown in reactions (66)-(69).380-383 Alkoxides and Related Derivatives. The structures of two five-co-ordinate and silicon compounds have been determined, p - 1-phenyl~ilatrane~’~ [iminobis(ethyleneoxy)]diphenylsilane.385 Two crystalline modifications of N. Bertazzi, G. Alonzo, R. Barbieri, and R. Herber, J. Organometallic C’hem., IY74, 65, 23. S. Sakai, Y. Kiyohara, M. Ogura, and Y. Ishii, J. Organometallic Chem., 1974, 72, 93. -374 S. K. Mehrotra, G. Srivastava, and R. C. Mehrotra. Indian J. Chem.. 1974, 12, 62Y. 3 7 5 H. Schmidbaur and J . Adlkofer, Chem. Ber., 1974, 107,3680. 2 7 h H.Schmidbaur and W. Richter, Chem. Rer., 1974, 107, 2427. 377 A. P. Shihada, Z . anorg. Chem., 1974, 408, 9. 37x H. Schmidbaur, D. Koth, and P. K. Burkert. Chem. Ber., 1Y74, 107,2697. 379 G.A. Razuvaev, I. V. Lomikova, L. P. Stepovik, and T. T. Karabanova, J . Gen. Chem. (U.S.S.R.),1973, 43, 2396. ”” A. B. Goel and V. D. Gupta, J. Organometallic Chem., 1974, 77, 183. 3 R 1 S. K. Mehrotra, G. Srivastava, and R. C. Mehrotra, J. Organometallic Chem., 1974,65, 361. 3xz S. K. Mehrotra, G. Srivastava, and R . C. Mehrotra, J. Organometallic Chem., 1974, 65, 367. ’’’ S. K. Mehrotra, G . Srivastava, and R. C. Mehrotra, J. Organometallic Chem., 1973, 54, 139. -’*‘ L. Parkanyi, K. Simon, and J. Nagy, Acta Cryst., 1974, B30, 2328. ”‘ J. J . Daly, J.C.S. Dalton, 1974, 205 1. ‘72

373

Inorganic Chemistry of the Main-group Elements

244 N'O\

11

RC,N" H

B-0-€3

P" 11

\"CR H

+ H,O

+2Me3SiC1+2Et,N

-

N ' q

2 I! BOSiMe, + 2Et,NHCl RC .N' H

-11 RC+

BOH

+ Bu,SnCl + N E t ,

H

NOH

(Bu,Sn),O

2B(OH),

+ 2B(OH), + 2RC/

+ 3(R,Sn),O

ro\ BONa + R,MCI

E

Ld

1 NH0, II BOSnBu, /

RC".

(66)""

(67)"'

H

\

__+

2(R,SnO),B

+ 3H,O

- rO\ E

BOMR, + N a C l 0'

E = CMe,CH,CHMe, CMe,CMe,, or CHMeCH,; M = Ge or Sn

the former compound have been reported, an orthorhombic p-form and a monoclinic y-form. The structure of the p-form is shown in Figure 6. The nitrogen atom co-ordinates to the silicon [r(Si-N) = 2.156 A], completing trigonal-bipyramidal co-ordination [r(Si-0) = 1.657 A; LNSiC = 177.0'; LOSiO = 83.3, 96.8, 118.6°].384The co-ordination at silicon is very similar in [iminobis(ethyleneoxy)]diphenylsilane (Figure 7), with phenyl groups occupying one each of the equatorial and axial positions [r(Sn-C) = 1.886, 1.901 A], the nitrogen the other axial site [r(Sn-N)= 2.301 A], and the two oxygens in the remaining equatorial sites [r(Si-0) = 1.652 A]; LCSiN = 174.0', LCSiC= 101.0', LCSiO = 95.8, Trimethyltin methoxide also contains trigonal-bipyramidally co-ordinated Group IV metal. Crystals consist of infinite chains of planar trimethyltin units bridged by methoxy-groups (Figure 8). The 0-Sn-0 unit is almost lineBr (172.4'), but the chains are bent at oxygen (LSnOSn = 131.2'); r(Sn-C) = 2.14, r(Sn-0) = 2.23 A.3Rh The structures of organotin alkoxides in solution have been investigated using 'H and '19Sn n.m.r. Trimethyltin alkoxides appear to be tetrahedral and monomeric, but dimethyltin dialkoxides and methyltin trialkoxides are associated in The equilibria between Gel" and ortho -diphenols in aqueous media have been studied p o t e n t i ~ m e t r i c a l l y . ~ ~ ~ IKh 387 IXX

A . M . Dorningos arid G. M . Sheidrich, Actu Cryst., 1974. B30, 519. E. V. van den Berghe and G. P. van der Kelen, J. Mol. Structure, 1974, 20, 147. V Stejskal and M . Bartusek. Coll. Czech. Chem. f o m m . , 1973, 38, 3103.

245

Elements of Group IV

C(15)

Figure 6 T h e structure of p-1-phenylsilatrane (Reproduced by permission from Acta Cryst., 1974, B30, 2328)

The U.V. spectra of tri- and di-organo(oxinato)-silanes and -germanes indicate that the oxinate ligands may be chelating or non-chelating according to the number and nature of the organic groups on the metal atom.389 Tin- 1 19rn Mossbauer spectroscopy has been employed to deduce the structures of several organotin oxines. In all cases the oxine functions as a

t c, 7

1

11

Figure 7 The structure of [irnirtobis (ethyleneoxy)]diphenylsilane (Reproduced from J.C.S. Dalton, 1974, 2051) 3*9

M. Wada, T. Suda, and R. Okawara, J . Organometallic Chem., 1974, 65, 335.

246

Inorganic Chemistry of the Main -group Elements (C1

Figure 8 The repeat unit of’ the (Me,SnOMe), chains (Reproduced by permission from Acta Cryst, 1974, B30, 519)

chelating Iigand.’”’ In co-ordinating solvents, dimethyl-leadbis(0xinate) derivatives, but not the corresponding tin compounds, form solvates via co-ordination of the solvent to the lead.,” The tris(acetylacetonato)germanium(iv) ion has been resolved by the crystallization of its hydrogen (R,R)-diben~oyltartrate.~’~ Ligand exchange and racemization of this and the silicon analogue have been studied in a variety of solvents. Exchange is very much slower than racemization, which is thought t o proceed intramolecularly via a five-co-ordinate intermediate in which one of the ligands is ~ n i d e n t a t e .A~ n~ intramolecular ~*~~~ process is also responsible for ligand exchange in the dihalogenobis(acety1acetonato)tin(1v) complexes S n ( a ~ a c ) ~ X( X , = F, C1, Br, o r I). The vibrational spectra suggest that all the complexes possess the cis stereochemistry in both the solid and in Kinetic data show that the intermolecular ligandexchange reaction between diphenyltin and dimethyltin bis(acety1acetonates) is first-order in the former reactant but zero-order in the dimethyltin compound. The rate-controlling step of the proposed mechanism involves tin-oxygen bond fission in Ph,Sn(acac), to produce a five-coordinate species with a dangling unidentate acetylacetonate ligand.”‘ Dimethyltin bis(acety1acetonate) has been subjected to an intensive tin- 1 19m Mossbauer study. Dynamic motion in the solid has been studied in the temperature range 4.2 < T =s 120 K, and results on frozen solutions indicate that major structural differences exist between the solid and the molecule in solution.’Y6The magnitude of the Mossbauer quadrupole splitting has been used

’” 3Y3 3‘24

195 396

J. N. R. Ruddick and J. R . Sams, J.C.S. Dalton, 1973, 170. M. Aritomi and Y. Kawasaki, J. Orgunornetallic Chrrn., 1973. 81, 363. A . Nagasawa a n d K. Saito, Bull. Chern. SOC..lapun, 1974, 47, I3 1 T. Inoue and K. Saito, Bull. Chem. S o c . Japun, 1973, 46, 2417. R . W. Jones and R. C. Fay, lnorg. Chem., 1973. 12, 2599). N. Serpone and R. Ishayek. Inorg. Chent., 1974. 13. 5 2 . R. H. Herber, M. F. Leahy, a n d Y. Hazony, J. Chern. Phys.. 1974. 60, S O 7 0

Elements of Group I V 247 to assign stereochemistry for a large number of tin(rv) bis(acety1acetonate) derivatives. Diphenyltin compounds all have the cis six-coordinate geometry, whilst the dimethyltin compounds all possess the trans structure .397 Several papers relate to structural studies of tin-Schiff -base complexes. In particular, complexes of planar terdentate ligands with O N 0 and SNO donor atoms have been well studied by diffraction and spectroscopic methods. The complexes RClSn(trid) [trid’- being the dianions of the Schiff bases 3-(o-hydroxyphenylamino)crotonophenone (H,bah); N-(2-hydroxypheny1)salicylaldimine (H,sah) ; 4-(2-benzothiazolinyl)pentan-2-one (H,aat) ; and 2-(0 -hydroxyphenyl)benzothiazoline (H’sat)] appear to possess polymeric trigonal-bipyramidal structures, although monomers and oxygenor sulphur-bridged dimers could not be excluded from the data.398Weak oxygen bridging does indeed occur in Me,Sn(sab) [sab = dianion of 2hydroxy-N-(2-hydroxybenzylidene)aniline] (Figure 9).’” Two molecules at

Figure 9 The structure of Me,Sn(sab) (Reproduced by permission from 2. anorg. Chem., 1974, 410, 8 8 ) 397 398

3YY

G. M. Bancroft and T. K . Sham, Canad. J . Chem., 1974,52,1361. L. Pellerito, R . Cefalu, A. Silvcstri, F. Di Bianca, R . Barbieri, H. J . Haupt, 14. Preut, and F. Huber, J. Organometallic Chem., 1974, 78, 101. H. Preut, F. Huber, H. J. Haupt. R. Cefalu. and R. Barbieri, 2. anorg. Chem., 1974,410, 88.

248

Inorganic Chemistry of the Main - group Elements

a time have a centre of symmetry, and individual molecules possess distorted trigonal-bipyramidal geometries with the two methyl groups and nitrogen occupying the equatorial positions [r(Sn-C) = 2.1 17(14)A; r(SnN) = 2.229(11) A; r(Sn-0) = 2.112(9) A; and r(Sn * - * 0)= 2.881(8) A]. Crystals of PhzSn(sat), on the other hand, consist of discrete though heavily distorted trigonal-bipyramidal molecules, in which the phenyl groups and nitrogen again occupy equatorial sites (Figure 10) [r(Sn-S) = 2.496(1);

Figure 10 The structure of Ph,Sn(sat) (Reproduced by permission from 2. anorg. Chem., 1974, 407, 257) r(Sn-0) = 2.093(2); r(Sn-N) = 2.217(3); r(Sn-C) = 2.123(3) A].40"Octahedral configurations for the complexes Sn(trid), and [HNEt,]'[SnCl,(trid)]- have been inferred from spectroscopic data.401Similar diorganotin complexes of quadridentate O N N O Schiff-base ligands derived from salicylaldehyde and diamines have been prepared. Two isomeric forms of Me,Sn(bsed) [bsed = bis(salicyla1dehyde)ethylenedi-iminate]have been isolated in the solid state, which are thought to be cis- (with a bent C-Sn-C moiety and a non-planar bsed ligand) and trans- (with a nearly linear CSn-C moiety and a symmetric bsed ligand) Complexes of the 1iNI

4"1

H. Prcut, H. J . Haupt, F. Huhcr. R. C'efalu. a n d R. Barbieri, Z . a n o r g . C'horn.. 1974. 407, 257. G. C. Stocco, G. Alonzo, A. Silvestri, N. Bertazzi, L. Pellerito, and R. Barbieri, Z . anorg. Chem.. 1973, 409, 2 3 8 . K. Kawakarni, M. Miya-uchi, and T. Tanaka, .I. Organornetullic Chem., 1974, 70, 6 7 .

Elements of Group IV

249

quadridentate ONNO ligand diacetylbisbenzoylhydrazone with Pb", Ph2Pb'", Sn'", and Ph,Sn'" have also been N-Benzoyl-N-phenylhydroxylamineand similar ligands react with silicon tetrachloride to yield cationic complexes of the type (25), containing

(25)

octahedrally co-ordinated silicon.4o4Full details of the crystal structure of Ph,SnONPhCOPh have appeared. The structure is based on a distorted trigonal bipyramid with phenyl groups at one axial site and two equatorial sites, and is thus the only confirmed example of the cis-R,SnX, Mehr~tra'"~has studied the synthesis and reactions of organogermanium oximates in detail. From i.r. data, it was deduced that derivatives with smaller groups exist in the neat liquid as a dimer TI monomer equilibrium. Carboxylates and Oxyacid Derivatives. The structures of two triorganotin carboxylates, Me,SnO,Me and Me,SnO,CCF, (Figure 1l),have been determined. The two compounds are isostructural and are polymeric, with tin atoms linked by carboxylate bridges. The tin atoms enjoy trigonalbipyramidal geometry, with methyl groups occupying equatorial sites and oxygen atoms the axial p o ~ i t i o n s . "The ~ ~ diphenyl-lead perfluorobenzoates Ph2Pb(0,CR), (R = C,F,, p-MeOC6F4, or p-EtOC6F4), obtained from Ph,Pb(O,CMe), and the appropriate acid, also have structures involving bridging bidentate carboxylate groups in the solid state but are monomeric in solution, with chelating carboxylate residues. The thermal decomposition of these compounds involves competing decarboxylation, rearrangement, and (under vacuum) homolysis reactions of the diorganolead biscarboxylates.'O' Tin(1v) chloride is solvolysed in methanesulphonic acid to afford SnCl,(O,SMe),, which forms adducts with bases such as pyridine and b~tylamine."~' Sulphinate derivatives of carbon, germanium, and silicon of the types R,M02SR (M = C, Si, or Ge) have been obtained by the reaction of R,MX (X = C1 or Br) with anhydrous aliphatic or aromatic silver sulphinate. Like the analogous tin and lead compounds they are thought to "'" 404 "05

4nh 407

408

409

R. Cefalu, F. Maddio, L. Pellerito, and V. Romano, Inorg. Nuclear Chem. Letters, 1974, 10, 529. T. Seshadri, J. Inorg. Nuclear Chem., 1974, 36, 519. P. G. Harrison and T. J. King, J.C.S. Dalton, 1974, 2298. A. Singh, A. K. Rai, and R. C. Mehrotra, J . Organornetallic Chem., 1973, 57, 301. H. Chih and B. R . Penfold, J. Cryst. Mol. Structure, 1973, 3, 285. P. G. Cookson, G. B. Deacon, P. W. Felder, and G. J . Farquharson, Austral. J. Chem., 1974, 27, 1895. R. C. Paul, V. P. Kapila, and S. K. Sharrna, Indian J . Chem., 1974, 12,651.

250

Inorganic Chemistry of the Main- group Elements

Figure 11 The repeating unit of the polymeric chain of Me,SnO,CCF, (Reproduced by permission from J. Cryst. Mol. Structure, 1973, 3, 285) possess trigonal-bipyramidal c o n f i g u r a t i o n ~ . ~ The ' ~ synthesis of the tin derivatives by insertion of SO, into the tin-carbon bond of tetraorganostannanes is thought t o proceed through a n open transition state."ll In this reaction (C6FJ4Sn is inert and (CF,=CF),Sn shows only slight reactivity. In the mixed compounds Ph,SnR ( R = C , F , or CF,=CF), only reaction at the Sn-Ph bond takes place, whilst the C6F, group in Me,SnC,F, deactivates the whole molecule towards attack by SO,."" Hexaorganodistannoxanes R,SnOSnR, disproportionate in liquid SO, at and above room temperature to yield diorganotin sulphites, triorganotin sulphinates, and diorganotin disulp hinates ."13 The crystal structure of Si,O[PO,], consists of isolated [SiO,] octahedra and [Si,O,] groups which are linked by [PO,] tetrahedra, forming a threedimensional network. The compound is isotypic with GesO[P0,],."'4 1.r. and Mossbauer data 5uggest that the dichlorophosphate derivatives bridges, Me,+,Sn(02PCI,),, (n = 1 or 2 ) are polymerized through 0-P-0

'"' 'I' 'I2

4'3

"''

E. Lmdner and K. Schardt, J O r g u n o m e t u l l ~C h e m . lY74. 81, 145. U . Kunze and J . D. Koola, J Organometallic Chern.. 1974. 80, 281. J . D. Koola and U. Kunze, J. Organometallic Chem., 1974, 77, 3 2 5 . U . Kunze and H. P. Volker, J . Organometallic Chem., 1973, 66, C43. H. Mayer, Monatsh., 1974, 105, 46.

Elements of Group I V

25 1

leading to five- and six-co-ordinated tin atoms."" Polymeric arylarsonates of general formula BuzSn(O,AsAr), have been ~ r e p a r e d . " ' ~ The structures of several nitrato-derivatives of tin have been inferred from i.r. and Mossbauer data. In simple organotin nitrates the nitrate group functions as a bridging ligand, raising the co-ordination number of tin to five or six. In complexes of tin(iv) nitrate or organotin nitrates with nitrogen donor ligands and the [Sn(NO,),]'- anion, however, the nitrate group is unidentate."" Dimethyltin hydroxide nitrate is dimeric in the solid (Figure 12). Each tin atom has distorted trigonal-bipyramidal geometry, with unidentate nitrate groups in axial sites and the two methyl groups occupying

Figure 12 The structure of the dimethyltin hydroxide nitrate dimer (Reproduced from J.C.S. Dalton, 1974, 475) equatorial positions. The two tin atoms of the dimer are connected by oxygen bridges via the remaining equatorial and axial sites, forming a central four-membered ring.418The structure of tris(trimethy1tin) chromate hydroxide has also been determined and consists of a complex network polymer. Each tin enjoys approximately trigonal-bipyramidal geometry, with approximately planar trimethyltin moieties. Each oxygen atom of the chromate group is bonded to a tin atom, and the hydroxide links adjacent tin

Halides of Silicon, Germanium, Tin, and Lead.-Interest in halide derivatives has been focussed mainly on the synthesis of metal-halogen bonds, structure and bonding, and complex formation. A new method for the 'I5 416

4'7 4'8

4'y

K. Dehnicke, R . Schrnitt, A. F. Shihada. and J. Pebler. Z . anorg. Chem., 1973. 404, 2.19. S. S. Sandhu, J. Kaur, and G . K. Sandhu, Synth. React. Inorg. Merui-Org. Chem., 1974, 4, 437. D. Potts, H. D. Sharrna, A. J. Carty, and A. Walker, Inorg. Chem., 1974, 13, 1205. A. M. Dorningos and G. M. Sheldrick, J.C.S. Dalton, 1974, 475. A. M. Domingos and G. M. Sheldrick, J.C.S. Dalton, 1974, 477.

252

Inorganic Chemistry of the Main-group Elements

preparation of silicon tetrafluoride by the fluorination of silicon tetrachloride with sodium fluoride in acetonitrile has been developed ."'* Several papers relate to the 'direct' synthesis of chlorosilanes. The mechanism of the 'direct' synthesis has been investigated by following the fate of added methyldichlorosilane and toluene in the mixture. Methyldichlorosilane reacts to give Me2SiC1,, MeSiCl,, and small amounts of dimethyltetrachlorodisilane by reaction of the surface of the contact mass. In the presence of toluene, no bibenzyl was formed, but small amounts of ethylbenzene were detected. Both sets of data were interpreted in terms of a chemisorption mechanism.421Preliminary chlorination of the surface of the silicon appears to change its adsorption properties and lowers the temperature of its reaction with methyl chloride. Mechanisms have been proposed for the reaction of methyl chloride on the surface of chlorinated silicon for the cases when the chlorination products are fSi-CI, >Sic],, and -SiC1,.422~423 Thus the mechanism of the direct synthesis is considered as a chain process occurring on the surface of the contact mass and proceeding with the participation of initiators such as chlorine or chlorine donors (e.g. CuCl or HCl). These partially chlorinate the surface, forming active reaction centres to which alkyl halides may chemisorb. Subsequent reaction releases chlorosilane and regenerates the active centre .424 The nature and distribution of metallic impurities in silicon and silicon-copper active masses have been investigated. Iron and calcium are present as FeSi, and CaSi, whereas aluminium is present as a eutectic. FeSi, is distributed at the boundaries of grains of silicon, whilst the aluminium eutectic and CaSi, are localized at the boundaries of the intermetallic FeSi,."" (YO-Dihalogenoalkanes X(CH,),X react with germanium-copper alloys to form the compounds X(CH,),GeX, and X,Ge(CH,),GeX, (X = C1 or Br). Halogenoalkylsilanes react similarly to yield bimetallic compounds with the Si(CH,), G e ~keleton.~"The mechanism of the hydrobromination of silicon and germanium (to give principally HMBr,) has been examined and also is considered to involve the adsorption of an HBr molecule onto an activated reaction centre.427The reaction of elemental tin with alkyl halides in the presence of various catalysts has been investigated and gives rise to dialkyltin dihalides and trialkyltin halides via the intermediate formation of 420 421

423

425

427

D. K. Padma and A . R. '-I. Murthy, J. Fluorine Chem., 1974. 4, 241. J. Joklik and V. Bazant, Coll. Czech. Chem. Comm., 1973, 38, 3176. I. M. Podgornyi, S. A . Golubtsov, K. A . Andrianov, and E. G . Mangalin, J . Gen. Chern. ( U . S . S . R . ) ,1974, 44, 739. I . M . Podgornyi, S. A. Golubtsov, K. A . Andrianov, and E. G . Mangalin, J. Gen. Chem. ( U . S . S . R . ) , 1Y7.1, 44, 745. S . A. Golubtsov. K. A. Andrianov, N. T . Ivanova, R. A. Turetskaya, I. M. Podgornyi, and N . S. Fel'dshtein, J. Gen. Chem. (U.S.S.R.), 1973, 43, 1Y85. N. P. Lobusevich, L. A. Malysheva, T. D. Novikova, S. A. Golubtsov, and L. 0. Sporykhina. J . Gen. Chern. (U.S.S.R.), 1973. 43, 947. V. F. Mironov and T. K. Gar, J. Gem. Chem. (U.S.S.R.), 1973, 43, 797. L. G. Sakovich, A. J. Gorbunov, A. P. Belyi, and N. N. Rybakov, Russ. J . Phys. Chern., 1973, 47, 814.

253 Elements of Group N organotin(I1) species. Tetra-alkylammonium salts were found to be the most effective catalysts in the n-butyl bromide-tin The Si-F bond distance in SiF, has been deduced to be 1.555 f 0.002 8, from an electron-diffraction The same technique has also been applied to MeSnC1, and Me,SnCl. Both molecules are approximately tetrahedral, and the Sn-CI bond distances are, respectively, 2.306 f 0.003 The importance of d -orbital participation in the and 2.354 f0.008 bonding of chlorosilane has been the subject of a detailed theoretical The photoelectron spectra of SiF,X ( X = H , C1, Br, or Me) and Si,F, have been recorded, and assignments of the bands to molecular energy levels made.431Detailed analyses of the vibrational spectra of HSiF,,43' Me,GeF,-, (n = 1-3),'" and HGeC1, and DGeC1,434 have been carried out. The perfluorinated oligosilanes HSi(SiF,), and H,Si(SiF,), have been synthesized by the reaction of the corresponding methoxysilane with boron t r i f l u ~ r i d e .The ~ ~ ~reaction of bromotrifluorosilane with MAl(PH,), (M = Li or Na) yields the fluorosilylphosphine F,SiPH,. The reaction of this compound with (F,C)2EI ( E = P or As) causes cleavage of the Si-P bond and the formation of F,SiI and (F,C),EPH,. Adducts with BCl,, BBr,, and AlCl, are also formed.436 Dichlorocarbene derived by the thermolysis of PhHgCCl, inserts into the M-Br bonds of MBr, (M=Si, Ge, or Sn), producing BrC12MBr3compounds. In the case of SnBr,, halogen exchange with further SnBr, results in the formation of Br,ClCSnBr,.437 Trichlorosilane reacts readily with alkoxyphenylmagnesium bromides ArMgBr, forming the corresponding Ar,SiH Chlorosilanes R,SiCI exchange with cobalt hydride complexes such as (diphos),CoH to form R,SiH and (diph~s),CoH.'~~ The interaction of chlorosilanes with various cobalt carbonyl species has been investigated. Dicobalt octacarbonyl and MeSiC1, in THF give methinyltricobalt enneacarbonyl derivatives, whilst SiC1, in THF reacts to produce Cl3Si0CCo,(CO),. The same reactions in ether do not proceed. The reactions with NaCo(CO), in THF and ether also give similar products.""" Binary systems composed of a copper compound and an isocyanide are effective catalysts for the hydrosilylation of acrylonitrile by

4ZR

H. Matschiner, R. Voigtlander, and A. Tzschach, J. Organometallic Chem., 1974, 70, 387. Beagley, D. P. Brown, and J. M. Freeman, J. Mol. Structure, 1973, 18, 337. J . M. Howell and J. R. Van Wazer, J. Amer. Chem. S O C . , 1974, 96, 3064. S. Cradock, E. A. V. Ebsworth, and R. A. Whiteford, J.C.S. Dalton, 1973, 2401. H. Burger, S. Biedermann, and A. Ruoff, Spectrochim. Acta, 1974, 30A, 1655. J. W. Anderson, G. K. Barker, A. J. F. Clark, J . E. Drake, and R. T. Henderson, Spectrochim. Acta, 1974, 30A, 108 1 . A. Ruoff, H. Burger, S. Biedermann, and J. Cichon, Spectrochirn. Acta, 1974, 30A, 1647. F. Hofler and R. Jannach, Inorg. Nuclear Chem. Letters, 1974, 10, 711. G. Fritz, H. Schafer, R. Demuth, and J. Grobe, Z. anorg. Chem., 1974, 407, 287. M. Weidenbruch and C . Pierrard, J. Organometallic Chem., 1974, 71, C29. I. I. Lapkin, R. G. Mukhina, N. F. Kirillov, and L. 1. Sigova, J. Gen. Chem. (U.S.S.R.), 1973, 43, 773. N. J. Archer, R. N. Haszeldine, and R. V. Parish, J. Organometallic Chem., 1974,81,335. B. K. Nicholson, B. H. Robinson, and J . Simpson, J . Organometallic Chem., 1974, 66,C3.

"' B. 43"

"'

432 433 434

43s 436 437 438

43y 440

254

Inorganic Chemistry of the Main-group Elements

trichlorosilane and methyldichlorosilane.""' The thermal decomposition of p -trifluoroethylsilanes CF,CH,SiF, Me3_, (x = 0-3) involves the elimination of CF,CH,.""' The predominant products from the reaction of germanium tetrachloride with elemental boron at elevated temperatures are, at 550-600 "C, boron trichloride and elemental germanium; at 600-800 "C, boron trichloride and germanium dichloride; and at 900-1 100 "C, boron trichloride and germanium m o n ~ c h l o r i d e . "Germanium ~~ tetrachloride is solvolysed in a stepwise manner by Ether complexes of trihalogenogermanes condense readily with adamantyl halides to form adamantylgermane derivatives in good yield.""' Mono-organotin trifluorides are conveniently obtained by treatment of the corresponding tris(carboxy1ates) with concentrated hydrofluoric acid at room temperature. Like the mono- and di-fluorides, they are considered to be polymeric uia fluoride bridges .446 Methyltin chlorides undergo solvolysis in highly acidic media, producing solvated [Me,Sn]+, [ M ~ , S ~ I ] ~[MeSnCl,]', *, and [MeSnCI]" cations in solution.",' Analysis of the e.p.r. spectra of the 1 : l complexes formed between aliphatic nitroxides and Group IV Lewis acids has revealed the following order of acceptor strength: SnCl, > SnBr, > SiF, b Bu2SnCr(C0)5= SiCl, b GeC14.448 The stability of the SiF:- ion in aqueous solutions of fluorosilicic acid has been studied by 19Fn.m.r. spectroscopy, which shows that it is not the only fluorosilicate-containing component present. The stability and concentration of the SiF:- ion decrease with increase in temperature and with increase in the hydrogen ion c~ncentration.""~ Both CaGeF6,2Hz0and SrGeF,,2H20 are cubic, with cell constants a = 14.9 and 16.9 A, respecti~ely."~' Germanium may be extracted from hydrofluoric acid solutions as complex ammonium salts of the GeFi- ion by the addition of amine~."'~ The tin-119 Mossbauer spectra of alkali-metal salts of the SnFi- ion as well as those of water and HF solvates have been recorded. The measured isomer F n.m.r. shifts define the lowest point of the "'Sn chemical-shift sca1e.45z,453 spectroscopy has been used to demonstrate the existence of fluorinebridged polymeric fluorostannate ions in liquid sulphur dioxide solution. In

"'

P. Svoboda a n d J. Hetflejs, Coll. Czech. Chem. Comm., 1073, 38, 3834. T. N. Bell, R. Berkley, A. E. Platt, and A. G . Sherwood, Canad. J. Chem., 1974, 52, 3 158. 143 G. M. Gacilov a n d V. 1. Evdokimov, Russ. J . Inorg. Chem., 1973. 18, 915. 144 I. N. Nazarova, I . I . Seifullina, E. M. Belousova, and D. I. Chubar, J. Gen. Chem. (U.S.S.R.), 1973, 43, 1505. 445 V. F. Mironov and T. K. G a r , J. Gen. Chem. (U.S.S.R.), 1974, 44, 447. "' V. I. Shiryaev, L. V. Makhalkina, T. T. Kuz'mina, V. D. Krylov, V. G . Osipov. and V. F. Mironov. J. Gen. C'hem. (U.S.S.R.).1973. 43, 2223. 4 4 7 T. Birchall, P. K. H. Chan, a n d A. R. Pcreira. J.C.S. Dalton, 1974, 2157. "' A. H. Cohen and B. M. Hoffman, Inorg. Chem., 1974, 13, 1484. 4Jy P. M. Borodin, N. K. Z a o , and N. S. Petrov, J. Struct. Chem., 1073, 14, 564. B. Hajek and F. Benda, Z . Chern., 1974, 14, 365. 45' A. I . Vasyutinskii, N . A . Kisel', N . M. Varlamova, and Z h . V. Kunshenko, Russ. J. Inorg. Chem., 1973, 18, 1312. 4 s 2 F. W. D. Woodhams, R. A. Howie, and 0. Knop, Cunud. J. Chem., 1974. 52, 1904. 453 V. K. Sokolova, I. I. Tychinskaya, V. A. Varnek, and N. F. Yudanov, J. Struct. Chem., 1973, 14, 512.

Elements of Group IV

255

the SnF,-(Pr,NH,),SnF, system, both Sn2F:; and [(SnF,),]"-, which has a structure consisting of cis -fluorine-bridged SnF, octahedra, occur.454The energies for the reaction MCli-(g) + M4'(g) + 6Cl-(g) have been calculated to be 2364* 20 kcal mol-' (M = Ge), 2144 f 20 kcal mol-' (M = Sn), and 2151k20 kcal rno1-I (M=Pb), and probably reflect the trend in bond strength along the The effect of pressure on the far4.r. spectra of some hexachlorometallate salts has been examined. No simple pattern of behaviour is discernible, although the v, [6 (ClMCl)] mode is generally much more pressure-sensitive than the corresponding v 3 [v (M-C1)].456 The hexafluoroplumbate salts MPbF6,6H,O (M=Co, Ni, Zn, or Cd) have been prepared and are hexagonal and isotypic with the analogous Ti, Zr, Hf, and Si salts. CuPbF,,4H20 was also obtained and was thought to have lower ~ymmetry.~" Trichlorosilane reacts with 1,lO-phenanthroline to form a pink 1: 1 adduct. The pink coloration is due to the presence of small amounts of imp~rity."~' The germanium tetrachloride complex with the hydrazide of nicotinic acid undergoes solvolysis with water and a l ~ ~ h oOfl ~the. ~ large ~ ~ number of papers relating to complexes of tin tetrahalides, only those by Ohkaku and N a k a r n ~ t o ~are ~ "worth ~ ~ ~more than a passing mention. These authors have carried out a detailed assignment of the far4.r. spectra of octahedral adducts of tin tetrahalides with both trans and cis geometries on the basis of observed '16Sn-""Sn isotope shifts. Whereas complexes with chelating ligands such as 2,2'-bipyridyl, 1,l0-phenanthroline, 1,2-dimethyIthioethane, and 1,2-bis(diphenylphosphino)ethaneare necessarily cis, the complexes formed with the unidentate ligands pyridine, y-picoline, t-butylpyridine, THF, PPh,, and AsPh, all adopt the trans stereochemistry. Other systems which have been studied include CCl,, SiCl,, and GeCl, with sulphuryl chloride ;462 germanium and tin tetrahalides with diphenylcartin tetrabazone, diphenylthiocarbazone, and diphenylthi~carbazide,"~~ chloride with POC1, and SeOCl,,""" Schiff bases,",' copper and nickel chelates

454

455

45h 457

458

45y

460 461

462

461 464

4hS

P. A. W. Dean, Canad. J . Chem., 1973, 51, 4024. W. A. Welsh, T. B. Brill, P. T. Thompson, R. H. Wood, and R. C. Gearhart, Inorg. Chern., 1974, 13, 1797. D. M. Adams and S. J. Payne, J.C.S. Dalton, 1974, 407. R. L. Davidovitch, T. F. Levchishina, and T. A. Kaidalova, Russ. J. Inorg. Chem., 1973, 18, 325. K. Hensen and U . Trobs, Chem. Ber., 1974, 107, 3176. I. N. Nazarova, E. M. Belousova, P. 1. Seifullina, and L. M . Kramarenko, Russ. J. Inorg. Chem., 1973, 18, 1280. N . Ohkaku and K. Nakamoto, Inorg. Chem., 1973, 12, 2440. N. Ohkaku and K. Nakamoto, Inorg. Chem., 1973, 12, 2446. T. N . Naumova, T. S. Vvedenskaya, L. S. Zhevnina, and B. D . Stepin, Russ. J . Phys. Chem., 1973, 47, 1257. S. A. A. Zaidi and K. S. Siddiqi, Indian J. Chern., 1973, 11, 1179. L. A. Nisel'son, K. V. Tret'yakova, E. N . Torbina, V. G. Lebedev, and G . V. Ellert, Russ.J. Inorg. Chem., 1973, 18, 1500. V . A. Kogan, A . S. Egorov, and 0. A . Osipov, Russ. J. Inorg. Chem., 1973, 18, 1106.

256

Inorganic Chemistry of the Main- group Elements

of a z o - c o m p ~ u n d s , "N-benzylidene~~ and N-s-butylidene-alkyl- and -aryla m i n e ~ ,n-C5H11C02H,4"s ~~~ S -alkyl diethylphosphinothioites,""' alkyl hydrogen phenylph~sphonites,~'" and substituted a n i l i n e ~ ;N-acyl-substituted ~~' amides4" and 3-substituted pyridine~'~' with tin tetrahalides ; tin tetrabromide with d i ~ x a ntin ; ~tetrachloride ~~ and tetrabromide with /3 -diketones, 8-hydroxiquinoline, salicylaldehyde, and acetoa~etanilide,"~~ and with bis(2mercaptoethyl) ether.476Tin tetrachloride-oxime complexes react with alcohol hydrogen sulphate esters to give the lactam-tin tetrachloride complex and the oxime hydrogen ~ u l p h a t e . ~ ~ ~

Figure 13 The structure of Ph,SnCl,,bipy (Reproduced from J . C . S . Dalton, 1974, 1723) 466

4h7

46x

46e

47')

47'

472

J73 474 475 476

477

V. A. Kogan, V . V. Kuznetsov, 0. A . Osipov, V. P. Grigor'ev, A . S. Burlov, S. S . Kucherenko, V. P. Sokolov, and A. V. Naumov, J . Gen. C'hem. ( U . S . S . R . ) ,1974, 44, 683. V. A. Kogan, A. S. Egorov, 0. A. Osipov. and V. P . Sokolov. J . Gen. Chem. ( U . S . S . R . ) . 1973, 43, 2696. V. N. Mbrchenko and A. 1. Pletnev, J . Gen. Chem. ( U . S . S . R . ) ,1973, 43, 1420. A. N.Pudovik. 1. Ya. Kuramshin, A. A. Muratova, R. A. Manapov, E. G. Yarkova, and G. M. Mirsaitova, J . Gen. Chem. ( U . S . S . R . ) ,1973, 43, 1186. A . A. Muratova, E. G. Yarkova, V. P. Plekhov, N. R . Safiullina, A. A . Musina, and A. N . Pudovik, J . Gen. Chem. ( U . S . S . R . ) , 1973, 43, 1677. S. A. A. Zaidi a n d K. S. Siddiqi, Indian J . Chem., 1973, 12, 429. T. N . Sumarokova, R. A. Slavinskaya, T. A. Ternbcr. M. K. Moldahacv, M. F. Vereshchek. and A. K. Zhethacv, Russ. J . Inorg. Chem., 1973, 18, 814. P. P. Singh, S. A. Khan, and A. K. Srivastava, Indian J. Chem.. 1974, 12, 192. R. C. Maheshwari, S . K . Suri, a n d V. Ramakrishna, Indian J . Chem., 1973,11,1196. S . Gopinathan, C. Copinathan, and J. Gupta, Indian J. Chern., 1973. 12, 626. R. Engler, Z . anorg. Chem., 1974, 407, 35. M. Masaki, K. Fukui, M. Uchida. K. Yamamoto, and I . IJchida, Bull. Chem. SOC. Japan, 1973, 46, 3179.

Elements of Group IV

257

Several papers have appeared concerning the structures of complexes of organo-tin and -lead halides with donor molecules. The crystal structures of two complexes of diorganotin dihalides have been determined. Diphenyltin dichloride bipyridyl possesses cis chlorine atoms [r(Sn-C1) = 2.509 A] and trans phenyl groups [r(Sn-C) = 2.152 A] (Figure 13).478The complex between dimethyltin dichloride and N"-ethylenebis(salicy1ideneiminato)nickel(r1) also contains octahedrally co-ordinated tin and is shown m Figure 14. Again the organic groups are mutually trans [r(Sn-C) = 2.12 A] and This the chlorine atoms mutually cis [r(Sn-C1) = 2.433, 2.523 A].479

Figure 14 The structure of the dimethyltin dichlaride complex of N"ethylenebis (salicylideneiminato)nickel(~~). (Reproduced by permission from J. Organometallic Chem., 1974, 76, CS6) stereochemistry has also been inferred for a number of homologous complexes R,SnX,Ni(salen), from spectroscopic data. Octahedrally co-ordinated tin is also present in the RSnX,Ni(salen) c o r n p l e x e ~ . ~Dimethyltin "~ dichloride bis(dimethy1 sulphoxide) has been subjected to a single-crystal and solution Raman study. The chlorine atoms and sulphoxide groups are both mutually cis whereas the methyl groups occupy trans positions.""' Far4.r. 47x

47')

4R"

4x'

P. G. Harrison, T. J . King, and J. A . Richards, J.C.S. Dalton, 1974, 1723. M. Calligaris, L, Randaccio, R. Barbieri, and L. Pellerito, J. Organornetallic Chern., 1974, 76, CS6. L. Pellerito, R . Cefalu, A. Gianguzza, and R. Barbieri, J. Organornetallic Chern., 1974, 70, 303. V. B. Ramos and R. S. Tobias, Spectrochirn. Acta, 1974, 30A, 181.

258

Inorganic Chemistry of the Main-group Elements data for bis(amide) complexes of diaryltin dihalides show that the cis halogen/trans -organic group again occurs, and that the amido-group coordinates to tin via the oxygen rather than the nitrogen atom.482Both the Me3SnC1:- anion and the complex Me3SnC1,bis(acetylacetone)ethylenediimine are considered to possess six-co-ordinated tin atoms with T-shaped SnC, units."? Equilibrium constants have been derived for Me,SnX,B complexes (X.= halogen; B = donor ligand)484and alkyltin fluoride cationic species.485The structure of the complex formed by trimethyl-lead chloride and methylaluminium dichloride has been investigated by spectroscopic techniques. A structure similar to that of solid Me,PbCl is proposed, in which [MeAlCl,] units bridge [Me,Pb] r n ~ i e t i e s . " ~ Pseudohalide Derivatives of Silicon, Germanium, Tin, and Lead.-The novel pseudohalide-silane derivatives HSi(NCO), and HSiCNCS), have been synthesized from the silver pseudohalide and trihalogenosilane. Mixed compounds such as HSiX,(NCO) (X=Cl, Br, or I), HSiX(NCO),, H2SiC1(NCO), HSiY,(NCS) (Y=C1 o r Br), and HSiCl(NCS), may be obtained by halogen-pseudohalide exchange between Si(NCE)4 ( E = 0 o r S) and the appropriate trihalogenosilane."' M O calculations have been carried out on H3SiNC04" and H,SiCN, H,SiNC, and (H,SiCN),.48y The calculated minimum geometry for H,SiNCO is in agreement with spectroscopic The i.r. spectrum of trimethylcyanogermane indicates the presence of ca. 5% of the isocyanide. From microwave data, the following structural parameters were deduced: r(Ge-C) = 1.930 f0.006 A; LCGeCN = 106.2 f O.l"."'" The crystal structure of triphenyltin isothiocyanate has been determined. - - - SnMolecules are arranged in infinite zig-zag =S * * Sn-N=C=S chains, with r(Sn-C) = 2.0(3) A; r(Sn-N) = 2.22(5) A; r(Sn-S) = 2.92(1) A (Figure lS).'" Co-ordination numbers in excess of four for tin have also been deduced f o r a number of organotin pseudohalide derivatives from Mossbauer data.492Tetraphenylarsonium and tetramethylammonium salts of the complex pseudohalide-lead anions [Ph3Pb(N3)J, [Ph,Sn(N,)(NCS)]- , [P h2SnP b(N,),l2-, and [P h,Pb( N3)(NCS)J2 have been synthesized . Spectroscopic data suggest planar Ph,Pb and linear Ph2Pb units except for

'" T. N. Srivastava, Indian J . Cherri., 1974. 12, 98. '" R. Barbieri and G. c'. Stocco, Gazzetta, 1974, 104,

139. V. S. Petrosyan, N. S. Yashina, V. I. Bakhmutov, A. B. Permin. and 0. A . Rcutov. J . Organornetallic Chern., 1974, 72, 7 I . 4x5 F. Magno, G. Bontempelli, and G. A . Mazzocchin, J . Organornetallic Chem., 1974, 67, 33. '" M. Boleslawski, S. Pasynkiewicz, and M. Harasimowicz, J. OrgnriometalIic Chem., 1974. 7 8 , 61. *" F. Hiiflcr. G. Jagerhuber, and W. Veigl, Monatsh., 1974, 105, 539. 48H B. M. Rode, W. Kosmus, and C. Nachbaur, Monarsh., 1974, 105, 191. 4x') W. Kosmus and E. Nachbaur, J. Mol. Structure, 1974. 23, 113. 4 y o J. R . Durig, Y. S. Li, and J. B. Turner, Inorg. Chem., 1974. 13, 1495. ")I A . M. Domingos and G. M. Sheldrick, J . Organometallic Chem.. 1974, 67, 257. ~'')' L. Korecz, H. Kohler, L. Neef, and K. Burger. J. Orgunornetallic Chem.. 1974. 69, 105. 4x4

Elements of Group IV

259

Figure 15 Projection of the asymmetric unit of triphenyltin isothiocyanate (Reproduced by permission from J. Organometallic Chem., 1974,67,257) the latter species, for which a bent Ph,Pb unit is The distribution of Me,Pb between the anion-exchange resin Dowex 1 x 8 and aqueous solutions of NaSCN and KSCN has been investigated. In the aqueous phase, up to 3mol 1-' thiocyanate concentration, only the formation of neutral Me,PbNCS was detected. Some evidence for the formation in the resin phase of anionic [Me,Pb(NCS),]- was obtained."'"

Sulphur and Selenium Derivatives of Silicon, Germanium, Tin, and Lead.The heats of formation of SnS and a - S n S , have been deduced to be -26.2 f0.3 and -28.4 f0.5 kcal (g formula)-'.49sThermal decomposition of 493

494

495

N. Bertazzi, G. Alonzo, G. C. Stocco, and L. Pellerito, J . Organometallic Chem., 1974, 80, 225. N. Bertazzi, Z. anorg. Chem., 1974, 410, 316. M. P. Morozova, T. A. Stolyarova, and I. Ya. Nekrasov, Russ. J. Phys. Chem., 1973, 47, 1235.

Inorganic Chemistry of the Main-group Elements 260 SnS, produces tin sesquisulphide, Sn,S,.'"" Tin(iv) selenide SnSe, decomposes to produce only tin(r1) selenide SnSe, and tin(iv) selenosulphide gives tin(r1) selenosulphide SnSSe, which is isomorphous with SnS and SnSe.497 The structures of several thio-germanates and -stannates have been determined. Sodium orthothiostannate, Na,SnS,, 1 4 H 2 0 , prepared from aqueous solution, contains tetrahedral isolated SnS: ions [r(Sn-S) = 2.37s2.384 A], and suggests that octahedral six-co-ordination is unstable in

Figure 16 Projections of the structures of ( a )Na,X,S, ( X = Ge or Sn) and ( b ) Ba3X2S, (Reproduced by permission from Reu. Chim. rninirale, 1974, 11, 13) -196

S. Ichzba, M Katada. and H. Negita, Chrm I rtlers, 1974, 970 Ichiba, M Katada, and H. Negita, Chem Letten. 1974. 1961

"' 3'

Elements of Group IV

261

I(

Figure 17 Projection of the structure of La,Ge,S,, (Reproduced by permission from Actu Cryst., 1974, B30, 759) thiostannates from aqueous The crystal structure of La,SnS, contains nine-co-ordinate lanthanum atoms and six-co-ordinate tin atoms [r(Sn-S) = 2.529, 2.591 A].499Structural studies show that Na,Ge& and Na,Sn,S7 are isotypic. The crystal structures of these compounds and of Ba,Sn,S, are built up from M,S67- thioanions and Na' or Ba2+cations. The M,S;- anion results from the condensation of two MS, tetrahedra with one common apex. Projections of the two structures are shown in Figure 16.500 The structure of La,Ge,S,, is built up of GeS, tetrahedra and sulphur prisms around the lanthanum atoms. Part of the structure is shown ingrojection in Figure 17. The Ge-S bond distances fall in the range 2.19-2.23 The CSM and MSM bond angles in the series of Group IV sulphides PhSMMe,, rn- and p-Cs&SMMe3, and Me3MSMMe3(M = C, Si, Ge, or Sn) have been estimated from dipole-moment data. The bond angles increase significantly from Ph,S to the compounds of the series PhMMe, and Me3MSMMe,.502 Bonding characteristics of these compounds have been discussed in the light of both mass spectral and photoelectron data.5037504 The photoelectron spectra of methyl silyl sulphide and disilyl sulphide have also 4YX

JYY 500

SO 1

so2 snR

fit14

W. Schiwy, S. Pohl, and B. Krebs, Z. anorg. Chem., 1973, 402, 77. S. Jaulmes, Acta Cryst., 1974, B30, 2283.

J. C. Jumas, J. Olivier-Fourcade, F. Vermont-Gaud-Daniel, M. Ribes, E. Philippot, and M. Maurin. Rev. Chirn. minirale, 1974. 11, 13. A. Mazurier and J. Etienne, Acta Cryst., 1974, B30, 759. S. Sorriso, A . Foffani, A . Ricci, and R. Danieli, J . Orgunometullic Chem., 1974, 67, 369. G. Distefano, A. Ricci, D. Pietropaolo, and S. Pignataro, J. Organometallic Chem., 1974, 78, 93. G. Distefano, A. Ricci, R. Danieli, A. Foffani, G. Innorta, and S. Torroni, J . Organometallic Chern., 1974, 65, 205.

262

Inorganic Chemistry of the Main - group Elements

been examined and interpreted.’” From i.r. and Raman spectral data for Me,MSC(=S)Me ( M = S i , G e , Sn, or Pb), it has been concluded that the bonding is similar to that in organic dithioacetates and that there is negligibly small interaction between the thiocarbonyl group and the Group IV rneta1.’O6 The crystal structure of Ph,GeSC&Bu‘ has been determined. The compound is isostructural with its tin analogue and contains tetrahedral germanium, with r(Ge-C) = 1.938 8, and r(Ge-S) = 2.229 A (Figure l8).’()’ The Mossbauer spectra of a large number of triorganotin arylmercaptides have been observed. The quadrupole splittings for the two series R,SnSC,H,X-p ( X = H , Me, But, C1, Br, NHZ, NOz, o r OMe; R = M e or Ph)

23 c21 24

c 20

Figure 18 “ h e structure of Ph,GeSC,H,Bu‘ (Reproduced by permission from J. Organornetallic Chern., 1974, 66, 43) ’(’’

506

5(17

P. Mollere. H . Bock, G. Recker, and G. Fritz. J . Orgunomrtullic Chem.. 1973, 61, 127. S. Kato. A. Hori, H. Shiotani, M. Mizuta, N. Hayashi, and T. Takakuwa, J . Orgunornetullic, Chrm., 1974, 82, 223. M. E. Cradwick. R. D. Taylor, and .I.1.. Wardell, .1. Organometallic Chern., 1974, 66, 3 3 .

Elements of Group IV

263

correlate with the Taft parameters for the substituents X.’08 Hexaorganodistanthianes and -diplumbthianes react with carbon tetrachloride in the presence of freshly precipitated copper with the formation of the corresponding triorganometal chloride. Under the same conditions, hexachloroethane reacts to give the triorganotin chloride, tetrachloroethylene, and copper sulphide, and t-butyl peroxide reacts to give triorganotin t-butoxide. Dichlorotriphenylphosphorane reacts with Bu,SnSSnBu, to give Bu,SnCl and Ph,PS.509The reactions of the Pb-S bond in triphenyl-lead arylmercaptides have been studied in detail. Unlike the corresponding reactions of the analogous germanium and tin compounds, reactions with halogens, sulphur(1r) halides, carbon halides, and mercury(I1) halides do not lead exclusively to cleavage of the Pb-S bond. Instead, numerous types of reaction, including phenyl-lead bond fission, decomposition of organolead(1v) compounds to inorganic lead(1i) compounds, and photochemical reactions with chlorinated hydrocarbon solvents can occur, making the reactions usually complex.5i0 Stapfer and Herber have synthesized several organotin derivatives of mercapto-esters and investigated their structures by i.r. and Mossbauer spectroscopies. The large value of the quadrupole splitting found for tin(1v) SS’S”S”’-tetrakis(is0-octylthioglycolate) suggests a structure involving six-co-ordinate tin with two unidentate and two bidentate thioglycolate groups, with the two unidentate groups probably in trans positions.s’ ’ Organotin derivatives of mercapto-esters of the general formula Ri-,Sn[S(CH,), ,,,C0,R2], adopt a variety of structures, depending o n the value of n and also the mode of preparation of the Diphenyltin bis(NN-diethyldithiocarbamate)possesses an octahedrally coordinated tin atom, with both dithiocarbamate residues functioning as bidentate ligands (Figure 19). The two dithiocarbamato-groups are not equivalent; one is bonded almost symmetrically [r(Sn-S) = 2.6 13(5), 2.637(5) A], whilst the other is attached in an unsymmetrical way [r(SnS) = 2.548(5), 2.790 A]. The two phenyl groups occupy cis positions [LCSnC = 101.4(6)”; r(Sn-C) = 2.17, 2.18 A].’’, Mossbauer spectroscopy has been used to investigate the solid-state structure of cis -dicyanoethylene-l,2-dithiolatotin (mnt) derivatives. The diorganotin derivatives R,Sn(mnt) are polymeric, exhibiting a room-temperature spectrum. The mnt group in the [R,Sn(mnt)]- anions appears to be unidentate. Five-coordinate tin occurs in the [R,SnX(mnt)]- anions, whilst six-co-ordination with cis organic groups is present in the [R2Sn(mnt)I2-anions. The isomer shifts of the [Sn(mnt)J- ion show a marked cation dependence, and this is interpreted in terms of distortion of the co-ordination ~ p h e r e . ” ~

510

”’

‘I2

‘I3

P. L. Clarke, R. A. Howie, and J. L. Wardell, J. Inorg. Nuclear Chem., 1974, 36, 2449. G. A. Razuvaev, 0. S. D’yachkovskaya, I. K. Grigor’eva, and N. E. Tsyganash. J. Gen. Chern. (U.S.S.R.), 1974, 44, 550. P. L. Clarke and J. L. Wardell, J.C.S. Dalton, 1974. 190. C. H. Stapfer and R. H. Herber, fnorg. Nuclear Chern. Letters, 1974, 10, 161. C. H. Stapfer and R. H. Herber, J. Organometallic Chem., 1974, 66, 425. P. F. Lindley and P. Carr, J. Cryst. Mol. Structure, 1974, 4, 173. C. W. Allen and D. Brown, fnorg. Chem., 1974, 13, 2020.

264

Inorganic Chemistry of the Main -group Elements

Figure 19 The structure of bis (NN-diethy1dithiocarbamato)diphenylstannane (Reproduced by permission from J. Cryst. Mol. Structure, 1974, 4, 173) Drake et al. have characterized several silyl and germyl selenides. H,SiSeMe, H,Si(SeMe),, and MeH,SiSe can be obtained by the reaction of lithium tetramethylselenoaluminate with the appropriate bromosilane. The germyl selenides H,GeSeMe, MeH,GeSeMe, and Me,HGeSeMe are prepared by exchange reactions between Me,SiSeMe and the chlorogermane. The vibrational spectra for H,SiSeMe have been assigned and a normalco-ordinate analysis has been carried

Nitrogen and Phosphorus Derivatives of Silicon, Germanium, and Tin.The dissociation of P-Ge,N, into germanium metal and nitrogen gas has been studied mass spectroscopically. From the results, the heat and entropy of formation of p-Ge,N, have been deduced to be -109* 10 kcal mo1-’ (AH&,)and -79* 10 e.u. (AS&).s16Several mixed germanium nitride systems have been investigated by powder X-ray diffraction. The Li,N-Ge,N, system is composed of four phases: Li,GeN,, which is cubic; Li,GeN,, which is isostructural with the silicon analogue; Li,GeN,; and LiGezN,.”” Studies of the Mn-Ge-N system reveal the existence of MnGeN, as a stable compound and a perovskite phase formulated as Mn,+,Ge,-,N, ( 0 . 8 4 s y s 1). The ideal cubic cell shows a tetragonal distortion according to the 515

51h 417

G. K . Barker, J . E. Drake, and R . T. Hemmings, J.C.S. Dalton, 1974, 450. A . M. Vorob’ev. G. V. Evseeva, and L. V. Zenkevich, Russ. J . Phys. Chem., 1973, 47, 169 1. J. David, J . P. Charlot, and J. Lang, Rev. Chim. minerale, 1974, 11, 405.

Elements of Group IV

265

composition.s18The solid solution Gal-, Ge, Cr,N has also been studied."' Adducts of tetrafluorosilane with secondary amines may be dehydrofluorinated by a number of reagents at elevated temperatures, including LiAlH, (200 "C), NaBH, (200 "C), B,H, (190-200 "C), and electropositive metals (350 "C) to afford the substituted amino-fluoro-silanes SiF4-,(NR,), (R = Me, n = 1 or 2; R = Et, n = 1). SiF, also slowly reacts with alkali metals in liquid NHMe, at 25°C to give SiF,(NMe,),. N-Substituted hexafluorodisilazanes (SiF,),NR ( R = H , Me, Et, Ph, or NMe,) may be obtained by heating SiF, and primary amines with LiAlK. The chief or only products from the SiF,-NH,R-B,H, reactions are the borazoles B3H3N3R,. The adduct SiF,,2NH2Me is not dehydrofluorinated when heated with NEt,, NH,Ph, zinc, or Fe(CO)5, but above 300 "C some disproportionattion of the amine occurs.52" The basicity of l-diethylamino-3,5,7-trimethyl-l,3,5,7-tetrasila-adamantane has been estimated by measuring the pK, in 40%-60% waterTHF solution. The value determined (8.32 0.02) indicates that the compound is significantly less basic than analogous carbon a m i n e ~ . 'Octa~~ methylcyclotetrasilazane (omt) reacts with halides of the early transition series to give adducts of the type (MC13),,omt,2L ( M = T i or V, L = T H F ; M = Cr, L = NMe,) and (MCl,),,omt (M = Ti). The co-ordination of the silazane to the transition metal appears to occur through only two of the four available nitrogen donor atoms, to give hexaco-ordinated complexes (Figure 20a). Hexamethylcyclotrisilazane (hmt) and titanium(1v) chloride give (TiCl,),,hmt as a neutral six-co-ordinate species for which the structure shown in Figure 20b has been (Me,Si),N reacts with TiCl, in benzene to give the heterocycle (C1,TiNSiMe3),."3 The reaction of anhydrous thorium tetrachloride with LiN(SiMe,), in THF yields ThCl[N(SiMe3)2]3.524 The corresponding copper derivative (Me,Si),NCu couples with aryl iodides to give the N-arylated disilazanes ArN(SiMe,),, which may be methanolized to give the primary amines ArNH2.525The fixation of trimethylsilylnitrene has been accomplished as p3-trimethylsilylimidocomplexes of ruthenium, cobalt, and rhodium. The reaction of Me,SiN, with Ru3(CO),, gives p3-trimethylsilylimido (decacarbonyl triruthenium), whilst the reaction of Me3SiN3with cyclopentadienylcobalt or tris(cyc1opentadienylrhodium) dicarbonyl affords ~S-trimethylsilylimido-~3-carbonyl-tris(cyclopentadienyl-cobalt and A similar iron complex has also been synthesized. The reaction of di-iron enneacarbonyl with N-trimethylsilylbenzophenonimine leads to the formation of red, diamagnetic

*

'In 5'y 52"

521 522

523 524 525

526

J. Guyader, M. Maunaye, and Y . Laurent, Rev. Chim. minirale, 1974, 11, 449. M. Nardin, G . Lorthioir, and R. Fruchart, Bull. SOC. chim. France, 1973, 2959. M. Allan, B. J . Aylett, I . A. Ellis, and C. J . Porritt, J.C.S. Dalton, 1974, 2675.

G. D. Homer and L. H. Sommer, J. Organometallic Chem., 1974, 67, C10. J. Hughes and G. R. Willey, J. Amer. Chem. SOC., 1973, 95, 8758. M. Pierce-Butler and G . R. Willey, J. Organometallic Chem., 1973, 54, C19. D. C. Bradley, J. S. Ghotra, and F. A. Hart, Inorg. Nuclear Chem. Letters, 1974, 10, 209. F. D. King and D. R . M. Walton, J.C.S. Chem. Comm., 1974, 256. E. W. Abel, T. Blackmore, and R. J. Whitley, Inorg. Nuclear Chem. Letters, 1974, 10, 941.

(b)

Figure 20 ( a ) Schematic representation of (TiCl&,ornt and of (MCl&,omt,2L (M = Ti, L = THF; M = V, L = THF; M = Cr, L = NMe2); and ( b ) schematic representation of (TiCl&,hmt. (Dotted circle) C1, (0)NH (Reproduced by permission from J. Amer. Chem. Soc., 1973, 95, 8758)

(4

I

rn 3 R

a

09

Elements of Group IV

267

Fe,(CO),[CI,H,,NSiMe3]. The "Fe Mossbauer spectrum of the compound shows inequivalent iron atoms, which arise from ortho -metallation of one of the phenyl rings, and the proposed structure is shown in Figure 21."' The reaction of iodosilane with bis(trifluoromethy1)aminomercury yields fluorosilane, mercuric iodide, CF,N=CF,, and the previously uncharacterized NN-bis(trifluoromethy1)silylamine (CF,),NSiH,. The compound has low stability and decomposes at room temperature into SiH,P and

0"

'Si'

'

0

Figure 21 The proposed structure of Fe,(CO),[C,,H,,NSiMe,] (Reproduced by permission from J. Organometallic Chem., 1973, 61, 375)

CF3N=CF,."8 Aziridines and azetidines react with hexamethylcyclotrisilazane to give a number of products (CH,), or 3N+Me,Si-NH]x-MezSiN(CH,), or (x = 0-5), containing three- and four-membered heterocycles as the terminal functional groups.sz9Trimethyl-silyl-, -germyl-, and -stannyl-dimethylamines Me,MNMe, (M = Si, Ge, or Sn) insert into the N=C bond of benzoyl-t-butylcarbodi-imideas shown in reaction (70).The

PhCON=C=NCMe,

+ Me,MNMe,

-

PhCO-N-C

I

Me,M

yNCMe3 (70) \

NMe,

corresponding trimethylsilyl- and trimethylgermyl-substituted carbodiimides Me3M-N=C=N-CMe3 ( M = S i or Ge) are obtained by the pyrolysis of the silyl and germyl a d d u ~ t s . ' ~ Aminosulphinyl " chlorides R,NS(O)CI are best prepared by the reaction of thionyl chloride on trimethylsilylamino-compounds.s31 Product analysis and e.s.r. studies of the thermal and photochemical decomposition of Ph,SiN=NPh in CCI, indicate that the decomposition involves the homolytic fission of Si-N and N-C '17

'*' 52Y

530 531

G . Schmid, J . Pebler, and L. Weber, J. Organometallic Chem., 1973, 61, 375. V. G. Noskov, A . A . Kirpichnikova, M. A. Sokal'skii, and M. A. Englin, J. Gen. Chem. (U.S.S.R.), 1973, 43, 2079. G. A . Sytov, I>. E. Ledina, V. V. Sulima, A . M. Krapivin, V. N . Perchenko, and N. S. Nametkin, Doklady Chem., 1973, 212, 718. I. Matsuda, K . Itoh, and Y . Ishii, J. Organometallic Chem., 1974, 69, 3 5 3 . D. A. Armitage and A. W. Sinden, J. Inorg. Nuclear Chem., 1974, 36, 993.

268

Inorganic Chemistry of the Main -group Elements

bonds of the The bis(trimethylsi1yl)sulphodi-imide Me3SiN=S=N-SiMe, undergoes Si-N bond cleavage o n reaction with chlorine, giving Me3Si-N=S=N-CI. Similar reactions with CF,COCl and SC1, afford CF,CO(S,N,) and S(NSN-SiMe,),, respectively. This latter compound reacts further with SCl,, giving S4N4.Tris(trimethylsily1arnino)sulphur (Me,SiN),S may be obtained by the reaction of Me,SiNSOF, with NaN(SiMe,),.”’ Silylated bisiminophosphoranes of the type Ph,P(=NSiMe,)(C‘H2),Ph,P(=NSiMe,) ( n = 1, 2. or 3) and the similar cyclic compound (26) have been obtained from the reaction of the appropriate

silyl azide and alkylene-biphosphines. The open-chain compounds are desilylated by ethereal HCI, and undergo condensation reactions, as does the cyclic compound with fluorophosphoranes Ph,PFr n, with the elimination of fluorosilane and the formation of partially fluorinated ionic diphosphaza-phosphonium ring systern~.’~“ Wiberg has investigated the reactions of bis-silylated di-imines in detail. The thermolysis is complex, and several modes of decomposition have been elucidated. Observed pathways include disproportionation to nitrogen and tetrakis(trimethylsily1)hydrazineand also to nitrogen and tris(trimethylsilyl)hydrazine, by dimerization to tetrakis(trimethylsilyl)tetrazene, and by cleavage to nitrogen and tris(trimethylsily1)amine and also to nitrogen and bis(trimethylsily1)amine. Decomposition to hexamethyldisilane and nitrogen is not observed.575The thermolysis is free-radical in nature, and one of the radical intermediates involved is the tris(trimethylsily1)hydrazyl radical, which can react with hydrogen-donor solvents to generate radicals R which can lead to the formation of other reaction products. Thus with toluene, in addition to the five main products, tris- and bis-(trimethylsi1yl)benzylhydrazine and bis(trimethylsi1yl)benzalhydrazone are produced.576Further deuteriation studies showed that, of the five main products, two, part of tetrakis(trimethylsi1yl)hydrazine and all of tetrakis(trimethylsilyl)tetrazene, are directly formed from two molecules of bis(trimethylsi1yl)di-imine by disproportionation and dimerization, respectively. The other products arise from radical chain reactions.537The reaction of bis(trimethylsi1yl)di-imine with a1kali metals in diethyl ether results in <‘’

H . Watanahc. Y. Cho, Y . Ide, M. Matsumoto, and Y. Nagai. J . Orgunometullic C‘hem.. 1971.

78,C-t. 511

W. Lidy, W. Sundermeyer. and W. Verbeek. Z. anorg. Chem., 1974. 406, 228. Appel and 1. Ruppert, Z. anorg. Chem., 1974, 406, 13 1 . Wiberg and W. Uhlenbrock, J. Orgarzornetalliu Chem., 1974, 70, 239. N. Wiberg and W. Uhlenbrock, J. Orgunometullic Chem.. 1974, 70, 249. ’-”N. Wiberg, W . Uhlenbrock, and W. Baumeister, J. Organometallic Chem., 1974. 70, 259.

’-”R. ’-’’N. ”(’

Elements of Group N

269

reduction to the dianion and the radical monoanion, which is thermally unstable and decomposes by two different routes to give nitrogen and bis(trimethylsilyl) amide and also to bis(trimethylsily1) amide, bis(trimethy1silyl) hydrazide, and bis(trimethylsily1) azide. The extent of the two modes of decomposition depends on the alkali-metal cation, the temperature, and the Alkali-metal derivatives of silylated hydrazines may be prepared by the metallation of the protic hydrazines by alkyl-lithium reagents and also by the reaction of alkali metals with bi~(trimethylsilyl)di-imine.~~~ Srivastava has synthesized several mixed .,beryl silyl amines from the reaction of aminosilanes with chloroboranes, as shown in reactions (71)(73). The derivatives are generally moisture-sensitive liquids."' Noth et al.

r SBCI + (Me,Si),NH

r SBNHSiMe, + Me,SiCl Ld

R

R

LO'

R = -CH2CHz-

+ (Me,Si),N

rzo>

or -CHMeCHzCHMe-

-

BN(SiMeJz + Me,SiCl

CHzO

CHzO

+ (Me,Si),N CH,O

(7 1)

-

S iMe 0CH,

"

r20~-N-B

CH,O

'I \

+ 2Me3SiC1 (73)

OCH,

have synthesized cyclic silaborazines from the reaction of phenyldichloroborane with (Me,SiNH),. From this reaction the monosilaborazine (27) or the disilaborazine (28) and/or BB'B"-triphenylborazine may be obtained,

depending on the ratio of the reactants. The reaction with (Me,SiNH), h a 1 : l molar ratio leads to the disilaborazine, NH,Cl, and a Several other silicon-nitrogen-containing ring systems have been synthesized. 1,2-Dichlorotetramethyldisilane reacts with 1,2-dime thylhydrazine

53x

539 54"

541

N. Wiberg, W. C. Joo, and E. Weinberg, J . Organometallic Chem., 1974, 73, 49. N. Wiberg, E. Weinberg, and W. C. Joo, Chem. Ber., 1974, 107, 1764. G. Srivastava, J . Organometallic Chem., 1974, 69, 179. H. Noth, W. Tinhof, and T. Taeger, Chem. Ber., 1974, 107, 3113.

Inorganic Chemistry of the Main-group Elements

270

to give (29) and with 1,2-dilithium-1,2-dimethylhydrazine to afford (30), Me, Me, SI-s1 Me?' 'NMe I I /NMe MeN\, SI-Si Me, Mel

Me, MeNHSi'NMe t i Me&i,ThMe Me2

(29)

(30)

both as crystalline solids.54zBoth Andrianov and Wannagat have obtained a number of novel ring systems with Si2SN3, Si,SN,O, S3N20, and Si,N, skeletons, using the condensation Most of the derivatives obtained by Andrianov were spiro-compounds derived from silicon tetrachloride. Wannagat has also obtained six-membered PSi,N, ring systems by condensation of RPC1, (R = Me or Ph) with (HMeNSiMe,),NMe. The reactions of these compounds with various reagents are summarized in Me

Me

Me

p\ SiMe,

Me ,Si"\S

'

I

Z/l

I

MeN,

R

R

Reagents: i, MeI;

11,

CS,; iii, CoI,;

IV.

I

P

iM e

/NMe

c' -s

II

MelSiN,: v, S,.

Scheme 1

"' F.

Hiiflcr and D. Wolfer, L. anorg. Chem., 1974, 406, 19. U. Wannagat and D. Labuhn, Z . anorg. Chem., 1973, 402, 147. "' K . A . Andrianov, A. B. Zachernyuk, and E. A . Zhdanov, Doklady Chem., 1974, 214, 29.

"'

27 1

Elements of Group IV

Scheme l.545 The cobalt and nickel complexes M(S,N,H)2 ( M = C o or Ni) may also take part in condensation reactions with chlorosilanes to give cobalt- and nickel-containing heterocyclic systems (Scheme 2)."' The N=S / /\ Me2 S, ,dN-Si, N1 NR S' -N-Si' N=S 4 ~ e ,

'

/N=S Me, */N--Si, c0-N-Si /0 S' Me, S,

"=s//

N=S ,N=S

/

/\

s\ M P H s/ %NH N , =S

/N=S \\ S, yN-SiMe2 Ni S c Z;/N-SiMe, N=S

S,

s\'

\\

,N-SiMe, c0Z;/N-siMe,

I

N=S

N=S 4'

Me,

Reagents: i, (CIMe,Si),O, Et,N; i i , (CIMe,Si),NR. (C1Me2SiNMe),, EtaN.

Et3N;

CIMe,SiSiMe2CI; Et3N; iv,

111,

Scheme 2

crystal structures of two of the derivatives (31) and (32) have been determined. The two MN,S, rings are almost planar and the siliconcontaining six-membered rings are puckered in such a way that both N=S /

S,

/N=S \\ S,codN-S

\\

.,N-Si??e,

s
(31)

NEt

"\'

>-SiMe, N - S

i

y e, /o

(32)

molecules exhibit approximate C , The reaction of methyltrichlorosilane with bis(trimethylsily1)sulphurdi-imide yields the ether-soluble s4s 546

s47

H. H. Falius, K. P. Giesen, and U. Wannagat, Z . anorg. Chem., 1973, 402, 139. U. Wannagat and M. Schingmann, Z . anorg. Chem., 1974, 406, 312. U. Thewalt and M. Schlingmann, Z . anorg. Chem., 1974, 406, 319.

272 Inorganic Chemistry of the Main- group Elements yellow compound MeSi(NSN),SiMe, €or which the structure shown in Figure 22 has been proposed .548 Low yields of geminal P,N,Cl,(NHSiMe,), have been obtained from the reaction between P,N,Cl, and hexamethyldisilazane under sealed-tube conditions.549 Yoder has investigated the structures of both trimethylsilyl and trimethylgermyl amides by i.r. and n.m.r. spectroscopy. Studies of the'"

Figure 22 The proposed structure of bis (NN'-rnethylsilanetriyl)tris (sulphur di-irnide) (Reproduced by permission from Angew. Chem. Internat. Edn., 1974, 13, 146) derivative of bis(trimethylsily1)formamide provide definite evidence for the amide structure, and the free energy for the rotational process was deduced to be 11.6 kcal mol-'. The structures of all other amides were postulated to have the imidate structure, from their n.m.r. characteristics. The free energies of activation for the intramolecular exchange of trimethylsilyl groups occur in the range 15.0-22.1 kcal mo1-1.550 The amide structure was also deduced for the trimethylgermyl amides similarly. The free energies of rotation in these cases fall in the range 15.6-19.3 kcal mol Gotze has succeeded in preparing a primary stannylamine by allowing .trit-butylphenyltin to react with KNH, in liquid ammonia at 0°C. By this reaction, Bu:SnNH, was obtained as a colourless liquid which is easily

''' H. W. Roesky and H. Wiezer, A n g e w . Chem. Internat. Edn., 1974. 13, 146. "' A. 7'.Fields and C . W. Allen, J . Inorg. Nuclear Chem., 1974, 36, 1929. "" ''l

C. H . Yoder, W. C. Copenhafer and B. Dubester, .I.Amer. Chem. SOC.,1974, 96, 42x3. C. H . Yoder, W. S. Moore, W. C. Copenhafer, and .I. Sigel, J . Orgunornetallic Chem., 1974, 82, 253.

273

Elements of Group IV

hydrolysed to the (hydr)oxide. The corresponding deuteriated compound may also be obtained by using KND, in ND,.552An excess of methyl- or benzyl-amine reacts with bis(t-butyl)bis(dimethylamino)tin to give the stannylamines Bu:Sn(NHR), (R = Me or PhCH,), which condense at 100130 “C with loss of alkylamine to yield the novel 1,3,2,4-diazadistannetidines (33) as colourless crystals. With benzonitrile this compound forms an eight-membered heterocycle (34), but with carbon disulphide or phenyl isothiocyanate the four-membered heterocycle (35) together with N=CPh-NMe

R N BuiSn’

I

‘SnBu;

’N‘

R

MeN-PhC=N

(33)

’ S

SnBu:

I

Bu3n

‘SnBu;

‘S/

(34)

(35)

isothiocyanate or carbodi-imide are produced.”’ A cyclotristannazane has been prepared which is substituted by three trimeric phosphonitrilic difluoride rings (Scheme 3).554 Methanesulphonobis(methy1imide)methyl-

+ (CF,CO),O

(Me,Sn),NP,N,F,

Me,SnNP,N,F,

+ MeCOCF,

-

Me,Sn02CCF3

+ /P3N3F5

+---

I

COCF,

Scheme 3

amidostannanes of the general composition Me,Sn[MeS(NMe),NMe&-, (n = 0, 1, 2 , or 3) may be synthesized by transamination of stannylamines Me, Sn(NMe,),-, with MeS(NMe)*NHMe. The n.m.r. spectra suggest the occurrence of an intramolecular exchange phenomenon of the type (74).’” (Me,Sn),Sn reacts with chlorosilanes Me,-, SiC1, with cleavage of the Sn-N bond to afford silastannazanes (Me,Sn),NSiMe,-, C1, (n = 0-3), which react ss2

5s3

ss4 s5s

H. J . Gotze, Angew. Chem. Internat. Edn., 1974, 13, 88. D.Hanssgen and 1. Pohl, Angew. Chern. Internat. Edn., 1974, 13, 607. H. W. Roesky and H. Wiezer, Chem. Ber., 1974, 107, 1153. D.Hanssgen and W. Roelle, J . Organornetallic Chem., 1974, 71, 231.

Inorganic Chemistry of the Main-group Elements

274 Me I

Me I

Me

Me

Me

Me

I

I

with AgNCO and AgNCS to give the corresponding pseudohalides. The reaction with S,N, gave the sulphur di-imides Me,Sn-NSN-MMe, (M = Si o r Sn).55h The crystal structure of Me,SnNMeNO, has been determined and consists of infinite chains of planar Me,Sn units bridged by -NMeN(O)Oresidues (Figure 23). Mean bond distances are Sn-0 = 2.39, Sn-C = 2.16,

Figure 23 The repeat unit in the polymeric chains of Me,SnNMeN02 (Reproduced by permission from J. Organometallic Chem., 1974, 69, 207) Sn-N = 2.33 A.s57 The structures of triorganotin succinimides, phthalimides, and hexahydrophthalimides have been investigated by Mossbauer spectroscopy. Structures involving five-co-ordinate tin and bridging nitrogen were proposed.558 The reaction of LiAl(PMe2)4 with H,SiBr, MeSiH,Br, Me,SiHBr, and Me,SiCl results in the formation of H,SiPMe2, MeSiH2PMe2,Me2SiHPMe2, and Me,SiPMe,, respectively, in good yields .559 The silylphosphines Me2HSiPH,, MeH,SiPH,, and H,SiPH, react with LiPEt, in diglyme to give the dilithiated species Me, H3-,SiPLi2, which react with methyl chloride to afford Me,H,-,SiPMe, (n = 0-2). Analogous reactions with LiPHMe give 556

H W Roesky and H Wiezer, Chem Brr 1974, 107, 3186 M Domingos and G M Sheldrrck, J Orgunometallic Chem , 1974, 69, 207 R Gassend, Y Limouzin. J C Marre. A K M A Muttalrb, and C More, J Organometalltc C h e m , 1074. 7 8 , 215 G Fritz arid H Schafer. Z . anorg Chem , 1974, 406, 167

”’ A

i 5 x

55Y

Elements of Group IV

275

Me, H3-, SiPHLi compounds. Solutions of these monometallated compounds in mono-, di-, or tri-glyme disproportionate to (Me,H,-, Si),PLi and LiPH, either on warming to room temperature or on the addition of non-polar solvents. Etherates of the petallated disilylphosphines such as (Me,%),PLi,monoglyme may be isolated by the evaporation of the solvent. In benzene solution these compounds react with methyl chloride and halogenosilanes to form disilylmethylphosphines and trisilylphosphines, respectively. The reaction of the monometallated monosilylphosphines with AlCl, in diglyme gives LiAl(HPSiMe, H3--n)4.Diglyme solutions of these compounds are stable at room temperature, and react with methyl chloride or halogenosilanes to yield the corresponding P-H deri~ative.'~'MeSiHC1(PH,) is obtained by the reaction of MeSiHCl, with MeSiH(PH,),. Cl,SiPH, may be isolated as a mixture with SiCl, and MeSiHCI(PH,) from the reaction of SiC1, with MeSiH(PH,),, but it decomposes into PH, and Si-P polymers under the reaction conditions (50°C). SiBr, reacts at room temperature with MeSiH(PH,),, whence MeSiHBr(PH,), Br,SiPH,, and Br,Si(PH,), may be obtained depending on the time of reaction. The reaction of SiBr, with MeSiH,PH, leads to the formation of Br,SiPH, in addition to MeSiH,Br. With FSiBr,, MeSiH(PH,), forms FSiBr,PH, together with MeSiHBr(PH,). In the reactions of higher fluorinated derivatives, F,SiBr, and F,SiBr, disproportionation to SiF, is preferred to Si-P bond cleavage.561Silylphosphine reacts with a number of amines and imines with Si-P bond cleavage. Both dimethylamine and diethylamine react to give the corresponding silylamine. With cyanic acid, thiocyanic acid, and hydrazoic acid, good yields of silyl isocyanate, isothiocyanate, and azide are produced. With solid cyanamide at 0 "C, disilylcarbodi-imide was obtained quantitatively. Reactions with methylamine, aziridine, thionylimide, N methylhydroxylamine, and 0,N-dimethylhydroxylamine resulted in complete decomposition of ~ilylphosphine.~~' The exchange reactions of Me,SiMMe, ( M = N , P, or As) with (CF,),M'H (M'=P or As) have been studied. The reactions involving the silylamine gave Me,SiF and a black solid. The Si-P bond in Me,SiPMe, is cleaved to give Me3SiP(CF,), and Me,SiAs(CF,),. Me,SiAsMe, reacts with (CF,),PH to give Me,SiF and Me2AsP(CF3), as isolated products, whilst reaction with (CF1),AsH affords Me,SiAs(CF,), and Me2AsH."? Derivatives of Silicon, Germanium, Tin, and Lead containing Bonds to Main-group Metals.-Triethylgermyl derivatives of the alkali metals Et,GeM ( M = L i , Na, K, Rb, or Cs) have been prepared in high yield in hexane or benzene by the reaction of bis(triethy1germyl)mercury with the appropriate alkali metal. All the compounds couple with Me,SiCl to afford "')

561

s62 507

G. Fritz, H . Schlfer, and W. Holderich, Z. anorg. Chem., 1974, 407, 266. G. Fritz and H. Schafer, Z. anorg. Chem., 1974, 407, 295. C. Glidewell, Inorg. Nuclear Chem. Letters, 1974, 10, 39. J . E. Byrne and C . R . Russ. J . Inorg. Nuclear Chem., 1974, 36, 35.

276

Inorganic Chemistry of the Main -group Elements

Et,GeSiMe,, but the reactions with benzophenone, acetophenone, and phenylacetylene are complex, and the course of the reactions depends strongly on the solvating ability of the solvent and the nature of the alkali Weibel and Oliver have carried out n.m.r. studies on solutions of LiSnMe, and KSnMe,, and have established the occurrence of an equilibrium between contact and solvent-separated ion pairs: M,SnMe3 MIISnMe,. Solvents which can solvate the alkali-metal ion, such as hexamethylphosphoramide, shift the equilibrium to the right, whilst less solvating solvents, such as THF, displace the equilibrium to the left. Variations in ’J(SnCH) for the MSnMe, species indicate that the structure of the SnC, fragment tends increasingly towards planarity with increasing solvation of the alkali metal. LiSnMe, does not attack the solvent on heating, but disproportionates to Me,Sn and LiSn(SnMe,),, a process which is enhanced by the addition of h e x a m e t h y l p h o ~ p h o r a m i d e . ~ ~ ~ Diethylzinc undergoes hydrogermanolysis with triphenylgermanium hydride in bis-2-methoxyethyl ether (BMEE) to give EtZnGePh,,BMEE and (Ph,Ge),Zn,BMEE. When the reactions were carried out in dimethylformamide (DMF) or hexamethylphosphoramide (HMPA), the analogous complexes (Ph,Ge),Zn,2DMF and (Ph,Ge),Zn,2HMPA were obtained. EtZnGePh,,BMEE undergoes reaction preferentially at the Zn-Ge bond with acetic acid and 1,2-dibromoethane. (Ph,Ge),Cd,BMEE may be similarly prepared.566In the presence of tetramethylethylenediamine, diethylcadmium reacts at 40°C with an equimolecular amount of Ph,GeH to give EtCdGePh,,TMED, but at higher temperatures (90 “C) the products from the same reaction mixture were ethane and (Ph,Ge),Cd,TMED. EtCdGePh,,TMED hydrolyses at the Cd-C and Cd-Ge bonds to give Ph,GeH, ethane, and cadmium hydroxide. (Ph,Ge),Cd,TMED reacts with acetic acid in a stepwise fashion to give Ph,GeCdO,CMe,TMED and then Cd(02CMe),,TMED, with ethyl bromide to give Ph,GeCdBr,TMED, and with cadmium halides to give Ph,GeCdX,TMED complexes (X = CI, Br, or I). The complexes R,GeCdX,TMED decompose thermally to R,GeX and metallic ~admium.’~’ The mole stable germyl-cadmium compound [(Me,SiCH,),Ge],Cd and the stannyl-cadmium compound [(Me,SiCH,),Sn],Cd are obtained by the hydrometallolysis of diethylcadmium by (Me,SiCH,),M H ( M = G e or Snj. The tin compound is readily oxidized to [(Me,SiCH,),SnO],Cd as the only product, and it reacts with lithium metal to afford the corresponding stannyl-lithium, which in turn reacts with Et,SiBr to give the triethylsilylstannane. Shaking of either the germyl- or stannyl-compound with mercury results in the formation of the germyl- o r 5h4

’‘’

’‘’

E. N. Gladyshev, N . S. Vyazankin, k. F. Fedorova, L. 0. Yuntila. and Ci. A . Ramvaev, .1. Orgunometallic Chem., 1974, 64, 307. A. T. Weibel and J. P. Oliver, J. Organometallic Chrm., 1974, 82, 28 I . V. T. Bychkov. N. S. Vyazankin, and G. A. Razuvacv, J. Gen. Chem. ( [ J . S . S . R . ) , 1973, 43, 792. G. A . Razuvaev. V. T. Bychkov, and N. S. Vyazankin, Doklady Chrm., 1973. 211, S45.

Elements of Group IV

277

stannyl-mer~urial.'~~ Mitchell has described the preparation and properties of compounds of the type RtC-Hg-MR: (M = Si, Ge, or Sn). Thermolysis and photolysis of these compounds involve free-radical intermediate^.'^^ The reaction of Bu'HgSiMe, with benzylidenemalonodinitrile gives N-trimethylsilylketenimines but other RHgSiMe, compounds do not react. NTrialkylstannylketenimines may be prepared from Bu'HgSnR, and benzylidenemalonodinitrile, from trialkyltin hydride and the adduct between bemylidenemalononitrile and BuiHg, or by transmet.allation from N-silylketenimines. This latter method is also useful for the preparation of germyland plumbyl-ketenimines.*70 Trifluorosilylpentaborane has been synthesized from LIB,& and excess SiF, in ether at -78°C. The initial product is almost exclusively the 2-isomer, which may, however, be converted into the 1-isomer catalytically by contact with resins made from p e n t a b ~ r a n e Boron . ~ ~ ~ insertion reactions with H2BC1,0R2 and Me3MB,H; anions ( M = S i or Ge) give rise to the corresponding 1-Me3MB6H9compounds, which constitute the first examples of apically substituted hexaborane( 10) derivative^.^^' In the reaction of ethylbis(triphenylsily1)aluminium with mercuric acetate, diethylmercury and bis(triphenylsily1)mercuryare isolated. Reaction with t-butyl hydroperoxide takes place at the Al-C and A1-Si bonds, with the formation of unstable organoaluminium peroxides, which rearrange into alkoxy-compounds with SiOAl linkage^.^" The complex (Ph3Si),AlEt,2LiBr,THF reacts with diphenylacetylene at the Al-Si bond. The initial reaction products were not isolated, but the major silicon-containing product obtained after hydrolysis of the reaction mixture was (1,2-diphenylvinyl) triphenyl~ilane.~'" The presence of tin-metal bonding in the species Li[Me,SnMMe,] (M = Al, Ga, In, or T1) has been established by the observation of tin-across-metal coupling and additionally, for the thallium derivatives, of thallium-acrosstin coupling in the n.m.r. The reaction of KSiH, with Si,H, or Si& leads to mixtures containing KSiH,, KSi2Hs, KSiH(SiH,),, and KSi(SiH,),."" With butyl-lithium, trisilane SiH4, Si2H6,mono- and di-butyltrisilane, and the butylreacts to give HZ, substituted polysilane SiHl.34Buo.~6. Reactions with n-tetrasilane and npentasilane proceed similarly, leading to monobutyl- and (YO-dibutyl-tetrasilanes and - p e n t a ~ i l a n e s The . ~ ~ ~Raman spectra of several higher silanes 568

-5hy

"" 571

572

573

574

575

s77

G. S. Kalinina, 0. A. Kruglaya, R. 1. Petrov, E. A. Shchupak, and N . S. Vyazankin, J. Gen. G e m . (U.S.S.R.). 1973, 43, 2215. T. N. Mitchell, J. Organometallic Chem., 1974, 71, 27. T. N. Mitchell, J. Organometallic Chem., 1974, 71, 39. A. B. Burg, Inorg. Chem., 1974, 13, 1010. D. F . Gaines, S. Hildebrandt, and J. Ulrnan, Inorg. Chem., 1974, 13, 1217. G. A. Razuvaev, I . V . Lomakova, L. P. Stepovik, and V. K. Khamylov, J. Gen. Chem. (U.S.S.R.). 1973, 43, 1509. G. A. Razuvaev, I. V. Lornakova, and L. P. Stepikov, 1. Gen. Chem. (U.S.S.R.), 1973, 43, 2402. A. T. Weibel and J . P. Oliver, J. Organometallic Chem., 1974, 74, 155. F. Feher and R. Freund, Inorg. Nuclear Chem. Letters, 1974, 10, 561. F. Feher and R. Freund, lnorg. Nuclear Chem. Letters, 1974, 10, 569.

278

Inorganic Chemistry of the Main -group Elements Si,-Si, have been r e c ~ r d e d . ~A ” reinvestigation of the reaction between SiF, and HBr has shown that Si,F,H is not the major primary product, but results from the decomposition of SiF,HSiF,Br, which is itself the preponderant product of the reaction. A much more efficient synthesis of Si,F,H involves fluorination of the Si-Br bond in SiF,HSiF,Br with SbF,.”” Two new long-chain permethylsilanes, Me(SiMe,),Me (n = 18 and 24), have been obtained by the reaction of 1,6-dichIoropermethylhexasilane with methylmagnesium iodide, followed by addition of more dichlorohexasilane and potassium metal.5HoReductive coupling of t-butylmethyldichlorosilane using sodium-potassium alloy in THF gives low yields of 1,2,3,4-tetra-tbutyl-l,2,3,4-tetramethylcyclotetrasilane,as a mixture of two isomers.581 Several 1,2-substituted disilanyl compounds XMe,SiSiMe,X (X = H, C1, F, Br, I, OMe, Ph, o r SMe) and Si,Me,SMe have been prepared by standard substitution and cleavage methods.582The reaction of 1,2-dichlorotetramethyldisilane with RP(NMeH), (R = But o r OMe) yields the cyclophospha(1rI)disiladiazanes RP(NMeSiMe,),, which show no P inversion up to 180 “C. The Si-N bonds of Bu‘PCI(NMeSiMe,)=NSiMe, are cleaved by CIMe,SiSiMezCl with cyclization to give the cyclophospha(v)disilazene ButClP=N(SiMez)zNMe.583 Five-membered heterocycles Si,Ph,X (X = BNMe,, NMe, NEt, o r 0)have been prepared from octaphenyltetrasilane by initial lithiation or iodination followed by substitution. N o electron delocalization in any of the ring systems takes place.5R4 The tris(bipyridy1) complex [Si(bipy),]Br4 has been isolated from the products of the reaction of Si,Br, with 2,2’-bipyridyl. The complex consists of octahedrally co-ordinated [Si(bipy)3]4+cations and bromide anion5, and is not attacked by water, aqueous acid solutions, or methanol, but it is decomposed by alkaline The action of hexamethylphosphoramide o r phosphoric acid on the residues of the direct synthesis of methylchlorosilanes (which contain polysilanes) leads to a mixture of Me2SiCl2 and MeSiC13 in good yields. The action of ammonium phosphate on these residues affords a significant proportion of MeC1,SiH.”“ ‘x7 Application of the Woodward-Hoffman rules to the photolysis of polysilanes requires that the electronic transition be assigned to u + u* rather than the previously suggested u+ ~ ( 3 do r 4p).588 The ionization potentials of several 01 - and p -naphthyl and phenyl derivatives derived from chargetransfer spectra show that a silicon 3 p orbital is only one-third as effective t.. Feher and R. Freund, lnorg. Nucleur Chem. Letters. 1974, 10, 5 7 7 . J. F . Bald. K. G. Sharp, and A . G. McUiarmid. J. Fluorine C‘hcw.. 1974, 3, 433. W. G. Bobrrski and A. L. Allred, .I. Orgunometallic C’ktern.. 1974, 71, C 2 7 . 581 M. Biernbaum and R. West, .I. Orgunornetallic Chem.. 1974, 77, C1.3. ’‘’ E. Hengge and S. Waldhor, Monatsh., 1974. 105, 6 7 1. 0 . .I. Scherer, W. Glassel, and R. Thalaker, J. Orgunomrtullic Chern., 1974. 70, 61 ix4 E. Hcngge and D. Wolfcr. J. Organornetallic Chern., 1974, 66, 413. 5x5 D. Kurnmer and H. Koster, Z. anorg. Chern., 1973, 402, 297. ”’ R. Calas, J . Dunogues, and G. Deleris, J. Organornetallic Chem., 1974. 71, 37 1. i X 7 G. Deleris, J . Dunogues, and K. Calas, Bull. SOC. chim. France, 1973, 672. 5x8 H. G. Rarnsey, J. Orgunornetallic Chern.. 1974, 67, C 6 7 . 57x 57”

5xo

Elements of Group IV

279

as carbon or oxygen 2p orbital in overlapping with carbon .n-systems. The considerable u - r interaction seen in Si-Si .n-systems may be attributed to the very high energy of the Si-Si u - ~ r b i t a l . ,Reactions ~~ of (n-C5H5)(C0),MNa ( M = C r , Mo, or W) or (v-C,H,)(CO),FeNa with the halogenodisilanes Me,Si,X or Me4Si2X2(X = C1 or Br) yield disilanyl complexes of the type L,MSi,Me, or L,MSi,Me,X. AgBF, converts the chlorodisilanyl complexes into the corresponding fluoro-complexes. The interaction of pentamethyldisilanyl complexes with ylides results in metal -+ carbanion transfer of the Si-Si group through metal-silicon bond cleavage and transylidation. In the case of the halogenodisilanyl compounds, cleavage and transylidation occurs, involving both silicon-metal and siliconhalogen (r-C5H,)(CO)zFeCH,SiMe,SiMe, reacts with SO, to give the expected product of insertion into the Fe-C bond, and with PPh, to On pho to1ysis, how afford ( r-C5H,)(C0)Fe(PPh,)CO-CH,SiMe,SiMe,. ever, rearrangement of the skeleton [to (n-C,H5)(C0)2FeSiMe,CH,SiMe3in the absence of PPh, and (T~-C,H,)(CO)F~(PP~~)-S~M~,CH,S~M~, in the presence of PPh,] takes place. The latter product is also obtained by p ho tolysing mixtures of (r - C,H,) (CO),FeSiMe,CH,SiMe, and PPh,. 591 A number of pentamethyldigermane derivatives Me,GeGeMe,X (X = Br, I, CN, NO,, or NCS) have been prepared starting from the corresponding chloride. The compounds resemble the corresponding disilanyl derivatives, and the variation of substituent does not markedly affect the stability of the Ge-Ge bond.592 The Ge-Ge bond in hexakis(pentafluoropheny1)digermane, however, is very susceptible to attack, reacting with water, methanol, hydrogen chloride, acetic acid, trifluoroacetic acid, mercuric chloride, sulphur, and selenium. The reactions are very sensitive to the nature of the solvent and proceed in THF but not in non-polar solvents such as hexane, benzene, or toluene.593 Compounds of the general formula Ph,Sn,(O,CR), ( R = E t , Pr", Pr', But, CH,Ph, CPh3, SiPh3, or GePh,) have been prepared from diphenyltin dihydride and the appropriate carboxylic acid RC0,H. The complexes are monomeric in solution, and have structures in which carboxylate groups bridge both tin atoms of a tin-tin bond. The i.r. spectra of the silicon and germanium compounds are consistent with the existence of a ( d - p ) ~ bonding interaction between the silicon or germanium and the carbonyl oxygen atoms.5y4The oxidation of hexa-alkyldistannanes by tetracyanoethylene (tcne) and 7,7,8,8-tetracyanoquinodimethane(tcnq) results in the formation of complexes of the types R,Sn(tcne) and R,Sn(tcnq). H . Sakurai and M. Kira, J. Amer. Chem. SOC.,1974, 96, 791. W. Malisch, J. Orgartometallic Chem., 1974, 82, 195. "' K. H . Pannell and J . R . Rice, J. Organometallic Chem., 1974, 78, C35. "' A . J. Andy and J . S. Thayer, J. Organometallic Chem., 1974, 76, 339. sy-3 M. N . Bochkarev, G. A. Razuvaev, N . S. Vyazankin, and 0. Yu. Sernenov. J. Organometallic Chem., 1974, 74, C4. 5 y 4 G. Plazzogna, V. Peruzzo, and G. 'Iagliavini, J. Organometallic Chem., 1974, 66, 57. "" "'l

280

Inorganic Chemistry of the Main - group Elements

Hexaphenylditin is inert towards tcne, but with tcnq the complex (Ph,Sn),,tcnq is formed.S95Peloso has investigated the kinetics of the oxidation of hexaorganodistannanes by 1,1 0-phenanthroline, 2,2’-bipyridyl, and 2,2’,2”terpyridyl complexes of iron(^^^).'^^^'^' The reactions lead to the cleavage of the tin-tin bond with the concomitant reduction of two moles of the iron(ir1) complex per mole of distannane. The reactions obey a second-order rate law, first-order with respect to distannane and iron(ir1). The reactivity order of the organoditin compounds is Ph6Sn2< Me,SnSnPh, < Me6Sn, < Bu,Sn, for every iron(ir1) complex. The reactivity order of the iron(ir1) complexes parallels the order of the formal redox potentials of the complexes when the ligands bonded to iron(iii) are 1,lO-phenathroline, 5-nitro-, 5-methyl-, 5,6dimethyl-, or 3,4,7,8-tetramethyl-l ,lo-phenanthroline, or bipyridyl. For these, a linear relationship between the free energy of activation and the standard free-energy changes related to the actual electron-transfer step is observed, the slope being in reasonably good agreement with the theoretical prediction for the proposed outer-sphere redox mechanism. Asymmetric hexa-alkyldistannanes RiSnSnR: disproportionate under polar conditions rapidly at room temperature to give the symmetric distannanes RASn, and RiSn,. The equilibrium constants observed for a series of such reactions indicate the dominance of steric rather than inductive effects. The distannanes and similar digermanes react with acetylenes and diethyl a z o d i c a r b ~ x y l a t e .In ~ ~ strongly ~ co-ordinating solvents, e.g. THF, hexamethylditin reacts with dicobalt octacarbonyl to give not only Me,SnCo(CO),, which is the sole product in diethyl ether or pentane, but also a cobalt-carbonyl-catalysed disproportionation into Me,Sn and dimethyl~tannylene.”~The reaction between pentadeuteriophenyl-lithium and hexaphenyldilead, combined with isotopic exchange measurements on Ph,Pb, (labelled with RaD) and Ph,Pb, has shown that the dilead compound is undissociated in solution, thus casting doubt o n the supposed dissociative equilibrium: Ph,Pb, G Ph,Pb + Ph,Pb.hO” Tetracarbonylnickel reacts with tris(trimethylsily1)-, tris(trimethylgermy1)-, or tris(trimethy1stanny1)-stibine, yielding the corresponding tricarbonylorganometalstibinenickel complexes .601

Derivatives of Silicon, Germanium, Tin, and Lead containing Bonds to Transition Metals.-Derivatives containing Group IV metal-Transition metal bonds have in recent years been the subject of substantial activity. A 1 4

”‘’ iu7 iYX

5yy 600 611I

A. B. Cornwell, P. G. liai-rison, and J . A . Richardh, J. Orgutionwtullic Chrm.. 1973.67,C4.3. A . Pcloso, J. Organornetallic Chern.. 1974. 67,423. A. Peloso, J. Orgunornetallic C‘hern.. 1974,74, S9. b. J . Bulten and H. A. Budding, .I. Orgunomctallic C’hern., 1974, 78, 3x5. E. J. Bulten and H. A. Budding, J. Organornelallic Chern., l974, 82, 121. G . Plazzogna. V. Peruyfo, anti G. Tagliavini. J. Orgunometullic Chem., 1973, 60, 229. [ I . Schumann and H. J . Breunig, J. Organornekdlic Chern., 1974, 76, 2 2 5 .

Elements of Group N

28 1

large number of such derivatives have been synthesized by the substitution of the Group IV metal halide by a transition-metal carbonyl anion. The reactions of Na[Fe(C0),(C5H5)], Na[Mn(CO),], and Na[M(CO)3(C5H5)] (M = Mo or W) with various halogenosilanes and organohalogenosilanes have been studied by Malisch and Kuhn.h02Treatment of some of the complexes prepared in this way, L,MSiMe2H, L,MSiMeClH, and L,MSiCl,H [L,M = Fe(CO),(C,H,), M(CO),(C,H,) (M = Cr, Mo, or W), or Mn(CO),], with CCl, and CBr, yields the perhalogenated compounds L,MSiMe,Cl, L, MSiMe,Br, L, MSiMeCl,, and L, MSiC1,. Studies of the exchange rate suggested the operation of a free-radical mechanism for the halogenafi~n.~'~ Germanium complexes of the type Ph,-,Cl,GeM ( n = 1 or 2) are obtained by the reaction of the carbonyl anions [Mn(CO),]- or [Fe(CO),(C,H,)]- (M) with the appropriate phenylgermanium halide in THF. The analogous silicon derivatives are available uia the reaction of the appropriate phenylchloro- or pentafluorophenyl-silane with the transitionmetal carbonyl dimers. The reactivities of the compounds Ph3-,C1,M'M [ n = 1-3; M ' = Si, Ge, or Sn; M = Mn(CO), or Fe(CO),(C,H,)] towards pentafluorophenyl-lithium depend upon M, M', and the number of phenyl groups bonded to the Group IV metal. With M = Mn(CO),, the reactivity decreases in the order Sn == G e > Si. For M = Fe(C0),(C5H,), reaction occurred for all the tin complexes, but for M'= G e or Si only the trichloro derivatives undergo ~eaction.~", The sodium salts Na[RMe,C,Fe(CO),] react with Ph,SnCl to form RMe4C5Fe(CO),SnPh3 (R = Me or isopr~penyl).~'~ Garner has studied the displacement of the trifluoroacetate group from tin by carbonyl anions. Thus divinyltin bis(trifluoroacetate) undergoes salt elimination reactions with Na[Mn(CO),], Na,[Fe(CO),], and Na[Co(CO),] (CH,=CH)2Sn(0,CCF,)[Mn(CO)5], to afford the complexes (CH,=CH),Sn[Mn( CO),],, [(CH,=CH),SnFe (CO),], , and (CH,=CH),Sn[CO(CO),],."~ An additional product was also isolated from. the reaction with Na,[Fe(CO),] which was identified as the new iron-tin cluster system (36).607An approximate crystal structure of (CH,=CH),Sn[Mn(CO),],

W. Malisch and M. Kuhn, Cham. Rer., 1974, 107, 979. Malisch and M. Kuhn, Chem. Ber., 1974, 107, 2835. '"4 H. C. Clark and A. T. Rake, J. Organometallic Chem., 1974, 74, 29. '"'R. B. King, W. M. Douglas, and A. Efraty, J. Organometallic Chem., 1974, 69, 131. 'OZ

'" W.

282

Inorganic Chemistry of the Main -group Elements

Figure 24 The structure of trans -(Ph,Sn),Os(CO),. (Reproduced by permission from Inorg. Chern., 1974, 13, 1)

showed that the tin atom enjoys a distorted tetrahedral environment with LCSnC = 104(1)* and LMnSnMn = 115.7(4)'.'Oh Organotin complexes of tetracarbonylosmium have been synthesized by substitution of organotin halides by Na,Os(CO), and also by elimination reactions between the dihydride H,Os(CO), and organotin oxides, alkoxides, and amides. Stable trans complexes (R,Sn),Os(CO), were obtained €or R = P h and Bu. The structure of (Ph,Sn),Os(CO), is shown in Figure 24, and it is characterized by a linear Sn-0s-Sn linkage with r(Sn-0s) = 2.7 12 A. -Difunctional organotin compounds give di-p -tin complexes [(OC),OsSnBu,],. Phenyl groups o n tin co-ordinated to osmium are selectively cleaved by electrophilic reagents, giving halogenotin-osmium-tin complexes. Treatment of trans -(CIBu,Sn),Os(CO), with [Re(CO),] produces the pentametallic cornplex [(CO),ReSnBu,],Os(CO),. Attempts to prepare linear polymers from the collinear trans -(ClBu,Sn),Os(CO), gave only the di-F-tin complex [(CO),OsSnBu,]l.h"N Complexec of the serie\ C7H,Mo(CO)SnPh,,X, , (X = C1 o r Br; n = 0-3) have been prepared, employing a number of different synthetic methods, including C7H7Mo(CO),Br and LiSnPh, (n = 3 ) , C,H,Mo(CO),SnPh, and HCI ( n = 2 or 0; X = Cl), C,H,Mo(CO),SnCI, and Ph,Hg ( n = 1, X = Clj, and C,H,Mo(CO)?X and SnX, ( X = C1 or Br, n = 0). c'. D. Ciarncr arid H. Hughes. J.C.S. Dalton. 1973, 1306. C. D. Garner and R. G. Senior, Inorg. Nuclear C7hem. Letters. 1974, 10, 609. '"'J. P. Collman, D. W. Murphy, E. B. Fleischer, and I). Swift, Inorg. Chern., 1Y74, 13, I 609 H. E. Sasse. G. Hoch. and M. I.. Ziegler, Z. anorg. C'hem.. 1974. 406, 263. """ '("

Elements of Group IV 283 Photolysis of Me,N( 1,2-B,,HIoCHGe) and Cr(C0)6 in THF yields the complex Me," 1,2-B,,H,,CHGeCr(CO),], for which the structure in Figure 25 is proposed.610Derivatives of Mn(CO),, Mn(CO),(PPh,), and (C,H,)(CO),Fe containing the polysilyl ligands (Me3Si),,Me3-,,Si- (n = 1-3) have

L

I

Figure 25 Proposed structure of [1,2-B,,H,,CHGeCr(CO),]- ion (Reproduced by permission from J. Organometallic Chern., 1974,71,219)

been synthesized from the appropriate silyl-lithium reagent and Mn(CO),Br in THF.6" X,Pb[Mn(CO),], (X = C1 or Br) are obtained when phenyl groups are cleaved from Ph,Pb[Mn(CO),], by C1, or Br, in chloroform. The latter compound may be prepared by the salt method from Ph,PbCl, and NaMn(C0),.612 Trimeric [(CO),FeSiCl,], results from the interaction of Et4N [(CO),FeSiCl,] and AlCl,. The mass spectrum of the compound indicates that in the vapour phase both the dimeric species [(CO),FeSiCl,], and the monomeric silylene species (CO),FeSiCl, are present, in addition to the trimer. The Mossbauer spectrum exhibits resonances attributable to two

610 611

612

G . S. Wikholm and L. J . Todd, J. Organornetallic Chern., 1974, 71, 219. B. K. Nicholson and J. Simpson, J. Organometallic Chern., 1974, 7 2 , 211. H. J. Haupt, W. Schubert, and F. Huber, J. Organometallic Chern., 1973, 54, 231.

284 Inorganic Chemistry of the Main-group Elements types of iron atom, which are interpreted in terms of a mixture of isom e r ~ . The ~ ' ~ reaction of (C,H,)Fe(CO),SiCI, with amines in benzene or in pure amine gives the complexes (C,H,)Fe(CO),SiCI, JNR'R'), (R' = alkyl or aryl, R2= H or alkyl, x = 1-3). The value of x depends o n the basicity of the amine, and more importantly the steric requirements of the amine.'', Photolysis of Fe(CO), and Hg(SiMe,), leads to the formation of cis(OC),Fe(SiMe,), and Hg[Fe(CO),SiMe,],."" Carbonyl anions of iron, molydenum, and tungsten, [(C,H,)(CO),M]- ( n = 2 , M = Fe; n = 3, M = M o or W), react with vinylhalogenosilanes to afford the complexes (C,H,)(CO),MSiR,(CH=CH,) (R = Me or CI). The dichloro-complexes are converted into the corresponding difluorides by AgBF,, and into (C,H,)(CO),MSiF, by a further mole of AgBF,. The Fe-Si bond of the (C,H,)(COj,FeSiMe,(CH=CH,) complexes is cleaved by a number of reagents HX ( X = F , C1, Br, I, CF,COO, or CCI,COO), giving (C,H,)(CO),FeX and HSiMe,(CH=CH,)."" The Fe-Si bonds of the complexes Me,-, F, SiFe(CO),(C,H,) are cleaved by phosphorus ylides, giving the species [Me,PCH2SiF,Me, .][Fe(CO),(C,H,)], which reacts with further Me,P=CH,, affording [Me,P][Fe(CO),(C,H,)] and Me,P=CHSiF, Me,-,. The disilylated ylide Me,P=C(SiMe,), reacts with F,Si-Fe(CO),(C,H,j with exchange of Me,Si and F,Si groups, yielding Me,P=C(SiMe,)(SiF,) and Me,SiFe(CO),(C,H,)."" The reaction of the cationic complexes [(C,H,)Fe(CO),(cyclohexene)]+ and [(C,H,)Mo(CO),Y with (l72-GeCHB,,,H,,)forms the neutral complexes (C,H,)Fe(C0)2GeCHB,oH,,,and (C,H,)Mo(CO),GeCHB,,,H,,.''X The hydride (C,H,)Fe(CO)(CNMe)H engages in a base-catalysed reaction with Me,GeCl, and Me,SnCI to form the compounds (C5H,)Fe(CO)(CNMe)R (R = Me,ClGe or Me,Sn). The catalysis is proposed to proceed via base-induced deprotonation of the hydride to form the anion [(C,H,)Fe(CO)(CNMe)]-, which then reacts with the metal halides ."' The reactions of Me,SnCH,I with the sodium salts NaMo(CO),(C,H,), NaFe(CO),(C,H,), NaMn(CO),, and NaCo(CO), in THF d o not give the corresponding complexes Me,SnCH,M(CO), (C,H,), but instead tin-carbon bond cleavage occurs, resulting in the formation of the complexes Me,SnM(CO),(C,H,), ( M = M o , x = 3 , y = l ; M = F e , x = 2 , y = l ; M = M n , x = 5 , y = 0; M = Co, x = 4, y = O)."' The oxidative addition of the Si-H or Si-CI bonds to the low-valent complexes (Ph,P),Ni, (Ph,P),CoN,, (diphos),Ni, (diphos),CoH, (diphos)Fe(C,H and (dipho\) FeHl has been I)r

6. Schinid and ti. J . Balk, J . Orguriornetullic, C'hern., IY74. 80, 2 5 7 . M. Hiifler, J . Scheuren, and G. Weher. J . Organornetallic ('hem., lY7.1. 78, 3-47 ('" W. Jet/ and W. A . G. Graham. J . Orgunometullic ('hem.. 1974. 69, 3x3. "'" W. Malisch and P. Panster. J . Orgariorrlrrullic. ('hem., 1074. 64, c'5. I, I1 W. Malisch, J . Organornelallic Chem., 1074, 77, ('15. ,.IX I . Yaniamoto and L. J . Todd. J. Organornetallic Chern., 197.1, 67,7 5 . '"') R. D. Adarns, J. Orgunornetullic Chern., 1974, 82, C 7 . '"'' R. €3. King and K. C. Rhades, .1. Organornetallic Chem.. 1974, 65, 7 7 . ('I7

h 14

r

Elements of Group IV 285 investigated.62' The reactions of HC1, HBr, Cl,, I,, ICl, and CFJ with trimethyl-, triphenyl-, or phenyl(pentafluoropheny1)-Group IV metaltransition-metal derivatives containing M-Fe (M = Si, Ge, or Sn) and Sn-M' (M'=Mn, Cr, Mo, or W) bonds have been investigated by Clark. The reaction of HCl or HBr with complexes containing Sn-Fe or Sn-M' bonds, and of C1, with those containing Sn-Mn bonds, resulted in partial or complete replacement of the organic groups bound to tin. Cleavage of the metal-metal bond occurs in all other reactions.622The displacement of carbonyl anionic species from tin and lead by other transition-metal carbony1 anions has been studied. From the data it was concluded that the nucleophilic strengths of [Re(CO),]- and [Fe(CO),(C,H,)]- in T H F are c ~ m m e n s u r a t e . ~The ~ ~ reaction of 1,2-bis(dimethylsilyl)ethane with Fe(CO),, Ru,(CO),,, or O S ~ ( C O affords ) ~ ~ the chelate compounds (OC),FhSiMe2CH2CH2$iMe2(M = Fe, Ru, or 0s). The product with CO,(CO)~is [(OC),COS~M~&H,],.~~~ The hydrides R,MH (R = Me, M = Si, Ge, or Sn; R = E t , M = G e ) react exothermically with Co,(CO), at 20°C to yield the complexes R,MCo(CO), in high yield. The lighter Group IV element complexes may be converted into the corresponding derivative of a heavier element by treatment with the triorganometal hydride of the heavier metal. The Ge-Co bond in Me,GeCo(CO), is cleaved by HCl and HgCI,, and with NEt, or piperidine; tetracobaltate adducts Several other silyl-cobal t complexes have been synthesized by the reaction of Co,(CO), with the silyl hydride. Thus reaction with MeSiC1,H and Me,SiClH yields the complexes Me, SiC13-,Co(CO), (n = 1 or 2),"' and the complexes SiH2ClCo(CO),, SiH,[Co(CO),],, SiHCl,Co(CO),, Me2SiHCo(CO),, SiCl,Co,(CO),, SiH,CIMn(CO)s, SiH,[Mn(CO),],, SiCl,[Mn(CO),],, SiHClMn(CO),Co(CO),, and SiClMn(CO),Co,(CO), may be prepared by similar means from Co,(CO), or Mn(CO),H. The reaction between Fe3(C0)12 and SiHClMn(CO),Co(CO), yields the complex {Fe(CO),[SiClMn(CO),],}Co,(CO),."" The (T-cyclopentadieny1)cobalt complex (37) of tetrakis(trimethylsily1)cyclobutadiene has been prepared by the reaction of bis(trimethy1silyl)acetylene and the dinuclear cobalt complex di-v-cyclopentadienyl-~-bis(trimethylsilyl)acetylenedicobalt.628 The reactions of tetracarbonylcobalt-germanium and -tin compounds with diphenylacetylene, p diethynylbenzene, and pbis(phenylethyny1)benzene have been studied, and under U.V.irradiation both Co-CO and M-Co bonds are broken. The M . F. Lappert and G. Speier. J . Organornetallic Chern., 1Y74, 80, 329. Bichler. H . C. Clark, B. K . Hunter, and A. T. Rake, J. Organornetallic Chern., 1974, 69, 367. "' A. N. Nesmeyanov, N . E. Kolobova, V. N . Khandozhko, and K. N. Anisimov, J. Gen. Chem.

"' R. E. J.

(U.S.S.R.), 1074, 44, 298. L. Vancea and W. A. Graham, Inorg. Chem., 1974, 13, 511. G . F. Bradley and S. R. Stobart, J.C.S. Dalton, 1974, 264. "' A. P. Hagen, L. McAmis, and M. A . Stewart, J. Organometallic Chem., 1974, 66,127. 627 K. M. Abraham and G. Urry, Inorg. Chem., 1973, 12, 2850. 6 2 8 H. Sakurai and J. Hayashi, J . Organometallic Chem., 1974, 70, 85.

624

286

Inorganic Chemistry of the Main -group Elements

Me,Si

SiMe,

Me,Si

SiMe,

complexes Ph,C,Co,(CO), and [CO,(CO)~]~(C~R),C,H, (R = H or Ph) were isolated from the reaction The reversible 'ring-opening' reaction of the complex {(OC),Co(pG~P~,)(~-CO)CO(CO with ) ~ } carbon monoxide in decalin to form ( p GePhz)(Co(CO),}, proceeds by a path that is first-order in [complex] and [CO], and the reverse reaction is first-order only in [complex]. The reaction with PPh, forms the complex ( p-GePh,)(Co(CO),(PPh,)},, probably via {(0C) Co (p - G ePh2)(p -CO)Co (CO),(PP h3)},produced in a rate -determining CO-dissociative process and subsequently attacked by a second phosphine molecule in a rapid ring-opening reaction. Bimolecular attack by PPh, also occurs, and leads directly to the complex ( p-GePh,)(Co(CO),(PPh,)}{Co(CO),}. The reaction of the latter complex with PPh, produces ( p GePh,)(Co(CO),(PPh,)} by a process which is first-order only in [comp l e ~ ] . ~The ~ ' photolysis of the complexes Me,GeM, [M=Co(CO), or Fe(CO),(C5H5)] proceeds with the loss of one CO followed by ring closure to give complexes with the structural unit (38). Photolysis of Me2Ge-

[Mn(CO),], affords the complex (Me,Ge)Mn,(CO),, which in solution apparently exists in a form not containing a bridging carbonyl group. The exposure of Me,Ge[Mo(CO),(C,H,)], to light results in the rupture of the Ge-Mo bond, giving [(C,H,)Mo(CO),], or (CSH,)Mo(C0),, depending on the solvent. The photolysis of the chlorogermanium complexes Me,Ge(Cl)M [M = Mn(CO),, Co(CO),, Fe(CO),(C,H,), Mo(CO),(C,H,), or Cr(CO),(C,H,)] results in the formal loss of chlorine and CO, with subsequent dimerization to give complexes of the type (39).631The vinylgermanium-transition-metal derivatives (CH,=CH)Me,GeM [M = Mn(CO),, Mo(CO),(C,H,), Co(CO),, Fe(CO),NO, Co(CO),NO(CN), 629

'")

A . N . Nesmeyanov, K. N . Anisimov, N. E. Kolobova, and V. N . Khandozokho. J. Gen. Chem. (U.S.S.R.). 1974, 44, 302. M. Basato, J. P. Fawcett, and A. Poe, J.C.S. Dalton, 1974, 1350. R . C. Job and M. D. Curtis, Inorg. Chem., 1973, 12, 2514.

Elements of Group IV

287

Fe(CO),(C,H,), Mn(CO),PPh,, or Co(CO),PPh,] have been synthesized by treating the vinylgermanium halide with the appropriate carbonyl anion. Their photolyses proceed with the rupture of the Ge-M bond to give complex mixtures from which compounds such as (C,H,),Mo,(CO),, E.L-carbonyl-~-dimethylgermyl-bis(cyclopentadienylMn,(CO),,, and carbonyliron) may be isolated.632When dilute hydrochloric acid is added to the lithium salt of the anion cis-[Ph,GeMn(CO),C(O)Me]- in water, a phenyl group is cleaved from germanium to produce a colourless solid of formula Ph,GeMn(CO),COMe. The trimethylgermyl analogue reacts similarly, and the complexes were formulated as the carbene complexes R,GeMn(CO),C(O)Me on the basis of spectroscopic evidence .633 More detailed n.m.r. studies have shown that the monomeric species is in equilibrium with its dimer, and although it was not possible to obtain single crystals of the manganese derivative, the structure of the rhenium analogue (Figure 26) has been determined. The molecule contains an unusual eightmembered heterocyclic ring of rhenium, germanium, oxygen, and carbon r(Ge-0) = 1.96(2) A, LReGeO = atoms; r(Ge-Re) = 2.591(3), 107.6(4)0.634

Figure 26 The structure of [Me,GeRe(CO),C(O)Me], (Reproduced by permission from J. Arner. Chern. SOC., 1974, 96, 5931) 632

h33 b34

R. C. Job and M. D. Curtis, Inorg. Chem., 1973, 12, 2510. M . J . Webb, R. P. Stewart, and W. A. G . Graham, J. Organometallic Chem., 1973, 59, C21. M. J. Webb, M. J. Bennett, L. Y . Y . Chan, and W. A. G. Graham, J . Amer. Chem. ‘Soc., 1974, 96, S931.

288

Inorganic Chemistry of the Main-group Elements

Figure 27 Projection of the unit cell of di-p-dirnethylstannylenebis (carbonylT -c yc lope n tadien y 1cobalt) (Reproduced from J.C.S. Dalton, 1973, 1060) Crystals of di-~-dimethylstannylene-bis(carbonyl--rr-cyclopentadienylcobalt) contain two crystallographically independent molecules, which only differ in their orientation in the unit cell. Tin and cobalt atoms alternate around a four-membered ring, the tin atoms having slightly distorted tetrahedral co-ordination and the cobalt atoms octahedral co-ordination if the cyclopentadienyl rings occupy three sites (Figure 27); r(Sn-Co) = 2.542(2), r(Sn-C) = 2.20(1) LSnCoSn = 78", LCoSnCo = 101.3°."5 Cotton et al. have investigated the molecular structure of (C5H,),Fe,(CO),(GeMeJ in the solid by X-ray diffraction and the structural and dynamic properties in solution by i.r. and 'H and "C n.m.r. spectroscopy. The structure in the solid is shown in Figure 28. The molecule has a bridging Me,Ge group and is the cis-isomer of (q 5-C,H,),Fe2(CO),(p-CO)(pGeMe,). Each bridging group is symmetrical. In solution at 25 "C there is a n approximately 8 :1 cis-trans mixture, with the isomers interconverting too slowly to influence either the 'H or "C n.m.r. spectra, but between 90 and 160°C the signals for both q5-C5H5and Me groups collapse and coalesce. The results were rationalized by a concerted opening of the two bridges, leading to a non-bridged intermediate, which may undergo internal rotation

A,

h35

J . Weaver a n d P Woodward, J.C.S. Dulton, 1973, 1060.

Elements of Group IV

289

Figure 28 The structure of cis -(q s-C,H,),Fe,(CO)2(p-CO)(p -GeMe,) (Reproduced by permission from Znorg. Chem., 1974, 13, 1080)

and then re-establish bridges. The relatively high activation energy of ca. 21 kcal mol-' deduced for the process is attributed to the relative instability of the intermediate which contains a terminal dimethylgermylene ligand.636 One of the main oxidation products of this compound has been shown to be [(q5-C5H,)(CO),FeGeMe2],0,also by X-ray diffraction. The structure is shown in Figure 29, and consists of two [(q 5-C,H5)(CO),FeGeMe,] moieties joined by an oxygen atom [r(Fe-Ge) = 2.372, r(Ge-0) = 1.785 A; LGeOGe' = 134'1. In polar solvents the n.m.r. spectrum suggests the existence of major and minor conformers that are only slowly interconverting on the n.m.r. time-scale at ca. 25 OC."'

Figure 29 The structure of [(C,H,)(CO),FeGeMe,],O (Reproduced by permission from J. Organometallic Chem., 1974, 73, 93)

637

R. D. Adarns, M. D. Brice, and F. A. Cotton, Inorg. Chem., 1974, 13, 1080. R. D. Adarns, F. A. Cotton, and B. A. Frenz, J. Organometallic Chem., 1974, 73, 93.

290 Inorganic Chemistry of the Main- group Elements The reaction of Ni(CO), with t-butyl-tetrafluorodisilacyclobutene in a sealed tube at room temperature yielded a fraction which contained (40) as

(40)

the major product together with a small amount of I

Bu'C=HC-SiF,-Ni(

I

CO),-SiF,

.638

The Si-Ni complexes Ni(bipy)(SiX,), (X, = C1 or MeC1,) and Ni(C5H,)(PPhJ(SiC1,) are obtained by the reaction of hydrosilanes with the appropriate alkylnickel complexes Ni(bipy)R, (R = Me or Et) and Ni(C5H5)(PPH,)Et, respectively. Both types of complex react with H(D)Cl to give the corresponding chlorosilane and Ni(bipy)Cl,. Ni(bipy)(SiMeCl,), reacts with tetracyanoethylene to yield MeCl,SiSiCl,Me in low yield .63y Ni(bipy)(SiCl,), with diphenylacetylene ,yields the violet complex [trans a,a'-bis(trichlorosilyl)stilbene]bipyridylnickel(o). Treatment of this compound with MeMgI followed by hydrolysis afforded free trans -a,a'-bis(trimethylsily1)stilbene. Similar reactions with other acetylenes generally gave cisltrans mixtures of The stability to dissociation of silyl-rhodium complexes of the type L,RhH(SiR,)Cl (L = phosphine, R = OEt, Me, or Et) has been investigated for a wide range of ligands L and SIR, . 6 4 1 Stone has obtained pentalenyl and pentalene complexes of ruthenium by the reaction of all-trans -cyclododeca-l,5,9-trienewith tetracarbonylbis(trimethylgermy1)ruthenium. The two pentalenyl complexes obtained in this way, Ru(GeMe,)(CO),(C,H,) and Ru,(GeMeJ( p-GeMe,),(CO),(C,H,), are also formed in the reaction between cyclo-octa-l,5-diene and (CO),(Me,Ge)Ru, but the major product of this reaction is the cyclo-octa-1,5diene complex Ru(GeMe,),(CO),(C8Hl,). Similar reactions occur with Ru(SiMe,),(CO), and the dinuclear complexes [Ru(CO),(MMe,)], (M = Si or Ge).642An isomeric mixture of cyclo-octa-1,3,5- and -1,3,6-trienes reacts with Ru(SiMe,),(CO), and [Ru(SiMe,)(CO),], to give the non-siliconcontaining products Ru2(C0)6(CSHl,)and Ru(CO),(CsH,,) as major products, together with the tetrahydropentalenyl complex Ru(SiMe,)(CO)2(CeH9).The germanium analogues undergo Ge-Ru bond cleavage less h3X 639 h40 64' 642

C. W. Cheng and C. S. Liu, J.C.S. Chern. Cornrn., 1974, 1013. Y. Kiso, K. Tamao, and M. Kumada, J . Organometallic Chern., 1973, 76, 95. Y. Kiso, K . Tamao, and M. Kumada, J . Orgunometullic Chern., 1973, 76, 105 R. N. Haszeldine, R. V. Parish, and R. J . Taylor, J.C.S. Dalton, 1974, 23 1 1 . S. A. R. Knox, R. P. Phillips, and F. G. A. Stone, J.C.S. Dalton, 1974. 6 5 8 .

Elements of Group IV

291

readily and react with the C,H,, mixture to give the pentalenyl complex Ruz(GeMez)(F-GeMe2)2(C0)4(C,H9)as the major The cycloheptadienyl complexes RU(MM~,)(CO)~(C,H,MM~,) (M = Si or Ge) are formed on reaction of cycloheptatriene with Ru(MMe,),(CO),. An X-ray(Figure 30) has esdiffraction study of Ru(SiMe,)(CO),C,H7(C6F5)(SiMe3) tablished an ex0 -configuration for the migrant SiMe, group.644Hydrosilanes react with RuH,(PPh,), to give apparently seven-co-ordinate RuH,(SiR,)(PPh,), complexes.645

Figure 30 The structure of Ru(SiMe,)(CO),C,H,(C,F,)(SiMe,) (Reproduced from J.C.S. Chem. Comm., 1974, 673) The reaction between two moles of Hg(SiMe,), and PtCl,{(Ph,P),CH,} gives the complex Pt(SiMe,),{(Ph,P),CH,}, whilst with a deficiency of Hg(SiMe,), the bright red PtrV complex Pt(HgSiMe3),(SiMe,),{(Ph2P)2CH,} is formed. This latter compound slowly decomposes, to afford the former Pt" complex, Me6Si,, and mercury.646Eaborn et al. have studied in detail the stereochemistry of the formation and cleavage of silicon-platinum bonds. Optically active complexes with asymmetric silicon atoms are formed with retention of configuration at silicon by the reaction of R,Si*H and cisPtCl,(PMe,Ph) or Pt(PPh,),C,H,. The R,Si*H may be regenerated with retention of configuration using lithium aluminium hydride. The stereochemistries of the reactions of the complexes with PhSH, EtSH, Br,, LiBr, NaI, PhCOC1, and PhC,H were also studied. It was inferred that reactions involving cleavages of the Si-Pt bonds in the complexes probably h43 644

645

646 647

A. C. Szary, S. A. R. Knox, and F. G . A. Stone, J.C.S. Dalton, 1974, 662. J . A. K. Howard, S. A. R. Knox, V. Riera, B. A. Sosinsky, F. G . A. Stone, and P. Woodward, J.C.S. Chem. Comm., 1974, 673.H. Kono and Y. Nagai, Chem. Letters, 1974, 931. F. Glockling and R. J. I . Pollock, J.C.S. Dalton, 1974, 2259. C. Eaborn, D. J. Tune, and D. R. M. Walton, J.C.S. Dalton, 1973, 2255.

292

Inorganic Chemistry of the Main- group Elements 0 7 r

0.1

I 0

1

-

1

L

Figure 31 Projection of the structure of Cl,GeCo(CO), (Reproduced by permission from J. Organometallic Chem., 1974, 80, 3 6 3 ) occur via oxidative-addition-elimination sequences, with complete or almost complete retention of configuration at silicon, any losses of optical activity arising from secondary reactions.647Fluorine-1 9 n.m.r. studies of fluorophenylsilyl-platinum complexes indicate that the Ph,Si group acts as a good a-donor and a good .rr-acceptor when bonded to platinum.64RRankin et aE. have reported 'H, "P, and 195Ptchemical shifts and a number of coupling constants for a wide range of silyl- and germyl-platinum comp o u n d ~ The . ~ ~ stannyl-platinum ~ complex PtH(SnCI,)(PPh,), catalyses the isomerization of pent-1-ene to pent-2-ene in benzene at 80 0C.65" 6.w

64')

""

C . Eahorn, M. R. Harrison, P. N . Kapoor, and D. R. M. Walton. J. Orgunometullic Chem., 1973. 63, 99. D. W. W. Anderson, E. A. V. Ebsworth, and D. W. H. Rankin, J.C.S. Dalton, 1973, 2370. D. Bingham. D. E. Webster, and P. B. Wells, J.C.S. Dalton. 1974. 1514.

Elements of Group IV

293

Several physical and structural studies of trihalogenometal(rv) derivatives have appeared. The vibrational spectra of X,MMn(CO), (X= C1, Br, or I; M = Si, Ge, or Sn),651,652 Me,MM'(CO), (M = Ge or Sn; M' = Mn or Re) and Cl,SnMn(CO),,"" [X,MFe(CO)J (X = C1 or Br; M = Ge or Sn) anions:54 and X,GeCo(C0)4 X,MCo(CO), (X = C1, Br, or I; M = Si, Ge, or Sn),655.656 (X= H, D, or F)656,657 have been measured, and in several cases normal-coordinate analyses have been performed. The crystal structure of Cl,Ge(CO), has been determined and contains two inequivalent molecules in the unit cell, both of which exhibit slight deviations from C3usymmetry. The co-ordination at cobalt is trigonal-bipyramidal and that at germanium tetrahedral. The equatorial carbonyl groups are in a staggered conformation with respect to the C1,Ge residue, with the carbonyl groups tilted towards germanium (Figure 31). The mean Ge-Co bond distance of the The [Pt(GeCl,),]- anion is a distorted trigonal two molecules is 2.31 A.658 bipyramid with equatorial Pt-Ge distances of 2.424(3), 2.399(3), and 2.480(3)A and axial Pt-Ge distances of 2.410(3) and 2.391(3)A. The bond angles in the equatorial plane are 111.0, 141.5, and 107.4", and thus

Figure 32 The immediate co-ordination sphere of the iridium atom in (C,H,)(Me,PhP),IrSnCl, (Reproduced by permission from J. Arner. Chern. SOC., 1974, 96, 76)

h51 652 h51 654

655

h56 657 658

S. Onaka, Bull. Chem. SOC. Japan, 1973, 46, 2444. S. Onaka, J. Inorg. Nuclear Chem., 1974, 36, 1721. A. Terzis, T. C. Strekas, and T. G. Spiro, Inorg. Chem., 1974, 13, 1346. W. M. Butler, W. A. McAllister, and W. M. Risen, Inorg. Chern., 1974, 13, 1702. G. C. van den Berg, A. Oskram, and K. Vrieze, J. Organornetallic Chem., 1973, 57, 329. G. C. van den Berg, A . Oskram, and K. Vrieze, J. Organornetallic Chem., 1974, 69, 169. G. C. van den Berg and A . Oskram, J. Organornetallic Chern., 1974, 78, 357. G. C. van den Berg, A. Oskram, and K. Olie, J . Organornetallic Chem., 1974, 80, 363.

294

Inorganic Chemistry of the Main-group Elements

this anion is more severely distorted than its tin analogue.659The structure of norbornadienebis(dimethylphenylphosphine)(trichlorostannato)iridium(r) has been determined, and the immediate co-ordination sphere about the iridium atom is shown in Figure 32. The co-ordination at iridium is midway between trigonal-bipyramidal and square-pyramidal, with the SnC1, group axial. The Ir-Sn distance is 2.5867(6)A and the Sn-C1 distances are 2.391(2), 2.409(2), and 2.417(2)A. The ClSnCl bond angles fall in the range 93.96(8)-97.60(7)".660 The tin-1 19 Mossbauer data for a large number of SnCl, derivatives of transition metals have been measured, and have been rationalized by considering the donor ability of L in the complex LSnCl,."'

Bivalent Derivatives of Silicon, Germanium, Tin, and Lead.- Unstable Silylenes and Germylenes. ["SiISilylene adds to buta-l,3-diene to give r1Si]silacyclopent-3-ene. Studies using nitric oxide as a scavenger demonstrate that the reacting silylene is present as 80% triplet and 20% singlet, while studies using neon as a moderator prove that the ground electronic state of silylene is a ~ i n g l e t . ~The ~ ' , ~stereochemistry ~~ of the addition of silylene to such systems has been investigated by studying the reaction with trans-2-trans -4-hexadiene. This reaction yields equal amounts of both cis and trans -isomers of 2,5-dimethyl-1-silacyclopent-3-ene, and a mechanism involving the intermediate formation of a biradical or a vinylsilacyclopropane was An alternative mechanism for the formation of disilahexadienes from the reaction of silylenes and acetylenes has been proposed. In this mechanism, a 1,2-disilacyclobutadiene is formed by the addition of a second silylene to the double bond of the initially generated silacyclopropene. The final Droduct is then obtained b-v- _t@-J2ie!s,A,ldpJ silylene and a silane. In MeHClSiSiClHMe, the relative rate of the 1,2 hydrogen shift is 4.4 times greater than the 1,2 chlorine shift, but 1,l halogen shifts were not observed in l,l-F2SizH4or 1,1-Cl2SiZH4.The relative rates for silylene insertion into the Si-H bond of ethylsilane are in E. I). Estes and I). J. Hodgson. Inorg. Chem., 1973, 12, 1932. M. R. Churchill and K. K. G. Lin, 1. Amer. Chem. Soc., 1974, 96, 76. '" M. J. Mays and P. L. Sears, J.C.S. Dalton, 1974, 2254. '" 0. F. Zeck, Y. Y. Su, G . P. Gennaro, and Y. N. Tang, J. Amer. Chem. Soc.. 1974,96,5967 h''3 P. P. Gaspar, R. J . Hwang, and W. C . Eckelman, J.C.S. Chem. Comm., 1974, 242. 6h4 P. P. Gaspar and R. J. Hwang, J. Amer. Chem. SOC.,1974, 96, 6198. ''' T. J . Barton and J. A. Kilgour, J. Amer. Chem. Soc., 1974, 96, 7 150. "' M. D. Sefcik and M . A. Ring, J. Organometallic <-hem., 1973. 59, 167. Ds''

'"'

Elements of Group IV

295

the order SiH, > ClSiH > FSiH >> Cl,Si, F,Si.667The photoelectron spectrum of SiF, has been measured and the electronic structure discussed in The substituted germylenes Ph(PhC1,Ge)Ge: and Ph[Ph(MeO),Ge]Ge: have been characterized in the decomposition of the trigermanes PhX,GeGe(X)(Ph)GeX,Ph (X = Cl or OMe) by condensation with dimethylbutadiene to form germylgermacyclopentenes. The photolysis of the tetragermanes (PhX,Ge),GePh (X=C1 or Me) leads to the germylenes Ph(PhC1,Ge)Ge: and Ph(PhMe,Ge)Ge:. The latter compound may also be obtained from the photolysis of the mercurial [(PhMe,Ge)Ge(Ph)Hg],.669

Halogen Derivatives. Vibrational spectra for both monomeric GeF, and dimeric (GeF,), have been obtained in nitrogen matrices. The data for the The addition dimer indicate a centrosymmetric,, non-planar C,, of trichlorogermane to 1,3-benzothiazol-2-yltrimethylsilane results in quantitative addition to the C=N bond, forming 2,3-dihydro-2-trimethylsilyl-2trichlorogermylbenzothiazole, which decomposes at 9 1"C, liberating Me,SiCl and forming the hydrolytically and thermally stable dichlorogermylene-benzothiazole complex. The analogous dichlorogermy1ene-Nmethylbenzimidazole complex was obtained similarly. The complexes are monomeric, and the structure of the former is shown in Figure 33. The bond angles at the three-fold co-ordinate germanium are all close to 90°, whilst the Ge-N bond distance is 2 . 0 9 2 A and the mean Ge-Cl distance 2.258 81.67',67A The insertion of dichlorogermylene (derived from the dioxan complex) into the C-C1 bond of a number of substituted benzyl chlorides has been the subject of a kinetic study. The reaction is first-order in benzyl

Figure 33 The structure of 3-dichlorogerrnylene-1,3-benzothiazole (Reproduced by permission from Angew. Chem. Internat. Edn., 1973, 12, 1002) 667

66R boy

670 67'

672

R. L. Jenkins, A. J. Vanderwielen, S. P. Ruis, S. R. Gird, and M. A . Ring, Inorg. Chem., 1973, 12, 2968. T. P. Fehlner and D. W. Turner, Inorg. Chem., 1974, 13, 754. P. Riviere, J. Satge, and D. Soula, J . Organornetallic Chem., 1973, 63, 167. H. Huber, E. P. Kiindig, G. A. Ozin, and A. Vander Voet, Canad. J . Chern., 1974,52, 95. P. Jutzi, H. J . Hoffman, and K. H. Wyes, J . Organornetallic Chem., 1974, 81, 341. P. Jutzi, H. J. Hoffman, D. J . Brauer, and C. Kruger, Angew. Chern. Internat. Edn., 1973, 12, 1002.

296

Inorganic Chemistry of the Main-group Elements chloride, but t h e rate also depends o n the dissociation of the GeCl,,dioxan complex.673Tri-iodogermane has been prepared by condensing HI onto anhydrous GeI,. The resulting pale yellow solution is stable below -50 "C, but gradually decomposes at room temperature to GeI, and H,."' The oxidation of SnF, in HF with 0,,F,, o r SO, yields the mixed-valence fluoride Sn,F,. The structure of this compound is shown in Figure 34, and it consists of trans -fluoride-bridged SnIVF6 units linked to polymeric

Figure 34 The structure of Sn,F, (Reproduced from J.C.S. Chem. Cornrn., 1973, 944) {Sn"F}, chains.675The crystal structure of Sn,F,CI consists of pyramidal SnF, groups linked through common fluorine atoms, with chlorine atoms occupying large holes to form a three-dimensional The i.r. spectra of polycrystalline samples of K,SnCl,,H,O"" and KSnC1,,H,0678 with varying degrees of deuteriation have been recorded at temperatures between 30 and -1 60 "C. In K,SnCl,,H,O, the water molecules are all equivalent and asymmetric, and are sufficiently well separated from one another for dynamic coupling of vibrations to be negligible. Both hydrogen atoms of the molecule take part in hydrogen bonding, although one of the hydrogen

"' 0. M. Nefedov. S. P. Kolesnikov,

B. L. Perl'muttrr, and A . I . loffe. Doklady C'heni., 1973, 211, 5.30. F. Honer and E. Brandstiitter. Angew Chern. Internat. Edn.. 1973, 12, 856. "' M. F. A . Dove, R. King, a n d T. J. King, J.C.S. Chem. Comni., 1973, Y44. G . Bergcrhoff and L. Goost, Acta Cryst., 1974, B30, 1362. "' M. Falk. C. H. Huang, and 0. Knop, Canad. J. Chem.. 1974, 52, 2380. 'I7'

Elements of Group IV 297 bonds is weak and The spectra for KSnCl,,H,O are complex and indicate the presence of several different water molecules. These molecules occupy sites with nearly identical environments, and at room temperature they are spectroscopically indistinguishable. Hydrogen bonds in the system are very weak and probably highly bent.678Donaldson et al. have recorded the vibrational spectra in the tin-halogen stretching and deformation region for a large number of SnX; and Sn,Xi species (X = C1 or Br).679Tin(r1) chloride and bromide react with tetracyanoethylene in THF to form adducts of composition S ~ X , , ~ C ~ ~ , T Tin(I1) H F . chloride ~~~ forms adducts of composition SnC1,,2donor with di-2-pyridyl ketone, NNdimethylpropane-l,3-diamine,3,3'-diaminodipropylamine, and 1,4-bis(3aminopropyl)piperazine, but with 1,lo-phenanthroline, an adduct of composition (SnCl,),,phen is obtained.681Chloromethylsilanes react readily with tin(1r) chloride in diglyme at 165°C to form high yields of trichloro(silylmethy1)stannanes R3SiCH,SnC1,.682 The electron-exchange reaction .between SnII and U"' is overall second-order for all HC1 concentrations. The rate of the reaction and the Arrhenius parameters are periodic functions of the hydrogen ion concentration. The reaction is catalysed by iron(m) and copper(n) by a process involving one-electron reduction of U"1.683The compositions and stability constants for halogeno- and thiocyanato-complexes of tin(Ir) and lead(1r) in DMSO have been determined by potentiometry. For both metals the stability of the complexes increases in the order NCS < I < Br < Cl.""" has been determined. The crystal structure of (q6-C6H6)Pb(A1C14),,C6H6 The local enivironment of the Pb" is that of a distorted pentagonal bipyramid with an axial site occupied by the centre of a benzene ring (Figure 35). The second benzene molecule is a molecule of solvation, far removed from the metal. The overall structure is described as a chain in which AICli tetrahedra are bridged together by Pb" and the other AlCl; behaves as a chelating ligand to form an axial and an equatorial Pb-Cl bond. The Pb-Cl bond distances vary from 2.854(8) to 3.218(9)A. A qualitative MO model adequately accounts for many of the Pb" coordination features.68SThe vibrational spectra of the lead(rr) fluoride halides PbFX (X = C1, Br, or I) have been recorded, including Raman polarization data obtained for single crystals of PbFCl.686Solid-state phase transformations involving basic and long-period lead(1r) iodide polytypes have been

'" M . 679 6x0

hn I 682

hX3

684

685 hR6

Falk, C. H. Huang, and 0. Knop, Canad. J. Chern., 1974, 52, 2928. S. R. A. Bird, J. D . Donaldson, S. D. Ross, and J. Silver, J . Inorg. Nuclear Chem., 1974, 36,

934. J. A. Richards and P. G. Harrison, J. Organometallic Chem., 1974, 64, C 3 . D. L. Perrv and R. A. Geanangel, J . Inorg. Nuclear Chem., 1974, 36, 205. V. F. Mironov, V. I. Shiryaev, V. V. Yankov, A. F. Gladchenko, and A. D. Naumov, J. Gen. Chem. (U.S.S.R.),1974, 44, 776. R. T. Mathew and E. S. Amis, J. Inorg. Nuclear Chem., 1973, 35, 4245. V. M. Samoilenko and V. I. Lyashenko, Russ. J. Inorg. Chem., 1973, 18, 1271. A. G. Gash, P. F. Rodesiler, and E. L. Amma, Inorg. Chem., 1974, 13, 2429. A. Rulmont, Spectrochirn. Acta, 1974, 30A, 161.

298

Inorganic Chemistry of the Main -group Elements

Figure 35 The local environment of the lead(r1) atom (c,H6)pb(A1c1,),7c,H6 (Reproduced by permission from Inorg. Chem., 1974, 13, 2429)

in

i n v e ~ t i g a t e d . ~The ~ ' crystal structure of RbPbI, has been determined and contains nearly octahedrally co-ordinated lead. T h e PbI, octahedra are arranged in the form of double chains along the crystal c-axis, which are held together by rubidium atoms. The Pb" lone pair is stereochemically inactive.688 A number of etherates of bromo-acids of lead(ir), viz. H5(PbBr,),8Et,0, H,(PbBr6),6Et,0, H,(PbBr5),4Et,0, H(PbBr,)E t 2 0 , and H(Pb2Br,),2Et,0, have been ~ r e p a r e d . ~ *The ~ equilibrium PbCl,(g) +ThCL(g) PbThCl,(g) has been studied by mass spectrometry, using the Knudsen effusion method. AHo (298) has been determined to be (-32.0 kcal rn01-l.~~'The affinity for co-ordination with Pb" of chloride, bromide, and nitrate ions in molten dimethyl sulphone has been deduced to be C1- > Br- >> NO;.691The competition between chloride, bromide, and sulphate for Pb" in glass systems has also been studied. With chloride and bromide present, mixed co-ordination spheres occur, but with sulphate present Pb2+tolerates mixed co-ordination spheres much less r e a d i l ~ . " ~

Oxygen Derivatives. The low-temperature form of tin(11) tungstate SnWO, is stable below 940°C. It is dark red, diamagnetic, and semiconducting, and the structure in the crystal may be considered as consisting of sheets of (W0,)'- polyanions separated by Sn" cations. Both "" 688

689 69 1

'''

R. Prasad and 0. N . Srivastava, Actu C'ryst., 1974, B30, 1748. H. J . Haupt, F. Huber, and H. Preut, Z. unorg. Chem., 1974, 408, 2 0 9 A. Galinos and I. Triantafillopouiou, Monatsh., 1973, 104, 1534. M. Binnewies and H. Schiifer, Z . anorg. Chem., 1974, 410, 149. J. A. Duffy and M. D. Ingram, J . Inorg. Nuclear Chem., 1974, 36, 39. J . A. Duffy and M. D. Ingram, J . Inorg. Nuclear Chem., 1974, 36, 43.

Elements of Group IV

299

metals have distorted octahedral co-ordination, with Sn-0 bond distances ranging from 2.18 to 2.83A.693A series of pyrochlore compounds of Pb(Ti,,Snl-,)03 have been prepared in aqueous media, and have inhomogeneously distributed Ti and Sn ions in equivalent lattice positions. The thermal transition from the pyrochlore-type Pb(Ti0.4-Sn0.6)03 to the perovskite-type system occurs preferentially at Ti-rich micro-regions in the matrix lattice, in which a measurable fluctuation of the Sn:Ti ratio can be dete~ted.~'" The solubility limits and the symmetry of solid solutions in complex lead oxide systems with the perovskite structure have been determined.69sThe crystal structures of lead trititanate PbTi;O, and lead metavanadate PbV206 have been determined. PbTi,07 crystals contain Ti06 octahedra which are connected to each other by corner- and edge-sharing to form a three-dimensional network of the composition Ti,O,. The lead atom is surrounded by seven oxygen atoms, with Pb-0 distances of PbV,O, has two distinct vanadium atoms, each between 2.36 and 3.04 A.696 co-ordinated to five oxygen atoms. The distorted V 0 6 octahedra are completed by a sixth much longer V-0 bond. The lead ion is co-ordinated to nine oxygen atoms lying in a spherical shell with inner and outer radii of 2.56 and 2.90 A.."" The binary compounds PbO.,WO3, 2Pb0,W03, 4Pb0,Bz03, 2Pb0,Bz03, 5Pb0,4B,03, and Pb0,2B20, and the ternary compound 15Pb0,3Bz0,,2W0, have been characterized in the ternary system PbO-B20,-W0,.698 The binary phases 2PbO,WO, and P b 0 , W 0 3 have also been shown to occur in the PbO-V,O,-WO, system, together with the phases 3Pb0,V,0s and 2Pb0,V205.699 The reaction between Nb20s, TiOZ, and PbO at 1000 "C produces a non-stoicheiometric phase, Pb2-, (Nb,Ti),O,+, of the pyrochlore type.700 Three phases occur in solid solutions PbZr,-,(Fel,2Nb1/2),03.701 Crystals of [Pb4(OH)4],(C03)(C104)lo,6H20702 and [Pb4(OH)4](C104)4,2H20703 both contain discrete [Pb4(0H),]"+ ions in which the lead atoms occupy the corners of a slightly distorted tetrahedron and the hydroxide groups are located outside the faces of the tetrahedron. Several papers report studies about p -keto-enolato and related derivatives of bivalent tin and lead. These compounds have been prepared by the reaction of either bis(methylcyclopentadienyl)tin, tin dimethoxide, or lead monoxide with the appropriate protic reagent or from tin(rr) chloride and 693

W. Jeitschko and A. W. Sleight, Acta Cryst., 1974, B30, 1088. K. Takahashi, Bull. Chem. Soc. Japan, 1974, 47, 1568. '')< E. G. Fesenko, M . F. Kupriyanov, R. U . Devlikanova, and V. S. Filip'ev, Soviet Phys. Cryst., 1974, 19, 67. hY6 K. Kato, 1. Kawada, and K. Murarnatsu, Acta Cryst., 1974, 830, 1634. 6y7 B. D. Jordan and C. Calvo, Canad. J. Chem., 1974, 52, 2701. 698 V. T. Mal'tsev, A. G. Bergman, P. M. Chobanyan, and V. L. Volkov, Russ. J. Inorg. Chem., 1973, 18, 1764. 699 V. T. Mal'tsev, V. L. Volkov, and T. V. Morgulis. R U S SJ. . Inorg. Chem., 1973, 18, 1786. 700 J. Bachelier, M. Hervieu, and E. Quemeneur, Bull. SOC.chim. France, 1973, 2503. 701 A. Marbeuf, J. Ravez, and G. Demazeau, Rev. Chim. minirule, 1974, 11, 198. '02 S. H. Hong and A. O h , Acta Chem. Scand., 1973, 27, 2309. 703 S. H. Hong and A. O h , Acta Chem. Scand., 1974, 28, 2 3 3 .

"' S. Shirasaki, H. Yarnarnura, K. Murarnatsu, and

300 Inorganic Chemistry of the Main-group Elements the sodium ~ a 1 t . ~ The ~ ) ~ tin(i1) - ~ ~ ~bis(P -keto-enolates) undergo facile oxi&mve-addition reactions, forming dihalogenobis(P -keto-enolato)tin(xv) derivatives on reaction with chlorine or br~mine,'~'and monoalkyltin(1v) halide bis(P -keto-enolates) with alkyl halide^.'^"^''"^^"^ Tin(1r) dimethoxide and bis(acety1acetone) react similarly with diphenyl disulphide to afford X,Sn(SPh), (X = OMe or acac) compounds, which disproportionate to XSn(SPh), and X,SnPh. The reactions with diethyl acetylenedicarboxylate and diethyl azodicarboxylate yield oligomeric addition products of the types [(EtO,C)E-E(CO,Et)Snx,l, (E-E = C=C or N-N), where n has values of six, nine, and higher.70s Lead(r1) bis(hexafluoroacety1acetonate) forms complexes with 1,lO-phenanthroline, 2,2'-bipyridyl, and NNN'N'-tetramethylethylenediamine, and the ionic complex species [Pb(hfac),I2(hfac = hexafluoroacetylacetone) with tmndH' hfac- [tmnd = 1,8-bis(dimethylamino)naphthalene]."" The crystal structure of the mixed-valence tin carboxylate Sn1'Sn'"(0,CC6H,N02-o),0,THF has been determined, and it contains octahedrally co-ordinated tin(rv) atoms and pentagonal-pyramidal tin( 11) atoms. The carboxylate groups bridge the tin(rr) atoms to adjacent tin(rv) atoms, and the oxygen atom not only bridges neighbouring tin(rv) atoms, forming a distannoxane ring, but also co-ordinates to a tin(r1) atom via the axial site of the pentagonal pyramid. The equatorial positions of the pyramid are occupied by oxygen atoms from four bridging carboxylate groups and the molecule of THF of ~olvation.'~~' A detailed study of the Mossbauer parameters of Sn,(edta),2H20 has been carried out over the temperature range 78 d T G 226 K, and the two different metal sites known to be present from the X-ray diffraction study have been identified. Comparison of the data with the complexes MSn(edta) (M = Ca, Ba, Sr, Mg, Co, Mn, or 2Na) have shown that one tin is covalently bound by the chelating edta, whilst the other is present as the gegenion bound by appreciably ionic interactions. The variable-temperature data confirm the absence of phase transitions or structural discontinuities between 78 K and room temperat ~ r e . ~ Lead(1r) ll succinate exhibits a phase transition from tetragonal to cubic at 160 "C, with AH = 0.6 kcal mol-' and AS = 1.4 kcal rn~l-'.''~ The crystal structure of u-penicillaminatolead(I1) shows that the amino-acid functions as a terdentate ligand towards lead(II), forming three strong interactions, with r(Pb-0) = 2.444, r(Sn-N) = 2.444, and r(Pb-S) 2.716 A.In addition, two weaker Pb-S interactions (3.160, 3.480 A) and 711-3

P. F. R. Ewings. D. E. Fenton, and P. G . H a r r i w n , lnorg. Ntccleur ('hrtn. Lrrters. I <>74. 10, 43. 5I'' S. Gopinathan. C . Gopinathan, a n d J. Gupta, Indiun J. Chem.. 197.3. 11, 1067. 71'h C. Gopinathan a n d S. K. Pandit, Indian .I. Chem.. IY7.3, 11, IOW. 7117 I . Wakeshima and I. Kijima. J. Orgunometallic Chem., 1974 7 6 , 37. 711x K. D. Bos, E. J . Bulten, and J . G. Noltes, .J. Orgunometallic C'hem.. 1974. 67, C13. 7114 D. E. Fenton a n d R. Newman. J.C'.S. Dalton, 1974. 655. 710 1'. F. R . Ewings, P. Ci. Harrison, T. J . King, and A. Morris. J.('.S. Chem. Cornm., 1974, 53. "I A. J. Rein. J. L. K. F. De Vries, and R. 14. Herber. J. InorK. Nuclear C'hem., 1974, 36, 8 2 5 . 'I2 K. Nagase and H. Yokobayashi, Chem. Letters, 1974,861.

Elements of Group IV

30 1

one Pb-0 interaction (2.768A) link adjacent lead atoms, resulting in distorted pseudo-pentagonal-pyramidal co-ordination at lead(Ir), with the stereochemically active lone pair occupying an equatorial site (Figure 36).'13 The complexation behaviour of lead(I1) with anions derived from glutamic, ethylenediamine-NN'-diaceti~,~~" ethylenediamine-NN'-dimalonic, -disuccinic, and -diglutaric,' l5 ethylenediaminete tra-ace tic, N-(2-hydroxye thy1)-

Figure 36 The structure of D-penicillaminatolead (11) (Reproduced from J.C.S. Chern. Cornrn., 1974, 366)

ethylenediamine-NN'N'-triacetic, 2,2'-ethylenedioxydi(ethylamine)NNN'N'-te tra-acetic, diethy lenetriaminepenta-acetic, N-( 2 -hydroxye thy1)iminod i a ~ e t i c ,and ~ ~ ~valeric and isovaleric and asparagine, aspartine, cysteine, glutamine, his tidine, phenylalanine, serine, tryp t ~ p h a nl 8, ~ pyridoxine,"' and dopamine, adrenaline, noradrenaline, and tyramine720 have been studied. Complexation between lead(I1) formate, acetate, propionate, butyrate, valerate, and caproate with piperidine, and also between lead(I1) perchlorate and substituted thioureas, has been Hydrated sodium hypophosphite in methanol rapidly reduces germanium(1v) chloride to Ge"(HP0,). The addition of a large cation such as NMe,H', Rb', or Cs' to the reaction mixture results in the formation of the complex species M'[Ge(HPO3)C1]-. Whereas no significant reaction occurs between Ge(HP0,) and HBr, HCI, HF, H,SO,, or HN03, concentrated HI 713

H. C. Freeman, G. N . Stevens, and I. F. Taylor, J.C.S. Chem. Comm., 1974, 366. M. Kodama, Bull. Chem. Soc. Japan, 1974, 47, 1547. '" I. P. Gorelov, A. P. Samsonov, and M. K. Kolosova, Russ.J. Inorg. Chem., 1973, 18,934. 7 1 h M. Kodama, K. Namekawa, and T. Horiuchi, Bull. Chem. Soc. Japan, 1974, 47, 2011. 'I4

717 'IH

719

72 I 722

K. K. Choudhary, D. S. Jain, and J. N. G a u r , Indian J. Chem., 1974, 12, 655. A. M. Corrie, M. L. D. Touche, and D. R. Williams, J.C.S. Dalton, 1973, 2561. D. N . Chaturvedi and C. M. Gupta, J . Inorg. Nuclear Chem., 1974, 36, 2155. B. Grgas-KuZnar, V. Simeon, and 0. A. Weber, J. Inorg. Nuclear Chem., 1974, 36, 2151. R. I. Kharitonova and S. S. Sydykova, Russ. J. Inorg. Chem., 1973, 47, 504. V. A. Fedorov, A. V. Fedorova, G. G. Nifant'eva, L. G. Soboleva, and L. I. Gruber, Russ.J. Inorg. Chem., 1973, 18, 1778.

Inorganic Chemistry of the Main -group Elements

302

-1

3 3

I

Figure 37 The co-ordination of the lead atom in cerussite, PbCO, (Reproduced by permission from Z . Krist., 1974, 139, 215) converts the compound into Ge12.727Tin(1i) monofluorophosphate has a structure consisting of sheets of PO,F anions with tin(ri) ions lying midway between the anion layers. Each tin(I1) ion has six oxygen and two fluorine neighbours. Three of the oxygens are a t short distances (mean 2.15 A), the other three being a t an average distance of 3.13 A from the tin. T h e two fluorine atoms are a t an average distance of 3.49A from the tin.72JIn cerussite, PbC03, the lead(I1) atoms are in nine-fold co-ordination, with one oxygen at 2.62 A, and two each at 2.66, 2.68, 2.7 1 , and 2.77 A (Figure 37).725T h e reaction of tin([]) chloride and methanesulphonic acid produces 723 724 725

P. S. PobkoLim and C . P. Ciucngerich. I t i o r g . C'hetti.. 1974. 13, 241 A . F. Berndt, Acta Cryst.. I Y 7 4 . B30, 529, K . Sahl, Z . Krist.. 1974. 139, 215.

Elements of Group IV

303

tin(rr) methanesulphonate, which forms adducts with pyridine and butylamine. Freezing-point studies in the Cs0,SMe-Sn(O,SMe), system M’ and M3’ species indicate the presence of the phase CS,S~(O,SM~),.’*~ (M =Sn or Pb) have been detected in the e.s.r. spectra of 6oCoy-irradiated tin and lead The e.s.r. spectra of irradiated lead(I1) nitrate provide evidence for electron transfer to and from lead(r1) Sulphur Derivatives. The crystal structures of a number of lead sulphide minerals have been determined. PbGeS, consists of GeS, tetrahedra linked to form infinite [(GeS,),]’”- chains, with two tetrahedra’per identity period. The co-ordination sphere of the lead(I1) atoms is occupied by five sulphur atoms at distances of between 2.736 and 3.016A in a distorted squarepyramidal arrangement, with the lone pair occupying the sixth octahedral The structure of freieslebenite, PbAgSbS,, is a superstructure of a PbS-type substructure. Lead is co-ordinated by six sulphur atoms in a distorted octahedral arrangement, with Pb-S distances ranging from 2.806 to 3.167A.732Cosalite, Pb2Bi,Ss, has two lead atoms in the unit cell that have distorted octahedral co-ordination and two which are eight-coordinated with sulphur atoms at the apices of a trigonal prism and two additional sulphur atoms. The Pb-S distances fall in the range 2.723.47 A.733 In plagionite, PbSSb,Sl7,two lead atoms have six- and seven-fold co-ordination, respectively, in octahedral-like configurations. A third lead atom is surrounded by eight sulphur atoms in an arrangement which may be described as either a square antiprism or as a trigonal prism with neighbours along two face The structure of jordanite is a deformed PbStype, and is made up of alternate layers of metal sites (Pb+As) and sulphur atoms. Some of the metal sites have statistical nature; thus one site is occupied by 0.5Pb + 0.5As and another is occupied by 0.88Pb, giving a Lead sulphide forms with GeS2 in the unit-cell content of Pb27.8A~12.0S45.8.735 presence of GeS stable glasses in a large range of composition. Melts In the containing an excess of sulphur yield inhomogeneous glasses of the same GeS2-GeS system it is also possible to substitute SnS for GeS over a wide range. The Mossbauer spectra of the glasses are very similar to the compound SnGeS,, which crystallizes from the glasses on annealing.737The reaction of trimethylaluminium with PbS gives Me,Pb,

’” R. C. Pal, V.

P. Kapila, and S. K. Sharma, Indian J. Chern., 1974, 12, 651. H. C. Roberts and R. S. Eachus, J . Chem. Phys., 1973, 59, 5251. R. J. Booth, H. C. Starkie, M. C. R. Symonds, and R. S. Eachus, J.C.S. Dalton, 1973, 2233 ’”’ H. C . Starkie and M. C. R. Starkie, J.C.S. Dalton, 1974, 731. 730 M. C. R. Symonds, D. X. West, and J. G. Wilkinson, J.C.S. Dalton, 1974, 2247. ’” M. Ribes, J . Olivier-Fourcade, E. Philippot, and M. Maurin, Acta Cryst., 1974, B30, 1391. 7 3 2 T. lto and W. Nowacki, Z . Krist., 1974, 139, 8 5 . ’’’ T. Srikrishnan and W. Nowacki, Z. Krist., 1974, 140, 114. 734 S. A. Cho and B. J. Wuensch, Z . Krist., 1974, 139, 351. 73s T. Ito and W. Nowacki, Z. Krist., 1974, 139, 161. 7’6 A. Feltz and B. Voigt, Z . anorg. Chem., 1974, 403, 61. 737 A. Feltz, E. Schlenzig, and D. Arnold, Z. anorg. Chem., 1974, 403, 243. 727

’’’

304

Inorganic Chemistry of the Main-group Elements

Figure 38 ( a ) The molecular structure of, a n d (b) the arrangement of, the hetero -atoms about the lead in C,,H,,N,O,,Pb(SCN), (Reproduced by permission from Inorg. Chem., 1974, 13, 2094) lead, and bis(dimethyla1uminium) ~ulphide.'~'Lead thiolates Pb(SR), react with chloroboranes to afford thioboranes of the types Ph,B(SR)3-, (n = 0, 1, or 2).'" The complexation equilibria between Pb2+and ( f)-2,3-dimercaptosuccinic and (+)-2,4-dimercaptoglutaric acids have been studied.'""

'-"M. Boleslawski, S. Pasynkicwicz, and A. Kinicki, J. Organometallic Chem.. 1974, 73, 193. ''"R. H . Ci-agg, J . P. N. Husband, and A. F. Weston, J. 7norg. Nuclear Chem.. 1973, 35,3685. 740

L,. G. Egorova and V. L. Nirenburg, .1. Gen. CCtem. (U.S.S.R.),1973. 43, 1533.

Elements of Group IV

305

Nitrogen Derivatives. The preparation of simple amino-derivatives of bivalent germanium, tin, and lead has been reported. The reactions of SnCl,, PbCl,, or GeCl,,dioxan with the lithium salt LiNBu'(SiMe,) or LiN(SiMe,), in ether at 0 "C yield the compounds M[NBu'(SiMe,)], and M[N(SiMe,),],, respectively, as stable, diamagnetic, coloured, volatile, and low-melting materials which are soluble in hydrocarbon solvents. Several reactions of the tin(I1) derivatives have been described. In particular, the tin compound undergoes oxidative addition with (C5H,)(C0),FeMe [to give (C,H,)(CO),Fe{Sn(NR,),Me}], metathesis with acetic acid, ethanol, HCl, or cyclopentadiene [to afford Sn(02CMe),, Sn(OEt),, SnCl,, or Sn(C5H,),], redistribution with SnC1, or Sn(C5H,), [to give (XSnNR,), (X = C1 or C,H,)] and with LiCH(SiMe,), {to give Sn[CH(SiMe3),l2 and LiNR,}, and insertion with phenyl isocyanate [to give Sn(NPhCONR2),].'"' The compounds were deduced to be monomeric both in solution (cryoscopy) and in the vapour (mass s p e c t r ~ m e t r y ) , ~but ~ ' Sn[N(SiMe,),], has also been synthesized by Z ~ c k e r m a n who. , ~ ~ ~observes dimeric character also both in solution (osmometry) and in the vapour (mass spectrometry). Obviously, this discrepancy needs to be resolved. In addition, Zuckerman has also prepared several heterocyclic tin(I1)-nitrogen derivauves, some as THF s01vates.'~~ Irradiation of the germanium and tin derivatives M[N(SiMe,),], yields the very long-lived metal-centred radicals *M[N(SiMe,)2]3.743 The crystal structure of the lead cryptate C,,H3,N,O6,Pb(SCN), consists of discrete molecules (Figure 38a) in which the lead atom occupies a central position in the cavity of the macrobicyclic ligand. Each lead atom is surrounded by one sulphur [Pb-S = 3.121(3) A], three nitrogen [Pb-N= 2.642(10), 2.858(9), 2.909(9) A], and six oxygen atoms [Pb-0 = 2.729(7)-2.980(8) A], in an arrangement which approximates to a trigonal-capped irregular hexagonal pyramid (Figure 38b).'44 The effect of iron impurities on the thermal decomposition of lead azide has been ~tudied.'"~ The vibrational spectra of pure lead azide as well as of pure and doped samples that have been exposed to U.V.radiation have been examined,746-748 as have the i.r. spectra of the complexes NMe:[Sn(,NCO),]-, M(NCO),,2phen, and Pb(NCO),,bipy. In all the latter complexes, the NCO group is bonded to the metal uia the nitrogen atom.'"' Interactions of Bivalent Germanium and Tin Compounds, with Transitionmetal Derivatives. Several investigators have studied the ligand qualities of 74'

D. H . Harris and M. F. Lappert, J.C.S. Chern. Comrn., 1974, 8YS.

742

C. D. Schaeffer and J. J. Zuckerman, J. Amer. Chern. SOC.,1974, 96, 7160.

743

744

745

746 747

74x 749

J. D. Cotton, C . S. Cundy, D. H. Harris, A. Hudson, M. F. Lappert, and P. W. Lcdnor, J.C.S. Chem. Cornm., 1974, 651. B. Metz and R. Weiss, Inorg. Chern., 1974, 13, 2094. R. W. Hutchinson and F. P. Stein, J . Phys. Chem., 1974, 78, 478. K. Dehnicke, Z . anorg. Chem., 1974, 409, 311. S. P. Varma, F. Williams, and K. D. Moller, J. Chem. Phys., 1974, 60, 4950. S. P. Varma and F. Williams, J . Chem. Phys., 1974, 60, 4955. A. Y. Tsivadze, G. V. Tsintsadze, and T. L. Makhatadze, J . Gen. Chem. (U.S.S.R.),1974,44, 157.

306

Inorganic Chemistry of the Main- group Elements bivalent germanium and tin species. The photochemical reaction between 3benzothiazole-dichlorogermylene and chromium, molybdenum, and tungsten hexacarbonyls yields the complexes C,H,NS,GeCl,,M(CO), (M = Cr, Mo, or W).'" Group VI metal pentacarbonyl complexes of tin(11) halides and germanium dichloride have been obtained similarly from the hexacarbony1 and SnX, ( X = C1, Br, or I) or CsGeC1,. The resuiting M'X,,M(CO), (M = Sn, X = C1, Br, or I; M = Ge, X = C1) react further with NMe,'X in THF to form the complex anions [M(CO)sM'XJ.7s1 Mixed complex anions [M(CO),SnBr,_, C1,]- are formed when the metal hexacarbonyls are allowed to react with the mixed [SnBr,-,Cl,]- anions. The reactions of dibenzenechromium with these mixed halogenostannite anions lead to the formation of [Cr(SnBr,-, CI,),]" complex anions.752,753 The [SnCI,]- anion reacts with (C,&)M(CO), complexes (M = Cr or Mo) to form [M(CO),(SnC1,),]3- complex anions, whilst only C O displacement occurs in the reaction with (C,H,)V(CO), to yield the [(C,HS)V(CO),SnCI,),~-anion.753The reactions of [(Me,Si),CH],Sn with several transition-metal derivatives have been examined. With Cr(C0)6, the complex [(Me,Si),CH],Sn-+Cr(CO), is formed, the structure of which is shown in Figure 39, which confirms the

Figure 39 The structure of [(Me,Si),CH],SnCr(CO), (Reproduced from J.C.S. Chem. Cornm., 1974, 893)

''"P. Jutzi

and H. J . Hoffman. Chum. Ber., 1973, 107, 3616. H. Behrens. and E. Lindner, 2. unorg. Chem.. 1973, 401, 7 3 3 . '" T. Kruck, F. J . Becker, H. Breuer, K . Ehlert, and W. Rother. Z . unorg. Clwm.. 1474, 405, 95. 7T' '1'. Kruck and H. Breuer. Chem. Ru.. 1974. 107, 7 h 3 . 711

I). Uhlig,

Elements of Group IV 307 presence of a direct Sn-Cr bond [2.562(5)A]. The two carbon atoms and the chromium atom are coplanar with the tin. Other reactions are summarized in Scheme 4.754 Bis(methylcyclopentadieny1)tin reacts with [(Ph3P)dR,Sn)RhC11 purple, m.p. 184-187 "C

trans -[(R,S n),Mo(CO),]

"\\

/ orange, m.p. 204-205

"C

R,Sn

Fe -

[(Et,P)PtCI(SnR,)(SnR,Cl j]

brown, m.p. 167-170 "C

[Cp(CO),Mo-SnR,H] yellow, m.p. 128-130 "C

[Cp(CO),Mo-SnR,Me] brown, m.p. 103-105 "C

Reagents: i, [(Ph3P)3RhCI]; ii, (nbd)Mo(CO),; iii, [(Et3P)PtCl2I2; iv, [CpFe(CO),],; [Cp(CO),MoH]; vi, [Cp(CO),MoMe].

v,

Scheme 4

CO,(CO)~ slowly to form Sn[Co(CO),],. Tin(ri) halides, cyclopentadienyls, and P-keto-enolates react readily with Fe2(CO), to afford the dimeric [X,SnFe(CO),], derivatives, which undergo base-induced Sn-Fe bond fission to yield base-stabilized monomeric species.7s5Tin(I1) chloride inserts into the Fe-C bond of (C,H,)Fe(CO),R (R = CH,CH=CH,, CH,CMe=CH,, CH,CH=CHMe, or CH,CH=CMe,) in THF to yield the insertion product (C,H,)Fe(CO),SnCl,R. When treated with either excess SnC1, in THF or SnCl, in methanol, (C,H,)Fe(CO),CH,CMe=CH2 yields (C,H,)Fe(CO),SnCl, as the major product. This compound is the only product when R = CH=C=CH,, CH2C-CMe, or CH,CMe:. Tin(I1) iodide reacts with (C,H,)Fe(CO),CH,CH=CH, in benzene to form (C,H,)Fe(CO),I. Lead(i1) chloride does not react.7s6Tin(I1) chloride also inserts into (C,H,)Fe(CO),Me to give MeCl,SnFe(CO),(C,H,) together with traces of Cl,SnFe(CO),(C,H,), but with EtFe(CO),(C,H,) a mixture of C1,SnFe(CO),(C,H,) and Cl,Sn[Fe(CO),(C,H,)], is obtained. Reactions involving tin( 11) bromide gave mixtures of halogeno-metal carbonyls and halogenotinSix types of compound, (Bu,P)Co(CO),SnX,, [(Bu,P)Cometal carbonyl~.~'~ (CO),],SnX,, [(BuJ')Co(CO)3],SnX, [(BuJ')Co(CO)3],SnH, [(Bu,P)Co(CO),],Sn, and (BU,P),CO(CO)~X, have been isolated from the reactions of 754

755 756 757

J . D. Cotton, P. J. Davidson, D . E. Goldberg, M. F. Lappert, and K. M. Thomas, J.C.S. Chem. Comm., 1974, 893. A. B. Cornwell, P. G. Harrison, and J. A. Richards, J . Organometallic Chem., 1974, 76, C26. C. V. Magatti and W. P. Giering, J. Organometallic Chem., 1974, 73, 85. B. J. Cole, J. D. Cotton, and D. McWilliam, J. Organometallic Chem., 1974, 64, 223.

Inorganic Chemistry of the Main-group Elements 308 tin(r1) halides SnX2 (X = F, C1, Br, or I) and [ ( B u ~ P ) C O ( C O depending )~]~ on the reaction conditions, the mole ratio of reactants, and X. The reactions are thought to proceed either by direct insertion of SnX, into the Co-Co bond, or by the scission of this bond to give (Bu,P)Co(CO),SnX,, which may react further with [(Bu,P)CO(CO),],.'~~The hydride [(Bu,P)Co(CO),],SnH may also be obtained from tin(rr) sulphate and Na[Co(CO),(PBu,)] in aqueous diglyme, and is air-stable.'" A similar tin hydride has also been obtained from the reaction o f (C5H&3n with HMn(CO),. The crystal structure of the product, HSn[Mn(CO),],Sn[Mn(CO)5]zH, is shown in Figure 40, and it contains tin atoms in a strongly distorted tetrahedral envir~nrnent.'~" Red crystalline ReSn[CS(NH,),],CI,,H20 has been obtained by the reaction of HReO, in 3M-hydrochloric acid with thiourea and a

Figure 40 The structure of HSn[Mn(CO),],Sn[Mn(C0),1,H (Reproduced by permission from J . Organornetallic Chem., 1974,71,C 5 2 )

''' P. 75y

''('

Hackett and A. R. Manning, J.C.S. Dalton, 1974, 2257.

P. Hackett and A. R. Manning, J. Organornetallic Chem., 1974, 66, C17. K. D. Bos, E. J . Bulten, J . G. Noltes, and A. L. Spek, J. Organornetallic Chem., 1974. 71, CS2.

Elements of Group IV 309 solution of SnCl, in l0M-hydrochloric acid. Unit-cell data were obtained, but the structure could not be refined.761

3 Intermetallic Phases Binary Systems.-The temperature dependence of the solubility of Ge and of Sn in liquid sodium has been determined, together with the hypereutectic liquidus of the sodium-rich section of the Na-Sn phase diagram.762The compounds precipitating from these dilute solutions have been shown to be NaGe and Na,5Sn,. Solubility of the Group IV elements in liquid sodium increases in the order C < G e < S n < P b as the metallic character of the solute becomes more pronounced.76zThe crystal structures of Ca,Si, and Ca,Ge,, which are newly prepared compounds, have been determined;763 they crystallize in the tetragonal Cr,B, structure type and their unit-cell dimensions are compared with those of the isostructural interme tallics Sr,Si, and Ba,Si, in Table 21. The thermal stability of CaSi and several of its Under vacuum, thermal reactions with 0, and N, have been decomposition [reaction (75)] yields CaSi,. Reaction with 0, [reaction (76)] 2CaSi + CaSi, + Ca 4CaSi+ 3 0 2+ a’-Ca,SiO,

(75)

+ 2 C a 0 + 3Si

(76)

at high temperatures gives a’-Ca,SiO,, CaO, and Si. The oxidation is a multi-stage reaction and it has been possible to isolate the products of the initial stage (77) between 550 and 600°C. These products then react with 2CaSi + +O,4 CaSi, + CaO

(77)

0, at temperatures above 700°C to form y-Ca,SiO,, which transforms to a’-Ca,SiO, at 1000°C. With N,, the reaction products again depend on temperature; below 900 “C, Ca,SiN, is obtained by reaction (78), whereas between 900 and 1200°C pure CaSiN, is formed [reaction (79)].

4CaSi + 2N,

+ Ca,SiN,

CaSi + N, + CaSiN,

+ 3Si

(78) (79)

A new modification of SrSi and the new compound SrGeo.76 have been prepared and their structures determined .765 The two intermetallics are isostructural, crystallizing with orthorhombic symmetry; their unit-cell parameters are included in Table 21. A fascinating facet of these structures 7hI

762 763 7h4

765

V. G. Kuznetsov, G. N. Novitskaya, P. A. Koz’min, and L. V. Borisova, Russ. J. Inorg. Chem., 1973, 18, 214. P. Hubberstey and R. J. Pulharn, J.C.S. Dalton, 1974, 1541. B. Eisenmann and H. Schafer, Z . Naturforsch., 1974, 29b, 460. A. Gourves and J. Lang, Compt. rend., 1974, 278, C, 617. B. Eisenmann, H. Schafer, and K. Turban, Z . Naturforsch., 1974, 29b, 464.

3 10

Inorganic Chemistry of the Main-group Elements Table 21 Unit-cell parametersIA of Ca,Si,, CasGe3, Sr,Si,, Ba,Si,, SrSi, and SrGe0.7h Compound a b C

Ca& 7.64(2)

Ca,Ge, 7.74(2)

Sr,Si, 8.05(1)

Bassi, 8.436(6)

-

-

-

-

14.62(2)

14.66(2)

15.68(1)

16.53(1)

SrSi 12.98 4.89 18.03

SrGe,, 7 h 13.38 4.84 18.52

is the geometrical arrangement of the Group IV atoms, as shown in (41) and (42); they form a planar hexagon of Si (or Ge) atoms substituted in the

1, 2, 4,5 positions by four additional Si (or Ge) atoms. In SrGeo76,there are defects in the 1 , 2, 4, 5 positions, whereas in SrSi no indications of such defects could be found. The geometrical parameters of these units are summarized in the diagrams.'"' A group of Russian workers have determined the V-Si'"" and W-Si7"' phase diagrams. Four intermetallic compounds were observed in the V-Si system, V,Si (m.pt. 1935 "C), V,Si, (m.pt. 201 0 "C), V,Si, (peritectic, d. 1670"C), and VSi, (m.pt. 1680°C), and two in the W-Si system, W,Si3 (m.pt. 2095°C) and WSi, (m.pt. 2020°C). Tungsten deposited on PtSi, which in turn is deposited on silicon, will react to form WSi, at temperatures in excess of 750 0C;7"8silicon is the diffusing species and PtSi provides an unpassivated interface between the reactants. Various transition-metal silicides are also found on annealing (800-900 "C) other refractory metals (M=Ti, V, Cr, Ta, Mo, Ni, or NiCr) on PtSi on silicon. The stability of WSi, is evidenced by the fact that on annealing systems of the type W-MPtSi-Si, WSi, is formed in all cases except that where M = C r , when ca. 50% of the tungsten is transformed at 900"C.7"8The films formed when silicon is deposited on Mo from molten fluoride electrolytic baths have been identified as MoSi,;'"' this intermetallic imparts to Mo a remarkable resistance to high-temperature oxidation. The electrical conductivity of single crystals of Mn2?SL7has been determined parallel to and perpendicular to the c -axis;'" anisotropic behaviour was observed, particularly at low temperatures. Mn,,Si,, was found to be a

''''

Yu. A . Kocherzhinskii, 0. G. Kulik, and E. A. Shishkin. Doklady C'hern., 1973, 209, 333. Yu. A. Kocherzhinskii. 0. G. Kulik, E. A. Shishkin, and L. M. Yupko, Doklady C'hern.. 1974, 212, 782. '" A. K. Sinha. M. H. Read, and T. E. Smith, J. Electrochem. SOC.,1973. 120, 177.5. '" N. Petrescu, M. Petrescu, M. Britchi, and L. Pavel, Rev. Roumaine Chim., 1973, 18, 18.53. '"' G. Zwilling and H. Nowotny, Monatsh., 1974, 105, 666.

'*'

Elements of Group IV 311 p-type semiconductor, in agreement with literature data on similar defect silicides. The crystal structure of Fe6Ge, has been shown to be monoclinic, with unit-cell parameters a = 9.965(5), b = 7.826(5), c = 7.801(5) A, p = 109"40'*10';77' it has been coMpared to that of the isostructural Fe,Ga, and to those of the germanides and gallides of the other Group YIII transition metals. An Auger examination of a series of solid and liquid Pb-In solutions has shown that the relative intensity ratio of the Pb and In peaks is a sensitive indicator of changes in surface composition with respect to temperature and bulk The surface layers were richer in Pb than the bulk; this excess Pb concentration was decreased by the presence of oxygen but increased by carbon. Four investigations of the thermodynamic properties of systems contain~ ~ - ~ ~ deviations ~ ing Group IV elements have been ~ n d e r t a k e n . ~Positive from ideality were exhibited by Ge-Pb solutions (0.13 d xGed 0.92) at The thermodynamic properties temperatures between 900 and 1050 0C.773 of liquid Ge-Cu (1525 "C) and Ge-Au (1400 "C) have been determined using mass-spectrometric both systems exhibited negative deviations from ideal behaviour. In contrast, ys, in Si-Ag solutions (0.015 x S i s0.29) in the temperature range 1100-1325 "C was slightly greater than unity at all concentration^^^^ The enthalpy of formation of the intermetallic compound GeSe [AH*(GeSe) = - 10.1 2.0 kcal mol-'] and the absolute entropy [AS* (GeSe) = 16.9 f 2 cal K-' mol-'1 have been calculated from the results of a Knudsen effusion study of the sublimation of polycrystalline GeSe.776

*

Ternary Systems.-Phase equilibria in the Ge-Sn-Se,'" Sn-Na-Bi,77s and Sn-Cd-Hg779 systems have been determined. In the Ge-Sn-Se system, equilibria in the triangle GeSe,-SnSe2-SnSe have been described;"' the GeSe,-SnSe, and GeSe,-SnSe systems are quasi-binary, with eutectics at 569 "C and 50 rnol.O/o GeSe, and 580°C and 45.1 mol.% GeSe,, respectively. The ternary eutectic (556 "C) has the molecular composition GeSe2,SnSe,,0.75SnSe."' The effect of Na, which is employed as coolant in fast breeder reactors, on the freezing point of the Bi-Sn eutectic (139 "C), a fusible seal in these reactors, is to cause a decrease (to 125 "C) at concentrations up to 16 atom O/O Na.77RInteractions between G e and Sn and between 77 1

772

173

774

775 776 777 77x

779

B. Malarnan, M . J. Phillippe, B. Roques, A . Courtois, and J. Protas, Acta Cryst., 1974, B30, 2081. S. Berglund and G. A. Sornorjai, J. Chem. Phys., 1973, 59, 5.537. G. I. Batalin, V. A. Stukalo, E. A. Beloborodova, and A. I. Nikiforova, Russ.J. Phys. Chem., 1973, 47, 914. J. P. Hager, S. M. Howard, and J. H. Jones, Metallurg. Trans., 1973, 4, 2383. H . Sakao and J. F. Elliott, Metallurg. Trans., 1974, 5, 2063. H. Wiedemeier and E. A . Irene, Z . anorg. Chem., 1974, 404, 299. L. Bald6 and P. Khodadad, Compt. rend., 1974, 278, C, 243. T. F. Kassner and C. A. Youngdahl, Metallurg. Trans., 1973, 4, 2663. N. M. Atamanova and M. V. Nosek, Russ. J . Phys. Chem., 1973, 47, 1647.

Inorganic Chemistry of the Main -group Elements

3 12

Sn and Pb dissolved in liquid Na have been investigated using resistivity techniques.780A t the concentrations studied ( <2 atom O/O total solute), no interactions were observed. The ternary phase diagram of the Sn-Cd-Hg system has been determined at constant Sn concentrations (20, 40, and 70 atom O/O Sn).”’ Seven papers describing the results of crystal studies of ternary intermetallic phases have been p ~ b l i s h e d ; ~the ~ ~relevant - ~ ~ ~ unit-cell parameters of these compounds are collected in Table 22. CdGeAs, has been shown to be stoicheiometric and to crystallize in the chalcopyrite ~ t r u c t u r e . ’The ~~ new compounds BaMg2X, (X = Si, G e , Sn, o r Pb) have been prepared and their structures determined;78’ BaMg,Si, and BaMg,Ge, crystallize in the ThCr,Si,-type structure, whereas BaMg,Sn, and BaMg,Pb, show new atomic arrangements, which are layer variants of the above type. Two modifications, monoclinic and hexagonal, have been found for Li5Fe7Ge8.783 The intermetallic phase Li,CeGe has been prepared by direct reaction of the elements and has either a modified Li,Bi o r Na,As The crystal structure of Ce,Ni,Si, is of a new with respect to the composition and arrangement of the smaller atoms, it resembles closely the Ho,Co, (Ho12C09)structure, and represents a completion of its superlattice structure. The isostructural compounds M,Ni,Si, (M = La, Pr, o r Nd) have also been The distribution of the Ni and Si atoms in Ce,,Ni,Si,, is partially disordered and corresponds to the formula Ce,,NiX,Si,,, where X = Ni,,,Si0.,.786The structure of Ce,,Ni,Si,, belongs to the same homogeneous series as Ce,NiSi and Ce,Ni,Si,.785 In a of the Nb-Co-Si system Table 22 Unit-cell parameters of ternary intermetallic phases Phase CdGe As, BaMg,Si, BaMg,Ge, BaMg,Sn, BaMg2Pb, Li,Fe,Ge, Li,Fe,Ge, Li,CeGe Ce, Ni, Si, La,Ni,S i, Pr,Ni,Si, Nd,Ni,Si, Ce,,Ni,Si ,3 Nb,.Co,,Si,, 7x‘1

’” 7x2 7x7

7xJ

”’

’“ 7x7

Symmetry tetragonal tetragonal tetragonal tetragonal tetragonal monoclinic hexagonal orthorhombic hexagonal hexagonal hexagonal hexagonal he xago nal hexagonal

alA 5.9432(1) 4.65(2) 4.67(2) 4.89(2) 5.00(2) 8.74 8.74 18.73 12.112(5) 12.200 12.005 11.905 20.27 17.18

CIA P 11.2163(3) 1 1.O9(2) 11.33(2) 24.20(4) 12.1 l ( 2 ) 14.84 101”25’ 8.03 4.5 1 4.323(2) 4.350 4.273 4.275 4.306 7.92 -

Ref. 78 1 782 782 782 782 783 783 784 78 5 785 785 785 786 787

P. Hubbcrstey and R. J. Pulharn, J.C.S. Faraday 1, 1974, 70, 1631. S. C. Abrahams and J. L. Rernstein, J. Chem. Phys., 1974, 61, 1140. H. Eiscnmann and H. Schafer, Z . anorg. Chem., 1974, 403, 163. H.-U. Schuster and E. Welk, Z . Naturforsch., 1974, 29b, 698. H.-U. Schuster and A. Czybulka, Z. Naturforsch., 1974, 29b, 607. 0. I. Bodak, E. I. Gladyshevskii, and 0. 1. Kharchenko, Soviet Phys. Cryst., 1974, 19, 45. M. G . Mys’kiu, 0. I. Bodak, and E. I . Gladyshevskii, Soviet Phys. Cryst., 1974, 18, 450. J . Steinmetz, J.-M. Albrecht, and B. Malaman, Compt. rend., 1074. 278, C, 773.

Elements of Group IV 313 at 12OO0C, a new ternary silicide, Nb,,Co,,Si,,, has been observed in equilibrium with the phases CoSi, CozSi, and a Co-rich Nb-poor NbCoSi (Nbo.85Col.15Si).Electrical measurements, galvanomagnetics, and e.p.r. spectra show that substitution of Sn by Cr in Sn,-,Cr,Te alloys is very has been limited.788Finally, a novel ternary a-phase Cr,39-0.57M0,.47-,.29Si0.14 detected in the Cr-Mo-Si system at 1500 0C;789it undergoes eutectoid decomposition at ca. 1200 "C into (Cr,Mo) and (Cr,Mo),Si. 7XR 789

A. Katty and 0. Gorochov, Cornpt. rend., 1974, 279, C , 137. E. Rudy and H. Nowotny, Monatsh., 1974, 105, 156.

5 Elements of Group V BY A.

MORRIS AND D. 6. SOWERBY

1 Nitrogen Elementary Nitrogen.-The controversy surrounding the exact structure of (Y -N2 continues to receive attention. Electron-diffraction patterns obtained from annealed single crystals of a - N , have been interpreted in terms of the centrosymmetric space group Pa 3 rather than P2,3. The possibility was discussed that twinning could explain a previous X-ray observation of isolated reflections which were not consistent with the Pa3 structure.’ O n the other hand, Lipscomb2 has noted that all the reflections in an X-ray analysis show a statistically significant preference for P2,3. However, he regards the attainment of more accurate data to be desirable. The measuring procedure and corrections for the high-precision massspectrometric analysis of isotopic abundance ratios of NZ have been de~ c r i b e d Energy .~ levels and a potential-energy curve have been calculated for N2, using an independent-particle A simple symmetry consideration has been used to explain why Koopmans’ theorem fails to explain the assignment of the ionization potentials of N2.5High-resolution photoelectron spectra have been recorded €or N, with a fully calibrated energy analyser at both the 736 and 744 A Ne (I) lines.‘ The pure rotation and rotation-vibration Raman spectra of I4N2,14N1’N, and I5N, have been analysed to give the internuclear distances (re) for each species. The distances are identical, within experimental accuracy, as required by the Born-Oppenheimer approximation. The mean value for re is 1.097 701 f0.000 004 A.’ The Raman spectrum of y-N, at 3 temperatures has been reported8 and the Raman spectra of a - N 2 and y-N, under high pressure at 4 . 2 K have been measured, and the phase change has been identified.’ J. A. Venables and C. A. English, Acta Cryst., 1974, B30, 929. W. N. Lipscomb, J. Chem. Phys., 1974, 60,5138. W. G. Mook and P. M. Grootes, Internat. J. Mass Spectrometry Ion Phys., 1973, 12, 273. K. J. Miller and A. E. S. Green, J. Chem. Phys., 1974, 60, 2617. L. S. Cederbaum, Chem. Phys. Letters, 1974, 25, 562. J. L. Gardener and J. A. R. Samson, Chem. Phys. Letters, 1974, 26, 240. ’ J. Bendtsen, J. Raman Spectroscopy, 1974, 2, 133. ’ F. D. Medina and W. B. Daniels, J. Chem. Phys., 1973, 59, 6175. M. M. Thiery, D. Fabre, M. Jean-Louis, and H. Vu, J. Chem. Phys., 1973, 59, 4559.

3 14

Elements of Group V

315 Sellmann has produced a thoughtful review of dinitrogen transition-metal complexes.'o Co-condensation of rhodium atoms with N, and N2-Ar mixtures at 10 K gives Rh(N,), (n = 1-4) species which have been identified by i.r. In solid N2, Rh(N,), has a distorted tetrahedral structure; a site symmetry of D2, gave a satisfactory fit to all the observed spectral lines. However, in an argon matrix, the structure appears to approach a regular tetrahedron more closely." Using non-empirical calculations, the details of the bonding in Ni(CO), and Ni(N,), have been investigated, and a remarkably close resemblance has been found." The main difference was that the n* orbital in CO is lower in energy and geometrically more favourable for back donation. The difference in metal-ligand bond strength was estimated to be 18 kcal mol;'. Treatment of (CsMe5)2TiNzwith HCl yields (C5Mes)2TiCl,, N,, H2, and N2H4." It has been shown that the reduction of N, to hydrazine in the MgN,-V"-V"'-Mg"-KCl-KOH-H,Osystems does not take place in the absence of Zn". The dependence of the yield of hydrazine on the Zn" concentration shows an extremal value, and the position of the maximum depends on the concentration of metallic magne~iurn.'~ Schrauzer1' has continued his study of nitrogenase model systems composed of molybdate and thiol ligands to include a study of ferredoxin-type complexes as electron-transfer catalysts. van Tamelen and co-workers have discovered a novel biogenetic-type reaction in which a new ferredoxin cluster (1) and a reducing agent (e.g. sodium fluoranthrene) produce ammonia from the molybdenum dinitrogen complex (2). This abiological reaction, although proceeding in small yield, carries distinct implications for the chemical nature of the biological N,-fixation process.16

I

/s

Et

E;

Ph

(1) 10 11

12 13 14

15

16

(2)

D. Sellmann, Angew. Chem. Internat. Edn., 1974, 13, 639. G. A. Ozin and A. Vander Voet, Canad.J . Chem., 1973,51, 3332. H. B. Jansen and P. Ros, Theor. Chim. Acta, 1974, 34, 85. J. E. Bercaw, J . Amer. Chem. SOC., 1974, 96, 5087. D. V. Sokol'skii, Ya. A. Dorfman, Yu. M. Shindler, and V. S. Emel'yanova, Russ. J. Inorg. Chem., 1973, 18, 1667. G. N. Schrauzer, G. W. Kiefer, K. Tano, and P. A. Doemeny, J. Amer. Chem. SOC., 1974,96, 641. E. E. van Tamelen, J. A. Gladysz, and C. R. Briilet, J. Amer. Chem. Soc., 1974, 96, 3020.

316 Inorganic Chemistry of the Main -group Elements A new theory of active nitrogen has been proposed.” Several reactions of active nitrogen have been investigated. With simple alcohols the stable product was HCN in all cases1* and with C’C1, .several products were formed, including cyanogen chloride, cyanogen, carbon tetrachloride, trichloroacetonitrile, and ch10rine.l~E.s.r. spectroscopy has been used to characterize low-temperature (77 K) intermediates produced from active nitrogen and many simple molecules, e.g. H 2 0 , NH3, and small hydrocarbons and their amine and chlorine derivatives.’”

Bonds to Hydrogen.-NH

and NH, Species. Walsh’s rules have been applied to NH,, and the computed geometry is in agreement with that predicted by more accurate calculations.’l The use of an argon laser has allowed the photoelectronic spectra of NH; and NH- to be measured and the electron affinities to be determined: EA(NHZ) = 0.779 f 0.037 eV and E,(NH) = 0.38 f0.03 eV.” NH,. SCF calculations on NH, have given good agreement with experimentally obtained properties. Inclusion of nitrogen d -orbitals into the basis set produces an angular effect which tends to reduce the calculated HNH internuclear angle to a value significantly closer to the experimental angle than is predicted when d-orbitals are not in~luded.’~ Ab initio c a l ~ u l a t i o n ~ ~ of the diamagnetic susceptibility of the ammonia molecule gives the following results: xzz = -14.64 x lo-“ c.g.s. units (along the C , axis), xxx= xrY= -14.94 x and the total susceptibility is -14.84 x lo-“ c.g.s. units, compared with an experimental value of -16.3( f0.8) X c.g.s. units. The kinetics of the synthesis of ammonia in the presence of an industrial catalyst have been in~estigated.’~ The study was performed in a flow system at various working temperatures. The kinetics and mechanisms of several reactions of NH, have been studied,26including: 2N0, + 2NH, + H,O = NH,NO, + NH,NO, 2NH3+ 3s0, = (NH,),S,O, + HNSO SO, + 2NH.3+ H,O (NH,),SO.3 The solid products in the reactions with SO, depended on the partial pressures of the reacting gases. A low-temperature study of the ternary system N,H,-NH,-H,O has revealed seven solid phases; below -80 “C anhydrous N,H, is precipitated from ~olution.~’ Since it is of importance in ”

lo 2”

’* 23 24

25

27

R. A. Young, J. Clzeni. Pliys.. 1974, 60, 5 0 5 0 . J. M. Roscoe and S. G. Roscoe, Canad. J. Chern., 1973, 51, 3671. W. E. Jones and M. Rujimethabhas, Canad. J. Chem., 1973, 51, 3680. F. W. Froben, Ber. Bunsengesellschaft phys. Chem., 1974, 78, 184. E. Wasserman, Chem. Phys. Letters, 1974, 24, 18. R. J. Celotta, R. A . Bennet, and J. L. Hall, J . Chem. Phys., 1974, 60, 1740. J. D. Petke and J . L. Whitten, J . Chem. Phys., 1973, 59, 4855. S. S. Chang and H. F. Hameka, J . Chem. Phys., 1973, 59, 3297. D. B. Kazarnovskaya, R. M. Atamanovska, E. I. Bomshtein, E. A. Slavskaya, and V. A. Dronova, Russ. J. Phys. Chem., 1973, 47, 813. J. Harber, J. Pawlikowska-Czubak, A . Pomianowski, and J. Najbar, 2. anorg. Chem., 1974, 404, 284. M. Sieprawski and R. Cohen-Adad, Bull. SOC. china, France, 1973, 2630.

Elements of Group V 317 atmospheric photochemistry, the kinetics of the reaction of NH, with OH radicals have been studied.” When chlorine and NH, are deposited in a nitrogen matrix at 2 0 K , shifts in the vibrational frequencies of NH, and an absorption at 460cm-’ (assigned to a Cl-C1 stretch) are observed and explained in terms of the formation of a charge-transfer complex between ammonia and ~hlorine.’~ The rate of decomposition of NH, (diluted with Ne) has been measured mass-spectrometrically between 2300 and 3200 “C and is described by a second-order rate equation.,’ It has been found that intermittent operation of a discharge in the decomposition of ammonia, in the presence of alkali, nearly doubles the concentration of hydrazine in the gas.31 It has been concluded that in the second-order kinetics of the decomposition of ammonia under silent electric discharge, the NH, molecules play the role of sharing the de-excitation or neutralization energies of NHT and NH: .32 The yield of solvated electrons has been measured in the pulse radiolysis of liquid ammonia in two independent The results agree, within experimental error. It has been suggested that the large difference in volume expansion for the solvated electron in ammonia and water is because of the different intermolecular interactions in the two liquids.,’ The inhomogeneous model of metal-ammonia solutions satisfactorily explains .~~ the temperature and pressure coefficient of the electrical c o n d u ~ t i v i t yThe activity of. sodium in liquid ammonia has been dete~mined.,~Magnetic susceptibility measurements of Na-NH, and Cs-NH, solutions over a range of concentrations reveal that the susceptibility increases with the concentration of the metal. For very concentrated solutions, the susceptibility approaches that expected for a free-electron gas, and the temperature coefficient is of the same order of magnitude as for the corresponding liquid alkali In a continuation of this work, 13,Cs and ‘“Nn.m.r. measurements have allowed the electron density at the nucleus to be calc~lated.,~ Further work has been carried out on the Raman spectra of solutions of simple salts in liquid ammonia. Polarized low-frequency bands were assigned to metal-nitrogen symmetric stretching vibrations, and suggest unusual co-ordination numbers for Zn2+,Hg”’, and Ag’. Also, ion-association R. Zellner and I. W. M. Smith, Chem. Phys. Letters, 1974, 26, 72. G. Ribbegard, Chem. Phys. Letters, 1974, 25, 333. 30 G.A. Vompe, Russ. J. Phys. Chem., 1973, 47, 715. 3 1 V. L. Syaduk and E. N. Erernin, Russ. J. Phys. Chem., 1973, 47, 864. 32 T. S. Rao and A. V. Kaulgud, Z . phys. Chem. (Leipzig), 1973, 254, 318. 33 Farhataziz, L. M. Perkey, and R. R. Hentz, J. Chem. Phys., 1974, 60, 717. W. A. Seddon, J. W. Fletcher, F. C. Sopchyshyn, and J. Jevcak, Canad. J. Chem., 1974, 52, 3269. 35 N. V. Cohan, G. Finkelstein, and M. Weissrnann, Chem. Phys. Letters, 1974, 26, 93. 36 J. P. Lelieur, J. Chem. Phys., 1973, 59, 3510. 37 G. Lepoutre, M. Debacker, and A. Demortier, J. Chirn. phys., 1974, 71, 113. 38 J. P. Lelieur and P. Rigny, J. Chem. Phys., 1973, 59, 1142. 39 J. P. Lelieur and P. Rigny, J. Chem. Phys., 1973, 59, 1148.

*’

3 18 Inorganic Chemistry of the Main-group Elements effects are smaller than in aqueous ~ o l u t i o n . ~The ' optical spectra of Na-NH, solutions provide data which fulfil the expectations of a twoabsorber model .,' Pulse radiolysis of alkali-metal amides in ND, gives a primary product suggested to be (earn)-,which decays in microseconds to give a n equilibrium mixture of (earn)-and a metal-electron species.42Studies have been made of the behaviour of the silver e l e c t r ~ d e ,and ~ of the Cu1'ICu1lCu0 in acid solutions of liquid ammonia. A review has appeared of the chemistry of bis(trifluoromethy1)aminoc~mpounds."~ NH:. The barriers to rotation for the NH: ion in the ordered and disordered phases of NH4Cl and NH,Br have been calculated from their torsional frequencies and the results compared with the activation energies determined from n.m.r. Neutron quasielastic scattering has been used to probe the reorientations of NH: ion in a single crystal of ammonium b r ~ m i d e . "A~ Raman study of the phase transitions in NH,Br has been undertaken over a range of temperature and pressure. It was found that the ordered phase 0,,is cubic, and that in this phase the NH' ions are

Trialkyl(dialkylsulphoniomethyl)ammonium bis(tetrafluorob0rates) (3) have been obtained by the reaction of dialkyl(alkylthiomethy1)amines (4)or R

\ /

N-CHZ-SR

R' (3)

(4)

[R,NCH,SRI+ salts with trialkyloxonium tetrafluoroborates. The reaction has been generalized to give many NH,OH and Deriuatiues. The reaction: 4Fe3++2NH,OH+ = 4Fe2++ N,O

+ 6H' + H,O

has been used for a long time for the quantitative determination of hydroxylamine. It has been found that the reaction is complicated, but the 40

41 42

43 44

45 46

47 48

4y

P. Gans and J . B. Gill, J.C.S. Chem. Comm., 1973, 914. G. Rubinstein, T. R. Tuttle jun., and S. Golden, J . Phys. Chem., 1973, 77, 2872. W. A. Seddon, J. W. Fletcher, J. Jevcak, and F. C. Sopchyshyn, Canad. J. Chem., 1973, 51, 3653. 0. R. Brown and S. A. Thornton, J.C.S. Faraday 1, 1974, 70, 1009. 0. R. Brown and S. A. Thornton, J.C.S. Faraday I, 1974, 70, 1269. H. G. Ang and Y. C . Syn, Adu. Inorg. Chem. Radiochem.. 1974, 16, 1. D. Smith, Chem. Phys. Letters, 1974, 25, 497. R. C. Livingston, J. M. Rowe, and J. J. Rush, J. Chem. Phys., 1974, 60, 4541 C. H. Wang and R. B. Wright, J. Chem. Phys., 1974, 61, 339. H. Bohme, G. Dahler, and W. Krack, Annalen, 1973, 168.

Elements of Group V

319

Figure 1 Environment of the N(l)H,OH+ ion in NH,0HC104 (Reproduced by permission from Acta Cryst, 1974, B30, 1167) first step is probably the formation of a metal-hydroxylamine complex.5o The decomposition of NH,OH in an alkaline medium is first-order with respect to [NH,OH] and third-order with respect to [OH-]. Decomposition is catalysed by various cations (e.g. Cu2+,Co2+,and particularly Fe2+),the catalysing ions strongly affecting the proportion of Nz and N,O in the products. Probable intermediates are suggested to be metal complexes of nitrosoh y d r ~ x y l a m i n e .The ~ ~ reaction of NH,OH and [Ni(CN)4]2- in an inert atmosphere gives N, and NH3, with tricyanonitrosonickelate as a probable reaction intermediate.s2 The hydrogen-bonding network in the phase of NH,OH'ClO; that is stable at 25 "C has been probed by a three-dimensional neutron-diffraction study. Two crystallographically different NH,OH+ ions are present in the lattice (Figures 1 and 2), there being 12 hydrogen bonds between the

03

Figure 2 Environment of the N(2)H30H+ion in NH30HC104 (Reproduced by permission from Acta Cryst., 1974, B30, 1167) 51 52

G. Bengtsson, Acta Chem. Scand., 1973, 27, 1717. S. Lunak and J. Veprek-Siska, Cofl. Czech. Chem. Comm., 1974, 39, 391. J. Veprek-Siska, and S. Lunak, Coll. Czech. Chem. Comm., 1974, 39, 41.

Inorganic Chemistry of the Main-group Elements NH,OH' ions and the C10, ions, and one hydrogen bond between the NH,OH' ions.53 Krueger and co-workers have, this year, made notable investigations of nucleophilic substitution o n n i t r ~ g e n ~ and ~ - ~ have ' used as their example the reactions of hydroxylamine-0 -sulphonate ion, H,NOSO;. The reactions generally follow a rate law of the type -d[H2NOSO;]/dt = k2[H2NOSO;] x [Nucleophile]. The solvent systems used included H 2 0 ,H,O-methanol, and H,O-DMSO, and a significant decrease in the reactivity of H,NOSO, resulted upon protonation of the nitrogen lone pair to form H,NOSO,. Deuterium isotope effects o n the rate constant were also investigated. In one case the novel cation [(H,N),CSNH,]' was isolated, as the sulphate salt, by the reaction of H,NOSO; and thiourea.55In all cases the reactions were interpreted in terms of nucleophilic substitution on nitrogen, with SO:- as the leaving ion, and the rate constant was taken as a measure of the relative nucleophilicity towards N"'. An order of nucleophilicity was established:

320

H,NOSO;, EtS- - Ph,P > (H,N),CS > -0,SS- > I-( > Br > C1-) > Et,N > HONH, > OHin which there is a range of reactivity of 10". The order is qualitatively parallel with that established for sp3 carbon, peroxide oxygen, and platinum(r1) as electrophilic centres. It was suggested that for substitution on NIII, in compounds of the type NH,-X, polarizability of the nucleophile plays a major role, with basicity making a minor contribution. N,H, and its Derivatives. A new, improved preparation of di-imine has allowed Willis et a2. to extend considerably our knowledge of the chemistry of the isoelectronic nitrogen analogue of ethylene, N,H,. Di-imide was found to be much more stable than has generally been supposed, having a lifetime of minutes at room temperature. Thus, extensive investigation has been possible with free di-imide rather than in a reaction medium; handling techniques, analysis, electronic absorption spectrum, magnetism, and mode of decomposition have been studied in detail.58 The near-u.v. absorption spectrum of N,H, vapour has been re-investigated and the transition assigned to a 'B,+ 'A,(T*+ n,) transition. It was calculated that in the upper state the N-N bond is lengthened by approximately 0.05 A and the DifferH-N=N angle is 132k2" (25" greater than in the ground ences between the near-u.v. spectrum of N,H, in the gas phase and in liquid ammonia have been attributed to hydrogen bonding, and the decomposition of N,H, in liquid NH, has been studied in detail."' Wiberg"' has described in '' E. Prince, B. Dickens, and J. J. Rush, Acta Cryst., 1974, B30, l i 6 7 . 54

5s

'' 57

''

59

6o 61

J. H. Krueger, P. F. Blanchet, A. P. Lee, and B. A. Sudbury, Inorg. Chem., 1973,12,2714. P. F. Blanchet and J. H. Krueger, Inorg. Chem., 1974, 13, 719. B. A. Sudbury and J. H. Krueger, Inorg. Chem., 1974, 13, 1736. J. H. Krueger, B. A. Sudbury, and P. F. Blanchet, J. Amer. Chem. SOC., 1974, 96, 5733. C. Willis and R. A. Back, Canad. J. Chem., 1973, 51, 3605. R. A. Back, C. Willis, and D. A. Ramsay, Canad. J. Chem., 1974, 52, 1006. R. A. Back and C. Willis, Canad. J . Chem., 1974, 52, 2513. N. Wiberg, G. Fischer, and H. Bachhuber, Chem. Ber., 1974, 107, 1456.

Elements of Group V 321 detail his work on di-imide, which had previously been reported only in the form of notes. A general valence force field for the in-plane motions of N,H, has been determined from a total of 24 vibrational frequencies of HNNH, HNND, DNND, and the "N-substituted counterparts.62 The Raman spectra of polycrystalline CH,N=NCH, and CD,N=NCD, have been examined at liquid-nitrogen temperatures and a force field has been c o m p ~ t e d . " ~ An X-ray analysis64of bis(trimethylsily1)di-imine, Me3SiN=NSiMe3, has revealed the crystal structure. Figure 3 gives a view of the molecule, which

Figure 3 Structure of bis (trirnethylsilyl)di-irnine (Reproduced by permission from Acta Cryst., 1974, B30, 1806) has crystallographically imposed C ( o r ?) symmetry. While the N-N bond is very short (1.17 A), the Si-N bond is long (1.81 A) and the SiNN angle is 120". N,H, and Derivatives. The directional components of the barrier to rotation in N,H, have been investigated and, as might be anticipated, the repulsion of the lone pairs appears to be significant, the form with perpendicular lone pairs being The protonation constants and the activity coefficients of hydrazine molecules and hydrazinium ions have been measured in aqueous solution with NaCl at ionic strengths in the range 0.05-3.00mol1-'."" When N,H, was studied by flash photolysis, absorptions attributable to NH, and NH radicals were observed, together with a continuous absorption, whose intensity increases in the u.v., which was suggested to be produced by N&."' Hydrazine decomposition has been studied in the 62

63 64

65 66

67

J. W. Nibler and V. E. Bondybey, J. Chem. Phys., 1974, 60, 1307. R. A. R. Pearce, I. W. Lewis, and W. C. Harris, J. Chem. Phys., 1973, 59, 1209. M. Vieth and H. Barnighausen, Acta Cryst,, 1974, B30, 1806. R. G. Jesaitis, Theor. Chim. Acta, 1973, 32, 71. ' N. P. Komar', V. A. Naumenko, and E. M. Sokol'skaya, Russ. J. Phys. Chern., 1973, 47, 1588. M. Arvis, C. Devillers, M. Gillois, and M. Curtat, J . Phys. Chem., 1974, 78, 1356.

322

Inorganic Chemistry of the Main -group Elements temperature range 60-160°C, together with a study of the catalytic effect of several heavy metals.68 The crystal structure of N,H,F reveals individual N2Hf and F- ions held together by hydrogen bonds.69 After collection of a new set of X-ray diffraction data, the structure of Li(N,H,)SO, has been refined to a stage where comparison with neutron-diff raction results is meaningful. It was noted that the N-H bond lengths are systematically shorter, as determined from the X-ray measurement^.'^ The crystal structure of tetraformylhydrazine has been determined by X-ray analysis. The molecules consist of two planar N(CHO), groups, which are arranged perpendicular to each other (Figure 4). The bond lengths are: N-N = 1,346, C-N = 1.348, and C-0 = 1.295 A.”

Figure 4 Molecular structure of tetraformylhydrazine (Reproduced by permission from Chem. Ber., 1974, 107, 492) Silylated (and germylated) hydrazines have been prepared by the addition of Ph,SiH, and similarly substituted silanes, to the N=N bond of diethyl and dimethyl azodicarboxylates. Spectroscopic data support formulations (5) and (6), and a radical mechanism could be substantiated for hydrosilylation whereas the addition of germanes proceeded via polar intermediate~.~~ h8 69

70 71 72

R. Maurel, J.-C. Menezo, and J. Barrault, J. Chim. phys., 1973, 70, 1221. L. Golic and F. Lazarini, Monatsh., 1974, 105, 735. M. R. Anderson and I. D. Brown, Acta Cryst., 1974, B30, 831. A. Hinderer and H. Hess, Chern. Ber., 1974, 107, 492. K.-M. Linke and H. J. Gohausen, Chem. Ber., 1973, 106, 3438.

323

Elements of Group V R R

I

R2 R2

I

RjSi-N-N-H

Ph,Si-N-N-H

I

I

Ph S'

21-1

(5)

I

N-N-H

I

R R (6)

Bonds to Nitrogen.-Azides. A n electron-diff raction study of gaseous cyanogen azide has revealed that, as in chlorine azide, the azide grouping is non-linear. Figure 5 shows the dimensions found in this ~ t u d y . ' ~ 19.2(1.6)

1.355(2

Figure 5 Geometry of cyanogen azide (Reproduced by permission from Acta Chem. Scand., 1973, 27, 1531) By collecting data at 100 K, the X-ray crystal structure of methylmercuric azide has been determined. The results, while not having the usual accuracy associated with routine X-ray analyses, do show that the H,C-Hg-N grouping is essentially linear (Figure 6)."

aN

Figure 6 Geometry of methylmercury azide (Reproduced by permission from 2. Naturforsch., 1973, 28b, 426) The structure of crystalline hydrazinium azide (N,H,) consists of linear azide ions and almost perfectly staggered N,H; ions. The ions are held together by an intricate three-dimensional network of hydrogen bonds, not all of which are the same. Figure 7 shows a view of the structure (the space group chosen was P 2 J b , with y = 114.0", rather than the more usual P ~ J C ) . ~ ~

73 74 75

A. Alemenningen, R. Bak, P. Jansen, and T.G. Strand, Acta Chem. Scand., 1973,27, 1531. U. Miiller, Z . Naturforsch., 1973, 28b, 426. G. Chiglien, J. Etienne, S. Jaulmes, and P. Laruelle, Acta Cryst., 1974, BJO, 2229.

3 24

Figure 7 Structure of hydraziniurn azide (Reproduced by permission from Acta Cryst., 1974, B30, 2229) The standard heats of formation of hydrazinium azide (AH:= 58.9 f0.4 kcal mol-I) and its monohydrazine adduct (AH:= 70.3 0.8 kcal mol-') have been d e t e ~ m i n e d . ~ ~ Trace amounts of Fe'- have dramatic effects on the thermal decomposi. ~ single~ tion of a-Pb(NJ2, and these effects have now been q ~ a n t i f i e d A crystal X-ray method has been used to determine the anisotropic thermal expansion coefficients of orthorhombic CY -Pb(N3)*in the temperature range 102-423 K.'" The low-temperature (probably orthorhombic) phase of TIN, has been investigated at 25 K intervals down t o 133 K. Single crystals d o not survive the transition from the room-temperature tetragonal phase, and therefore the low-temperature results are based o n X-ray powder data.7yA d.t.a. study of TIN, at low temperatures and elevated pressures has clarified previous, apparently contradictory, conclusions about the phase diagram of TlN,.*" The production of barium pernitride by thermal decomposition of

*

76

E. P. Kirpichev, A. P. Alekseev, Yu. I. Rubtsov, and G. B. Manelis, Russ. J. Phys. Chem., 1973, 47, 1654. " R. W. Hutchinson and F. P. Stein, J. Phys. Chern., 1974, 78, 478. '' F. A. Mauer, C. R. Hubbard, and T. A. Hahn, J. Chern. Phys., 1974, 60, 1341. '' F. A. Mauer, C. R. Hubbard, and T. A. Hahn, J. Chem. Phys., 1974, 59, 3770. C. W. F. T. Pistorius, J . Chern. Phys., 1974, 60, 3720. '()

Elements of Group V 325 barium azide has been studied. Hydrolysis and ammonolysis of the pernitride were also investigated." When thin films of lead azide are photodecomposed, changes occur in the far-i.r.** and near-i.r.', absorption spectra. Although the process is inhomogeneously distributed, the long-time hyperbolic decay on photodecornposition was explicable. A study of the photolysis of zinc azide suggests that diffusion of gaseous nitrogen from the site of generation of nitrogen t o the surface of crystallites could determine the rate of evolution of A detailed single-crystal Raman and i.r. study of Ba(N,), has been made for all polarization orientations in the N; symmetric stretching frequency region (1200-1400 cm-'). A n interesting intensity anisotropy of the band at 1347 cm-' has been observed with respect to polarization along the c direction.85 A series of metal azide salts [e.g. KN, and Ba(N3)J and azido-complexes [e.g. K2Zn(N3)4and KCo(N,),] have been studied by ESCA. In each case two N l s peaks were observed, corresponding t o the central and the two terminal nitrogen atoms, the area of the latter peak being 1.89 times the area of the former. The binding energies of the N l s electrons in the complexes are hardly shifted from those observed for ionic azide, suggesting that the perturbation of the azido-groups by the central metal in the complexes is slight.86 Other Species. Calculations have been performed for various structures of N:, N4, and N,; all have energies above that of N,." The thermal decomposition of h1-3,3,4,4-tetrafluorodiazetidine: F,C-CF,

I

N-N

I

-

CZF4 + N,

is a unimolecular process, and the kinetic parameters have been evaluated .88 Bonds to Oxygen.--"O shifts have been reported for several nitrogenoxygen species, including N z0 3 ,N,04, NO:, and NOC1, with 1 7 0 in natural abundances, some measurements being repeats of earlier work. The oxygen resonances tend to move downfield as the lowest-energy electronic absorption moves to longer wavelengths, but the scatter is large. The relative importance of the orbital terms that contribute to u p is compared for oxygen and n i t r ~ g e n . ' ~

'' S. Salot and J. C. Warf, Inorg. Chem., 1974, 60, 1776. '' S. P. Varma, F. Williams, and K. D. Moller, J. Chem. Phys., 1974, 60, 4950. 83 84

R5 86 87

89

S. P. Varma and F. Williams, J. Chem. Phys., 1974, 60, 4955. S . R. Yoganarasimhan and R. K. Sood, Inorg. Nuclear Chem. Letters, 1973, 9, 1049. 2. Iqbal, J. Chem. Phys., 1974, 61, 1230. H. P. Frizter, D. T. Clark, and I. S. Woolsey, Inorg. Nuclear Chem. Letters, 1974, 10, 247. J. S. Wright, J. Amer. Chem. SOC.,1974, 96, 4753. J. J. Cosa, H. F. Gsponer, E. H. Staricco, and C. A. Vallana, J.C.S. Faraday 1, 1973, 69, 1817. L.-0. Anderson and J. Mason, J.C.S. Dalton, 1974, 202.

326

Inorganic Chemistry of the Main-group Elements

N,O. The fixation of nitrogen as nitrous oxide has been accomplished by a new homogeneous reaction which takes place at atmospheric pressure. Use was made of hydrogen peroxide to effect the oxidation N, + H,02 = N,O

+ H,O

and the reaction is of obvious i m p ~ r t a n c e . ~ ' Dielectric and pressure virial coefficients of N,O have been measured at 6.5, 30.1, and 75.1 "C. The dipole moment, polarizability, and molecular cm3, and quadrupole moment were determined to be 0.18 D, 3.03 x 3.4 x lopz6e.s.u. cm', respectively." A lower limit of -0.15 *O.l e V has been calculated for the molecular electron affinity of N 2 0 , using molecular beam studies.y2 The enthalpy-pressure behaviour for N,O along eleven isotherms in the vapour phase has been determined from measurements of the Joule-Thomson G Values have been obtained for the products of y-radiolysis of liquid N,O.'" Photon yields for the reaction of Ba with N 2 0 have been determined by observing chemiluminescence from flames in a rapid flow of buffer gas,95 and a mechanism for the reaction has been The effects of temperature, initial pressure, and annular width upon the electric breakdown of N,O in a n alternating potential have been studied, and a rate constant has been evaluated." NO. A lower limit of 0.1 f 0.1 e V has been obtained f o r the electron affinity of ~ 0 . " ~ Thermally activated (450 "C) coprecipitated Sn0,-CuO gels show high activity and selectivity for N, formation, at low temperature (150 "C), in the catalytic reduction of N O with C 0 . 9 8 Independently, Hungarian workers have found that SnO,, containing small amounts (0.1-1 mole%) of Cr,O, deposited o n the surface, has a similar effect on the r e a ~ t i o n . ' ~ Mass spectrometry has been used to detect N O in Cl, produced by the electrolysis of molten NaCl. Presumably the N O was produced from nitrogen in the atmosphere."'0 Isotopic redistribution has been found to occur when N O decomposes to its elements in a n a x . discharge.'"' When N O and H, (or D2) are photolysed, or subjected to a microwave discharge, in an YO

M. F. Nagiev, T. M . Nagiev, F. A. Aslanov, V. M. Bairamov, and R. A. Iskenderov, Doklady Chem., 1973, 213, 926. 91 S. Kirouac and T. K. Bose, J. Chem. Phys., 1973, 59, 3043. 92 S. J. Nalley, R. N. Crompton. 13. C. Schweinler, and V. E. Anderson, J . Chem. Phys., 1973, 59, 4125. 93 R. A. Dawe and P. N . Snowdon, J.C.S. Faraday I , 1974, 70, 1269. y 4 T. E. M. Sambrook and G. R. Freeman, J . Phys. Chem., 1974, 78, 28. 95 C. R. Jones and H. P. Broida, J. Chem. Phys., 1974, 60, 4369. " R. W. Field, C. R. Jones, and H. P. Broida, J . Chem. Phys., 1974, 60, 4377. 97 G . Lacaste and R. Bes, Rev. Chim. rnintrale, 1974, 11, 141. ')M. ' J. Fuller and M. F. Wanvick, J.C.S. Chem. Comm., 1974, 57. 99 F. Solymosi and J. Kiss, J . C . S . Chem. Cornm., 1975, 509. 100 F. Lantelme and M. Chemla, Bull. SOC.chim. France, 1974, 773. I01 G. Lacoste. H. Olive. and R. Routik, Cornpt. rend., 1974, 279, C, 257,

Elements of Group V

327

inert matrix at 4-14 K, HNO is formed. Isotopic studies have enabled an assignment to be made of the vibrational spectrum.lo2Configuration interaction calculations of some observed states of NO-, NO, NO', and NOZ+have been made, and the results compared with spectroscopic results.103 N0,-Nz04. Last year it was reported that (NO,),, present to a small extent in gaseous NO,, was non-polar, and a structure involving a six-membered N-0 ring system was postulated. Liebmanlo4has suggested a pyramidal structure for (NO,),, with the same connectivity, to explain the total electron content of the polymer. This structure, it was suggested, would have a very low dipole moment. The original authors have replied'"' to this suggestion and commented that their technique is capable of detecting a moment of 0.1 D. A study of the pyrolysis of NO2 in a shock tube has shown that at temperatures of 1500-2300 K the kinetics involve the dissociation of NO, in addition to the steps proposed at lower and higher temperatures. The rate of: NO, +NO, = NO +NO, was found106to be somewhat faster than expected by extrapolation from experiments near to 600 K. The molecular electron affinity of NO, has been found9' to have a lower limit of 2 . 5 i ~ 0 . 1eV, from collisional ionization data, and a value of 2.36*0.1 eV has been obtained by photodetachment from NO;.'"' Th'e ionization potential of NO, has been found to be 9.62eV by photoionization mass spectrometry.lo8 A detailed study of the i.r. spectrum of Nz04, combined with a previous Raman study, has allowed a reliable determination of all the fundamental vibrational frequencies of N,04. Observation of a band assigned to a torsional mode has allowed an estimate to be made of 2-3 kcal mol-' for the height of the barrier to rotation, and a further discussion of the bonding in N,04 to be pre~ented.'~' The pure rotational Raman spectrum of NO, has been observed and shown to be consistent with the existing determinations of molecular parameters. The study, having included work on the rotational resonance Raman spectrum of NO,, led to a simplified statement of the selection rules for resonance rotational Raman spectra of asymmetric t0ps.l'' Argonmatrix-isolated samples of NO, show a Raman spectrum which is in marked M. E. Jacox and D. E. Milligan, J. Mol. Spectroscopy, 1973, 18, 536. P. W. Thulstrup, E. W. Thulstrup, A. Andersen, and Y. Ohm, J. Chem. Phys., 1974, 60, 3975. 104 J. F. Liebrnan, J. Chem. Phys., 1974, 60, 2944. 105 S. E. Novick, B. J. Howard, and W. Klemperer, J. Chem. Phys., 1974, 60, 2945. lo6 P. K. Butt and B. P. Levitt, J.C.S. Faraday I, 1973, 69, 1957. lo' E. Herbst, T. A. Patterson, and W. C. Lineberger, J. Chem. Phys., 1974, 61, 1300. 108 P. C. Killgoar, jun., G. E. Leroi, W. A. Chupka, and J. Berkowitz, J. Chem. Phys., 1973,59, 1370. C. H. Bibart and G. E. Ewing, J . Chem. Phys., 1974, 61, 1284. ' l o G. R. Bird and M. J. Marsden, J. Mol. Spectroscopy, 1974, 50, 403. lo' I 03

Inorganic Chemistry of the Main-group Elements 328 contrast t o that observed for gas-phase samples. The matrix-isolated samples give sharp lines, with no intense fluorescence lines. O n allowing the matrix to warm, the three symmetric N,O, modes increase in intensity at the expense of the NO, bands."' A microwave-optical double resonance and fluorescence study has been made of NOz, using the 4579 A line of the argon-ion laser.112The X-band e.s.r. spectrum of NO, has been investigated . I ' The intramolecular potential-energy function recently proposed by Anderson has been applied to NO, and the other bent molecules SO, and 0,.114

It has been found that heat is absorbed when N,04 is mixed with non-polar non-donor liquids, and is evolved on mixing NzO4 with polar or donor liquids. Heats of mixing at different concentrations of 16 binary mixtures containing N,O, have been reported."' An e.s.r. study has been made of the reaction of NO, with metal acetylacetonates. Those complexes of metals which have stable lower oxidation states (i.e. Cu", Fe''', CoIII, and VO") react t o form iminoxy radicals, while those metals which are not readily reduced (e.g. Zn", Cr"', and Ce"') do not give iminoxy radicals."6 The kinetics of the synthesis of nitrogen oxides in an ozonizer, when 0, is electro-synthesized from air, have been reported.'" Smardzewski has produced several reports of work o n nitrogen hypofluorite, NOF."8-'2n Simultaneous deposition of F, and NO in A r and N, matrices at 8 K produces species that give three new i.r. absorptions in addition to the normal F-N-bonded FNO. Isotope studies help to assign these bands to the isomer NOF, which appears to be a bent molecule, undergoing photorearrangement to the more stable FNO on exposure to radiation below 2 8 0 n m . Similarly, the isomer of nitryl fluoride O N O F has been detected at low temperatures.12n"21 Bibart and Ewing have complemented their work on the vibrational spectrum of N,O, by studying gaseous N,O,. The spectrum revealed new, previously unreported, features and allowed a total assignment to be made. Also, the barrier to internal rotation was estimated to be ca. 1 kcal mo1-'.122 Silver hyponitrite, a useful synthetic reagent, has been prepared by a new

"'

D. E . Tevault and L. Andrews, Spectrochim. Acta, 1974, 30A, 969. T. Tdnaka, K. Abd, and R. F. Curl, J. Mol. Spectroscopy, 1974, 49, 310. 'I' D. S. Burch, W. H. Tanttila, and M. Mizushima, J. Chem. Phys., 1974, 61, 1607. 'I4 V. K . Wang and J. Overend, Spectrochim. Acta, 1974, 30A, 237. '15 C. C. Addison, J. C. Sheldon, and B. C. Smith, J.C.S. Dalton, 1974, 999. 'I6 W. H. Wolodarsky, J. Faniran, and J. K. S. Wan, Canad. J. Chern, 1973, 51, 4072. 117 0. M. Knipovich, Yu. M. Emel'yanov, and Yu. V. Filippov, Russ. J. Phys. Chem., 1973, 47, 1474. R. R. Smardzewski and W. B. Fox, J. Amer. Chem. Soc., 1974, 96, 304. ' I 9 R. R Smardzewski and W. B. Fox, J. Chern. Phys., 1974, 60, 2104. "(' R. R. Smardzewski and W. B. Fox, J.C.S. Chem. Comm., 1974, 241. 12' R. R. Smardzewski and W. B. Fox, J. Chern. Phys., 1974, 60, 2980. 1 2 2 C. H. Ribart and G. E. Ewing, J. Chem. Phys., 1974, 61, 1294.

Elements of Group V 329 convenient synthesis. The sodium salt is made by the reaction of NO with Na metal, in an organic solution containing benozophenone, and is then allowed to react with AgNO, to give the silver hyp~nitrite."~ The reduction of HNO, by Fez+ at p H 5 gives NO, N 2 0 , and N, as gaseous products. Two simultaneous reactions appear to be taking place: reduction to NO then to N 2 0 , and reduction to N, directly.""

Nitric Acid and Nitrates. The unimolecular thermal decomposition of HN03, highly diluted in Ar, in shock waves has been studied and a mechanism The influence of the gaseous-phase composition (NO, NO,) and the gas-liquid contact time on the rate of the N0,N02HNO, isotopic exchange has been measured, and the influence of the HNO, on the "N/'"N isotopic exchange between NO and dilute HNO, has also been measured. A mechanism of the NO-HNO, exchange has been discussed.'26The rate of NO; ion formation is the rate-determining step in the nitration of toluene with mixed acid under certain conditions, and values of the rate constant have been determined for the first time.'" Using the literature data for the concentrations of the non-hydrated acid in the HNO,-H,O system, its states in the €€NO,-H,SO,-H,O system, and its partial vapour pressures, the applicability of Henry's law has been demonstrated to non-hydrated nitric acid in these systems.12' On the basis of a studylZ9of the systems HNO,-H,O-M(NO,), (Mn+= Na', Cuz+,Be2+, UO:+, La3+,Fe3+,or AI3'), the salting-out activity of the nitrates is characterized by the separation coefficient I described by: log I = Ac

where A is a constant and c is the concentration of nitrates. The liquidvapour equilibria in the systems Hz0-HN03-M(N03)2 (M = Cu or Be) have also been studied."" Similar work has been carried out with zirconium and hafnium nitrates, using a circulation method.'" The composition of the system N204-H,0-HN03 has been determined with the aid of the relative Raman intensities of the scattering species (e.g. NO', NO;, NzO", HN0,).132 A mass-spectroscopic investigation has been made of the vaporization of CsN03. Although CsNO: was not observed, peaks attributable to Cs2NO:, 123

G. D. Mendenhall, J. Amer. Chem. SOC., 1974, 96, 5000.

A. Chalamet, Annalen., 1973, 353. K. Glanzer and J. Troe, Ber. Bunsengesellschuft phys. Chem., 1974, 78, 71. 126 D. Axente, G. Lacoste, and J. Mehenc, J. Inorg. Nuclear Chem., 1974, 36, 2057. J. W. Chapman and A. N. Strachan, J.C.S. Chem. Comm., 1974, 293. lZ8 I. V. Oknin, Russ. J. Phys. Chem., 1973, 47, 1308. A. N. Efimov, M. I. Zhikharev, and Yu. P. Zhirnov, Russ. J. Phys. Chem., 1973,47, 1662. A. N. Efimov, M. I. Zhikharev, and Yu. P. Zhirnov, Russ. J. Phys. Chem., 1973, 47, 1652. 13' A . N. Efimov, M. I. Zhikharev, Yu. P. Zhirnov, and A. Ya. Chilikin, Russ. J. Phys. Chem., 1973, 47, 1208. 13* R. Audinos, J. Chim. phys., 1974, 71, 117. 12"

330

Inorganic Chemistry of the Main -group Elements

Cs', Cs2NO;, CsO', and NO: were observed, and the enthalpy of vaporization of CsNO, was estimated to be 23.7 (ztl.0) kcal moI-' at a mean temperature of 7 7 0 K.',, Values of the dielectric constant and resistivity measured at 1 kHz have been presented for polycrystalline AgNO,, T1NO3, and NH,NO, below room temperature, and previously published values for the heat capacities examined.", The viscosities of some univalent metal nitrate melts (M = Li, Na, K, Rb, Cs, Ag, or TI) have been measured by the capillary method in the range corresponding to their thermal stability, and equations have been given to represent the observed temperature variation. A correlation was found between the free volume, the force constant of the M-0 bond, and the viscosity of the individual The temperature dependence of the viscosity of the three binary systems LiCI0,-LiNO,, NaC104-NaN0,, and KC10,-KNO, has been c h a r a c t e r i ~ e d . ' ~ ~ The lattice energies of some univalent metal nitrates in calcite-like modifications have been calculated, and the results are in good agreement with experimental data. It was deduced from the temperature dependencies of the energies that there are significant departures from the calcite-type structure at high temperatures in LiNO,, NaNO,, and KNO,. The nature and extent of the deviations were discu~sed.'~' D.t.a. has been used to determine the kinetics of the phase transformations of NH,NO,."x The laser Raman spectra of NH,NO, and ND,NO, have been measured between 210 and 320K.'39 It was shown that the phase transition V-IV is probably a A transition that is due to rotational disorder of NH: ions. The spectra df phase IV are consistent with the space group Pmmm. In the polymorphic phase transformation I1 + I for KNO,, a variety of orientations have been found by polarized-light m i c r o ~ c o p y . ' ~ ~ A review has been published of the equilibrium and transport properties of low-melting mixed metal nitrates (e.g. NaN0, and AgN03).14' Thermodynamic and other experimental data have been taken from the literature and used to construct a 'potential-pO' diagram corresponding to the solvent eutectic Na,KNO, at 229°C. The presence or absence of H,O was taken into account. The representation resolves previous apparent contradictions in the literature and explains the individual behaviour of these The decomposition of MnO; in molten alkali-metal nitrates is a complex 133

134 135 136

13' 138

139 140 14* 142

L. L. Ames, J. J. Ling-Fai Wang, and J. L. Margrave, Inorg. Nuclear Chern. Letters, 1473, 9, 1243. J. H. Fermor and A. Kjekshus, Acta Chem. Scand., 1973, 27, 3712. N. P. Popovskaya and V. G. Smotrakov, Russ. J. Phys. Chern., 1973, 47, 804. A. A. Farmakovskaya and I. A. Brovkina, Russ. J. Phys. Chern., 1973, 47, 757. J. H. Fermor and A. Kjekshus, Acta Chern. Scand., 1973, 27, 1963. D. Fatu, S. Fatu, and E. Segal, Rev. Rournaine Chirn., 1973, 18, 1709. D. W. James, M. T. Carrick, and W. H. Leong, Chern. Phys. Letters, 1974, 28, 117. S. W. Kennedy and M. Odlyla, Austral. J. Chem., 1974, 21, 1121. J. Richter, Angew. Chem. Internat. Edn., 1974, 13, 438. A. de Haan and H. Van der Poorten, Bull. SOC.chim. France, 1973, 2894.

Elements of Group V

331

process involving the reduction of MnVI1to Mn'", which precipitates out of solution. The reduction is by NO;, produced by the thermal decomposition of NO;. A rate law has been established and the catalytic behaviour of several anionic and cationic species inve~tigated.'"~An investigation has been made into the applicability of the Nernst equation to Ag' concentration cells in fused nitrate media. It was concluded that the activity factor for Ag' remains constant in the range lo-"< C S 1 mol kg-'. The deviations from Nernst's equation at very high and very low concentrations have been discussed, and for concentrations of less than lo-" mol kg-' the deviations were attributed to an increment in Ag' content of the melt, mainly by corrosion. 14" The reaction of KSCN with a molten NaN0,-KN03 eutectic proceeds in a complex and relatively violent fashion up to a critical concentration. The reaction yields NO;,S042-, and basic ionic species in the melt and NO,, CO,, (CN),, and N,O as gaseous products. The reaction was interpreted in terms of ionic equilibria involving NOS, NO;, SCN-, Og-' 02-, and 0; ions and 0, as principal reacting species.145When UO, reacted with molten mixtures of alkali-metal nitrates, ternary uranates were identified by X-ray diffraction technique^.'^^ Thermodynamic data have been obtained for the solubilities of H, and CO (often used as fuel gases in high-temperature fuel-cells) in a molten equimolar mixture of NaNO, and KNO,. Both gases react slightly with the solvent: H, +NO; = NO; + H,O

CO +NO;

= NO;

+ CO,

to give 'unusual' solubility kinetic Solubility measurements have been used to investigate the interaction of CO, and NH, in molten alkalimetal nitrates .14' The relative Raman intensity of the v 1 band of NO; has been used to probe metal ion-NO; interactions in AgN0,-alkali-metal nitrate molten mixtures.149A force field has been found which fits the observed lattice frequencies of NaNO,; a short-range-interaction model was used.'" Multiple band structure in the symmetric stretching ( u l ) region of the Raman spectra of R b N 0 3 IV and CsNO, I1 confirms the presence of NO; ions o n three distinct crystallographic C , sites and supports the proposed C', or Ci space group. Assignments were confirmed by ''0 isotopic dilution s t u d i e ~ . ~ " Intensity formulae have been derived for the Raman lines in the polarization spectra of LiNO,. Using the spectra taken from the literature, the 143 144

146

148 149

150 '51

R. B. Temple and G. W. Thickett, Auskal. J . Chem., 1974, 27, 943. B. Holmberg, Acta Chem. Scand. (A), 1974, 28, 284. M. E. Martins, A. J. Calandra, and A. J. Arvia, J. Inorg. Nuclear Chem., 1974, 36, 1705. C. J. Toussaint and A. Avogadro, J. Inorg. Nuclear Chem., 1974, 36, 781. E. Desimoni, F. Paniccia, and P. G. Zambonin, J.C.S. Faraday I, 1973, 69, 2014. F. Paniccia and P. G. Zambonin, J.C.S. Faraday 1, 1973, 69, 2019. A. Eluard, K. Balasubrahmanyam, and G. J. Janz, J. Chem. Phys., 1973, 59, 2756. A. Yamamoto, Y. Shiro, and H. Marata, Bull. Chem. SOC.Japan, 1974, 47, 1105. M. H. Brooker, J. Chem. Phys., 1973, 59, 5828.

332

lnorganic Chemistry of the Main -group Elements DlMERlC ANION AT

C I 000

DIMERIC ANION AT

DlMCRlC ANION AT

[Oit]

Figure 8 Dimensions of the hydroxylamine -NN-disulphonate groups (Reproduced by permission from Inorg. Chem., 1974, 13, 2062)

h

force constants for the crystal were computed.’” LiNO, and KNO? ion pairs have been isolated in argon, glassy water, and glassy ammonia at 12 K and the i.r. spectra measured. A drastic reduction in the splitting of the v , ( e ) nitrate asymmetric stretching mode was observed in the H,O and NH, matrices when compared with the argon cage. This effect was attributed to ”*

S. P. Kumar, V. A. Padma, and N. Rajeswara Rao, J. Chem. Phys., 1974, 60, 4156.

Elements of’Group V 333 the solvation of the cation in the H 2 0 and NH, Detailed i.r. measurements have been made of low-temperature, matrix-isolated methyl nitrate. The results may be of use when considering bonding of nitrate groups to a metal in a unidentate manner.lS4 Trifluoromethyl peroxynitrate, CF,OONO,, has been synthesized from the reaction of trifluoromethyl hydroperoxide with N20, or of fluoroperoxytrifluoromethane with N,04. The vibrational spectrum was assigned based o n a molecule of C, Fremy ’s Salt and Derivatives. Two free radicals were identified by e.s.r. spectroscopy when single crystals of potassium hydroxylamine disulphonate were irradiated with y-rays at 77 K. The identity of the predominant paramagnetic centre remains in doubt, but it appears to be a precursor to Fremy’s radical, [ON(SO,);-], which is also present in small concentrat i o n ~ Gangwer . ~ ~ ~ has carried out similar investigations but using X-irradiation. It was concluded that room-temperature near-neighbour proton and low-temperature radical pair interactions occur in the The crystal structure of Rb5{[ON(S0&]2H},3H20 has been reported. There are two formula units per unit cell (space group PT), and the two {[ON(S03)2]2H}5-anions occupy each of two independent centres of symmetry [at (000) and (Og)]. The two [ON(S03)2]3-groups in each anion are distances joined by a symmetrical hydrogen bond (Figure 8), the 0-H-0’ being 2.41(2) and 2.43(2) Nitrogen Oxides and Atmospheric Chemistry. Perhaps the most significant report in this field has been the publication of the proceedings of the symposium of the International Association of Geomagnetism and Aeronomy (Kyoto, Japan, 1973).159Fifteen papers were presented which contain important information, of which the following might be the most directly relevant: Niki: ‘Reaction kinetics involving 0 and N compounds’; Johnson et al.: ‘Photochemistry of NO, and HNO, compounds’; Akerman et al.: ‘Recent stratospheric spectra of NO and NO,’; Schiff: ‘Measurement of NO, NO2, and HNO, in the stratosphere’; Wofsy et al.: ‘HO,, NO,, and C10,: their role in atmospheric photochemistry’. 153

154

155

156

lS7 15* 159

N. Smyrl and J. P. Devlin, J . Phys. Chem., 1973, 77, 3067. J. A . Lannon, L. E. Harris, F. D. Verderame, W. G. Thomas, E. A . Lucia, and S. Koniers, J. MoE. Spectroscopy, 1974, 50, 68. F. A. Hohorst and D. D . DesMarteau, Inorg. Chem., 1974, 13, 715. R. W. Holmberg and B. J. Wilson, J. Chem. Phys., 1974, 61, 921. T. E. Gangwer, J . Phys. Chem., 1974, 78, 375. R. J. Guttormson, J. S. Rutherford, B. E. Robertson, and D. B. Russel, Inorg. Chern., 1974, 13, 2062. International Association of Geomagnetism and Aeronomy, Symposium Kyoto, Japan, 1973, Canad. J. Chem., 1974, 52, 1381.

3 34

Inorganic Chemistry of the Main-group Elements A new method, based on that of Griess-Saltzman, has been developed for measuring NO, in the atmosphere.160A detailed study has been made of the relative quantum yields for the photolysis of NO, to NO at 5 or 1 0 n m intervals in the range 295-445nm, and also at longer wavelengths. The photodissociation probability of NO, remains close to unity for photolysis by all wavelengths shorter than the dissociation limit at 398 nm.'" The photolysis of low concentrations (0.9-100 p.p.m.) of NO, in air has been investigated and the rate constants of three of the elementary reactions have been directly deterrnined.l6' A preliminary report has appeared of the reaction of NO with vibrationally excited 03.'63 The rate constant for the reaction of 0, with NO, has now been measured over the range of temperature 259-362K and the data have been fitted to the Arrhenius e q ~ a t i 0 n .Graham l~~ and Johnston'6s have also studied this reaction, from 298.2 to 231.4 K. Morris and Niki16" have investigated the mechanism and rate constant of the reaction:

NO2+

0 3

= NO,

0

2

at the p.p.m. concentration level. It was noted that since the reaction is rapidly followed by: NO, +NO, N,O, the observed stoicheiometry ranged from 1.65 to 2.00. While the reaction of NO, with 0, is probably responsible for the catalytic depletion of 0, in the earth's stratosphere, the recombination reactions:

OH+ N O + M and

= HNO,

+M

O H + N 0 2+ M = HNO,

produce more stable products, particularly H N 0 3 ,which does not react with 0,. These termolecular reactions have now been studied (for M = H e , Ar, and N2) at pressures from 1 to 10 Torr and temperatures from 230 to 450 K,'"' and at 296 K over a pressure range 0.4-5 Torr.16R The primary reaction in the photolysis of HN03 vapour by U.V.radiation is : HNO, + hv = HO + N O , and the primary quantum yield is unity. Experimental evidence has been presented in favour of these two conclusions for the wavelengths 200, 255, '"O

"* 163

165 166 167

168

J. Alary, P. Bourbon, P. Chovin, C. Delaunay, J. Esclassan, and J.-C. Lepert, Compt. rend., 1974, 278, C, 651. I. T. N. Jones and K. D. Bayes, J. Chem. Phys., 1973, 59, 4836. D. H. Stedman and H. Niki, J . Phys. Chem., 1973, 77, 2604. R. J. Gordon and M. C. Lin, Chem. Phys. Letters, 1973, 22, 262. R. E. Huie and J. T. Herron, Chem. Phys. Letters, 1974, 27, 411. R. A . Graham and H. S. Johnston, J . Chem. Phys., 1974, 60, 4628. C. H. Wu, E. D. Morris jun., and H. Niki, J. Phys. Chem., 1973, 77, 2507. J. G. Anderson, J. J. Margitan, and F. Kaufman, J. Chem. Phys., 1974, 60, 3310. C. J . Howard and K. M. Evenson, J. Chem. Phys., 1974, 61, 1943.

Elements of Group V

335

290, and 300 nm. The importance of eliminating side-reactions, by careful control of conditions?in the laboratory has been emphasized.16' The conversion of NO into NOz is now considered to be of major importance in the natural and perturbed atmospheres. A kinetic study has been made of the reaction: HO, + N O = NO, + OH using a photochemical "02competitive isotope labelling technique.17' Simonaitis and Heicklen"' have independently studied this reaction and also the reaction between HO, and NO,:

HO, +NO,

= HONO

+ 0,

NO, has been shown to undergo reaction with CH,CHO and GH, a t a much greater rate than the corresponding ozonolysis reactions, and the implications to the production of photochemical smog have been considered.'"

Bonds to Fluorine.-Some 350 lines in the microwave spectrum of NFz have been measured between 13.0 and 65.2 Hz. A complete assignment has been .achieved, and the usual molecular constants, including the average geometry, have been computed. It was confirmed that the ground-state electronic wavefunction transforms as 2 ~ 1 . ' 7 3 Using a new apparatus designed to measure very low gas solubilities (ca. mol fraction), the solubilities of NF, (298-318 K) and N2F, (288318 K) in water have been determined, and the enthalpies and entropies of solution Shock-wave studies have been used to probe the thermal decomposition of NF, and the reactions of NF, and N2F4 with H2.17' Solid NF: salts have been prepared by a new route. When NF3, FZ,and a strong fluorine acceptor (e.g. SbF,) are photolysed by U.V. light, a white solid product forms within seconds. The product is a mixture of NFaSbFi and 0: SbF;."6 Polarization data from a Raman spectroscopic study of gaseous ONF, have allowed the bands at 542cm-' (a,) and 528cm-'(e) to be confidently assigned. Some thermodynamic data were also presented.'" After prolonged photolysis (greater than 60 minutes: 220-900 nm radiation) of matrix-isolated ONF, at 8 K, the i.r. features of FNO began to appear. After 16 h, traces of N O were observed. It was thought, intuitively, that lag "O

17' '71

173

174 175 176 177

H. J. Johnston, S.-G. Chang, and G. Whitten, J. Phys. Chem., 1974, 78, 1. W. A, Payne, L. J. Stief, and D. D. Davis, J . Amer. Chem. SOC.,1973, 95, 7614. E. Simonaitis and J. Heicklen, J. Phys. Chem., 1974, 78, 653. E. D. Morris jun., and H. Niki, J. Phys. Chem., 1974, 78, 1337. R. D . Brown, F. R. Burden, P. D . Godfrey, and 0. I. R. Gillard, J. Mol. Spectroscopy, 1974, 25, 301. C. R. S. Dean, A . Finch, and P. J. Gardner, J.C.S. Dalton, 1973, 2722. G. L. Schott, L. S. Blair, and J. D. Morgan, jun., J. Phys. Chem., 1973, 77, 2823. K. 0. Christie, R. D . Wilson, and A. E. Axworthy, horg. Chem., 1973, 12, 2478. N. Aminaday, H. Selig, and S. Abramowitz, J. Chem. Phys., 1974, 60, 325.

336

Inorganic Chemistry of the Main-group Elements

simultaneous loss of two fluorine atoms would be less likely than a stepwise degradation in which F,NO was formed as a transient intermediate.17'

Bonds to Halogen.-Microwave studies of four isotopic species of NCl, have been used to calculate the structural parameters [r(N-C1) = 1.7535 f 0.0020 A, and angle ClNCl = 107O47'* 20'1, the dipole moment ( F = 0.39* 0.0 1 D), and the N-Cl bond-axis quadrupole coupling constant (- 108f 3MHz).'~~ From a conductance study of the effect of NOCl on SO, in SO, at -20 "C, the compounds NO(SO,),CI (n = 1, 2, or 3) have been isolated. It would appear from conductivity data that NOS0,CI behaves as a weak electrolyte in SO,.'s"The kinetics of atom-exchange reactions among CINO, NO, and NO, have been studied by using a time-of-flight mass spectrometer, and I4N and 15N isotopically labelled species.18' When Cl,O, reacted with NCl,, primary and secondary amine compounds belonging to the class of perchloric acid amides were produced: C1,0,

+ 3NH, = NH4[HN0,C1] + NH4[CI04]

The remaining hydrogen atoms o n N could be replaced by metal cations: N&HN03Cl+ NH4C104 + 3KOH = K2NC103 + 2NH3 + 2H20 It was found that the nature of the N-C1 bond depended o n the other substituents o n the nitrogen.lE2 bond in CF,Photochemical insertion of C O and SO, into the N-CI (FCO)NSO,Cl gave CF,(FCO)NC(O)CI and the unstable CF,(CFO)NS0,CI. Several similar products were also produced.'" Infrared spectra of NI,,3NH3 and N13,3ND3 are similar t o those of (N13,NH3),, and (N13,NDJn, respectively, and in the positions of the N-I vibrations they are identical. It was concluded that all the compounds had a similar skeleton to that which has been established for (NI3,NH3),.lS4The reaction of malonic acid diethyl ester with NI,,3NH3 in liquid NH, at -33 "C produces mainly diaminomalonic acid diamide [(NH2)2C(CONH2)2], iodoform, and ethyl carbarnate."' Organic compounds containing acidic hydrogen attached to carbon undergo iodination when treated with N13,3NH, in liquid NH,; in some cases ammonolysis ensues, and the corresponding amino-compound is isolated as the final product.'s6 "* R. R. Smardzewski and W. B. Fox, J. Chem. Phys., 1974, 60, 2193. G . Cazzoli, P. G. Favero, and A. D. Borgo, J. Mol. Spectroscopy, 1974, 50, 82. R. De Jaeger and J. Heubel, Rec. Trau. chirn., 1974, 93, 80. H. D. Sharma and S. P. Sood, J . Phys. Chem., 1974, 78, 402. '" D. Baumgarten, E. Hiltl, J. Jander, and J. Meussdoerffer, Z. anorg. Chem., 1974, 405, 77. G. H. Sprenger and J. M. Shreeve, J. Amer. Chem. SOC., 1974, 96, 1770. lS4 J. Jander and R. Minkwitz, Z. anorg. Chem., 1974, 405, 250. l S 5 J. Fenner and J. Jander, Z. anorg. Chem., 1974, 406, 153. IX6 J. Fenner and J. Jander, Annalen, 1974, 1253. 179

Elements of Group V

337

2 Phosphorus Phosphides.-The structures adopted by the Zintl phases, i.e. the binary compounds of Group I or I1 metals with the elements from Groups 111-VI of the Periodic Table, have been reviewed, and the bonding has been discussed in terms of the transition between ionic and metallic bonding.lS7 Reactions of red phosphorus with metals continue to be of interest, and rubidium"' and calcium'8y give respectively Rb4P6and Cap,. X-Ray structures are available for both species, the former containing regular planar P6 rings (P-P 2.15 A, in agreement with the presence of multiple bonding) while the latter contains infinite layers of P:- ions. Powder diffraction data for CeP, and PrP, indicate that they are isostructural, belonging to the NdA, structure type.'" The gaseous equilibria shown in equations (1)-(3) have been studied by Knudsen-cell mass ~ p e c f r o m e t r y ,and ~ ~ ~values have been obtained for the dissociation energies (D:) and heats of formation of ASP and BiP (D: 429.7 and 278 kJ mol-l; f i H T 2 9 8 187.0 and 262 kJ mol-', respectively). ASP

Bi, + P,

As + P

(1)

2BiP

(3)

Hydrides.-M.O. calculations have been reported for phosphine'"' and PH,' '93 suggesting small participation of phosphorus 3d -orbitals in the a-bonding. Values of 1.523A and 109.5' are given for r(P-H) and the bond angle in PH: at the optimum geometry. 'Forbidden' rotational transitions, caused by centrifugal distortion, have been observed for PH3,1947195 PD,,195and AsH3,I9' and new structural parameters have been calculated. Accurate measurements have been made of the v, and v4 fundamental vibrational-rotational bands of PH,, yielding further new molecular constants,lY6and a linewidth study of the Raman bands in liquid PH, has enabled the reorientation correlation time to be estimated.'" A number of n.m.r. parameters for PH, can be derived from an analysis of the 'H and 31P n.m.r. spectra of PH, in various isotropic and nematic H. Schafer, B. Eisenmann, and W. Miiller, Angew. Chem. Internat. Edn., 1973, 12, 694. W. Schmettow, A. Lipka, and H. G. von Schnering, Angew. Chem. Internat. Edn., 1974, 13, 345. W. Dahlmann and H. G. von Schnering, Naturwiss., 1973, 60, 518. 190 E. Hassler, T. Johnson, and S. Rundqvist, Acta Chem. Scand. (A), 1974, 28, 123. 19' K. A. Gingerich, D . L. Cocke, and D. Kordis, J. Phys. Chern., 1974, 78, 603. 19* J. D. Petke and J. L. Whitten, J . Chem. Phys., 1973, 59, 4855. 193 Yu. I. Gorlov, I. I. Ukrainsky, and V. V. Penkovsky, Theor. Chim. Acta, 1974, 34, 31. 194 F. Y. Chu and T. Oka, J. Mol. Spectroscopy, 1973, 48, 612. 19' F. Y . Chu and T. Oka, J . Chem. Phys., 1974, 60, 4612. 196 P. K. L. Yin and K. N. Rao, J. Mol. Spectroscopy, 1974, 51, 199. M. Schwartz and C. H. Wang, Chem. Phys. Letters, 1974, 25, 26. lY8N. Zumbulyadis and B. P. Dailey, Mol. Phys., 1974, 27, 633. lX7 188

338

Inorganic Chemistry of the Main-group Elements

Ion-molecule reactions in phosphine at source temperatures greater than 25 "C give the PH; ion, which reacts further with PH, giving P2Hf, P,H,', and P4H;.199With source temperatures below 25 "C, however, similar ions are obtained, but they are solvated with further PH, molecules. Values of the magnetic rotation, p(P-H), which vary markedly with the s-character of the P-H bond have been obtained from a magneto-optical study of compounds in the series PH,X3-,, OPH,X3-,, and SPH,,X3-, ( X = R The barriers to internal rotation and or OR; R =Me, Et, Pr, Pr', or the dipole moments of a number of methyl derivatives, including MePH, and MeSiH,, have been investigated by semi-empirical M.O. calculations.201

Compounds containing P-P Bonds.-A complex containing co-ordinated P,H2 results when (r-Cp),MoH, and white phosphorus are heated in toluene.z02The formula is (r-Cp),MoP,H,, m d as P2Hz is isoelectronic with ethylene a structure similar to that of the ethylene analogue is postulated. Microwave spectra for PzH4,P2D4,and two isomeric forms of P2D,H have been analysed to give molecular parameters and dipole moments.203For the fully deuteriated compound r(P-D) is 1.414(2) and 1.417(2) A and r(P-P) is 2.2191(4) A; the dihedral angle is 74(2)", confirming the gauche conformation. Photoelectron spectroscopy is considered to be a suitable technique for detecting rotational isomerism in both diphosphines and diarsines, and probably other species containing atoms with adjacent electron pairs.204 Results are presented here for methyl and trifluoromethyl derivatives. Silylated imino-diphosphines (7) and (8) are obtained when tetra-alkyldiphosphines react with, respectively, one and two moles of azido trimethylsilane.'05 Compound (7) gives a thio-derivative, and the products of hydrolysis have been discussed. In the case of (8), small amounts of the dioxide (9) are produced. A new type of unsymmetrical diphosphine containing R,P-PR,

II

NSiMe,

(7)

R,P-PR,

It II

Me,SiN

NSiMe,

(8)

R,P-PR,

II I1

0 0 ('1)

either alkyl and alkoxy- (or aryl and aryloxy-) groups has been reported206 from the reactions shown in equations (4) and (5). Reorganization reactions

199

2 00 201

202 203 2 04

205

206

(R'O),PH+ R$PCI--+(R'0)2PPR:

(4)

RiPH+ (R20),PCl+ R;PP(OR'),

(5)

J . W. Long and J. L. Franklin, J. Arner. Chem. SOC., 1974, 96, 2320. R. Turpin, P. Dagnac, P. Castan, and D. Voigt, J . Chin1 p h y r . 1973, 70, 1625. M. S. Gordon and L. Neubauer, J. Amer. Ch&. SOC., 1974, 96, 5690. J. C. Green, M. L. H. Green, and G. E. Morris, J.C.S. Chem Conim., 1971, 212. J . R. Durig, L. A. Carreira, and J . D. Odom, J . Amer. Chem. SOC., 1974, 96, 2688. A. H. Cowley, M. J. S. Dewar, D. W. Goodman, and M. C. Padolina, J . Arner. Chern. SOC., 1974, 96, 2648. R. Appel and R. Milker, Chern. Ber., 1974, 107, 2658. V. L. Foss, Yu. A. Veits, V. V. Kudinova, A. A. Borisenko, and I. F. Lutsenko, J . Gen. Chem. (U.S.S.R.), 1973, 43, 994.

Elements of Group V

339

occur in some cases on distillation; full spectroscopic data are given for the compounds. A stable thioester of hypodiphosphorous acid (10) results when the monochloride (1 1) reacts with sodium me~al.'~'

(1 1)

(10)

Mixtures of P,F, and ethylene give 1,2-bis(difluorophosphino)ethane either o n photolysis in a quartz reactor or by heating to 300 "C in a sealed tube.'" Full spectroscopic data confirm the structure of the product. The compound displays dibasic character on treatment with diborane, with BH, groups being attached to each phosphorus atom. The crystal structure of ammonium diaminodiphosphate(Iv), one of the products obtained from the oxidation of red phosphorus, shows the presence of centrosymmetric [0,P(NH2)P0,(NH,)]2~ions.'o9 These are linked through hydrogen bonds from the cation to give a structure closely related to that of the ammonium and hydroxonium salts of [0,P(OH)P0,(OH)]2-. 2.186(4)A; P-0, 1.473(6) and Principal bond lengths are: P-P, 1.512(5) A; P-N, 1.663(5) A. Metal carbonyl complexes are reported for triphenylcyclotriphosphine Ph,P,2'0 and the polyphosphines (12) and (13).'11 Peaks associated with the ionization of the phosphorus lone-pair electrons of (13) and the analogous pentamer can be assigned in the photoelectron spectra, giving values which imply that any (p-d).rr-bonding must be relatively unimportant.212Anion F,C F,C-C=C-CF,

I t

FXC-P-P-CF, F,C-P-P-CF, I I

(12)

(13)

F,C-P-P-CF,

\

/CF3 c=c I \

F,CP,p,PCF,

I

CF3 (14)

radicals could not be generated from (13) or (MeP),, but by electrolytic reduction, radicals were obtained from (12) and ( 14).'13 E.s.r. measurements on such species were rationalized by considering that the unpaired electron was localized mainly in the C=C bond, there being little delocalization to the phosphorus atoms. M. Baudler, A. Moog, K. Glinka, and U. Kelsch, Z . Naturforsch., 1973, 28b, 363. K. W. Morse and J. G. Morse, J. Amer. Chem. SOC., 1973, 95, 8469. W. S. Sheldrick, Z . anorg. Chem., 1974, 408, 175. *lo M. Baudler and M. Bock, Angew. Chem. Internat. Edn., 1974, 13, 147. 211 A. H. Cowley and K. E. Hill, Inorg. Chem., 1974, 13, 1446. 212 A: H. Cowley, M. J. S. Dewar, D. W. Goodman, and M. C. Padolina, J . Amer. Chem. Soc., 1974, 96,3666. 213 T. C . Wallace, R. West, and A. H. Cowley, Inorg. Chem., 1974, 13, 182. '07

'08

'09

Inorganic Chemistry of the Main-group Elements

340

The polyphosphines Ph,P, and Ph,P, have been reduced electrochemically in an attempt to resolve the confusion associated with the nature of these species in In each case, the results are consistent with a simultaneous two-electron transfer to the rings followed by very rapid ring degradation. Although it is not possible to' distinguish between the solutions electrochemically, they are clearly different on the basis of u.v.-visible and 'H n.m.r. spectroscopy. Four moles of Ph,P, react with sulphur to give Ph,P,S in good yield;*I5 this compound can also be obtained either from the cyclopentaphosphine and (PhPS), or from the dipotassium salt of triphenylcyclotriphosphine and sulphur dichloride. 1.r. and "P n.m.r. data indicate the presence of a P4S ring, and this has been confirmed by a full X-ray crystal study.216The ring is puckered, with mean distances of 2.190(5) and 2.1 16(5) A for the P-P and P-S bonds, respectively, and the general features of the structure are shown in Figure 9. (Further information o n compounds containing P-P bonds can be found in refs. 259 and 260.)

C

Figure 9 The structure of (PhP),S (Reproduced from J.C.S. Dalton, 1974, 3 8 6 ) Bonds to Boron.-CND0/2 M.O. calculations point to the staggered conformation as being preferred for PH3,BH3, PF3,BH3, PH3,BF3, and PF3,BF3, in agreement with the microwave data for the second The calculated barriers to rotation and charge transfers are similar to those obtained by ab initio methods. Vibrational spectra for PX,,BC1,,2'832'9 PX3,BBr3,218and PX3,BI3;'* where X = H or D, have been assigned and normalco-ordinate analyses carried out. A comprehensive n.m.r. investigation of the boron hydride and halide addition compounds with a number of alkyl- and aryl-phosphines is reported by Rapp and Drake.220The 'H data point to a relationship between 214

215

'17

*18 '19

'*'

T. J. DuPont and J. L. Mills, Inorg. Chern., 1973, 12, 2487. M. Baudler, Th. Vakratsas, D. Koch, and K. Kipker, Z . anorg. Chern., 1974, 408, 225. H. P. Calhoun and J . Trotter, J.C.S. Dalton, 1974, 386. M.-C. Bach, F. Crasnier, J.-F. Labarre, and C. Leibovici, J. Fluorine Chern., 1973, 3, 409. J. E. Drake, J. L. Hencher, and B. Rapp, J.C.S. Dalton, 1974, 595. J. D. Odom, S. Riethmiller, J. D. Witt, and J. R. Durig, Inorg. Chern., 1974, 13, 1123. B. Rapp and J. E. Drake, Inorg. Chern., 1973, 12, 2868.

Elements of Group V 34 1 the downfield shift of the phosphorus proton(s) and the relative acidities of the boron Lewis acids, provided the base-is kept constant. There is also general consistency between the "B and 31Pshifts, upfield and downfield respectively, on formation of the P -+ B bond. Further 'H and "B n.m.r. data are available on the 1 : 1 adducts between BBr, or BI, and Me,P, Me,PhP, Me,PSe, Ph,PO, etc.22' New 1:1 borine adducts of B u : - , P F ~ ~and ~ Bu:-,PC1,,222 where n = 0-3, and Me,PCl**' have been characterized by i.r. and n.m.r. spectroscopy. Adduct formation between the boron halides and methyldichlorophosphine occurs for the chloride, bromide, and ibdide but the fluoride is a weaker Lewis acid, and no complex Further workzz5points to the non-existence of the previously claimed compounds PCl,,BF, and PC13,BC13, but there is evidence for the formation of 2MezPC1,BF,. N.m.r. data on the borine adducts of amino-phosphines such as Me,NPMe,, (Me,N),PMe, and (Et,NCH,),P show co-ordination to the phosphorus atom in the first two compounds but in the last, where the N and P atoms are separated by a methylene bridge, the nitrogen atom is the co-ordination site.226Explanation of the different behaviour is in terms of P-N multiple bonding and changed steric effects. Exchange between the complex Me3P,BMe3and an excess of Me3B, as followed by n.m.r. spectroscopy, is first-order in complex concentration, suggesting a dissociative mechanism, but a bimolecular reaction is followed for the exchange of the corresponding AlMe3 complex and excess Me,AI, in toluene (Further information on compounds containing boronphosphorus bonds can be found in refs. 208, 251, 275, 276, and 462). Bonds to Carbon.-Phosphorus(m) Compounds. The first part of a general review on the reactions of phosphorus(rI1) compounds with polyhalogen compounds has appearedzz8and deals with reactions of alkyl- and arylphosphines with the carbon tetrahalides. Photoelectron spectra have been reported for*HCPZZ9 and for PhPH2, Ph,PH, and Ph3P.230 Comparison of the latter with data for the nitrogen, arsenic, and antimony analogues implies a shift of electron density from the phenyl groups to the heavier Group V element, suggesting expansion of the valence shell with inclusion of ndorbitals in the bonding.

221

222

223

224

225

226 227

229

230

M. L. Denniston and D. R. Martin, J. Inorg. Nuclear Chem., 1974, 36, 1461. C. Jouany, G. Jugie, J.-P. Laurent, R. Schmutzler. and 0. Stelzer, J. Chim.phys., 1974, 71, 395. J. D . Odom, S. Riethmiller, and J. R. Durig, J. Inorg. Nuclear Chem., 1974, 36, 1713. R. M. Kren, M. A. Mathur, and H. H. Sisler, Inorg. Chem., 1974, 13, 174. R. T. Markham, E. A. Dietz, jun., and D. R. Martin, J. Inorg. Nuclear Chem., 1974,36,503. C. Jouany, J.-P. Laurent, and G. Jugie, J.C.S. Dalton, 1974, 1510. E. Alaluf, K. J. Alford, E. 0. Bishop, and J. D. Smith, J.C.S. Dalton, 1974, 669. H. Teichmann, 2. Chem., 1974, 14, 216. D. C. Frost, S. T. Lee, and C. A. McDowell, Chem. Phys. Letters, 1973, 23, 472. T. P. Debies and J. W. Rabalais, Inorg. Chem., 1974, 13, 308.

Inorganic Chemistry of the Main -group Elements

342

’H n.m.r. spectra for three- and four-co-ordinated phosphorus and arsenic derivatives with one to three methyl groups have been c~mpared.’~’ The shifts for the methyl protons are very similar when the compounds are three-co-ordinate but markedly different in the four-co-ordinate species; the latter is rationalized on the basis of the greater back-co-ordination to phosphorus than arsenic. Assignments are given for the i.r., Raman, and I9F n.m.r. spectra of the compounds M(C=CCF,),, where M = P, As, or Sb.232 After hydrolysis with aqueous ammonium chloride, a product formulated as PC,,3H,O is obtained from the reaction between PCl, and ethynylenedimagnesium dibromide, BrMgC=CMgBr.’,, The product from a similar reaction with GeCl, was given as HC%CGeC,,H,O. The optimum geometry of tri-t-butylphosphine has been determined by C N D 0 / 2 calc~lations,’~~ and the CNDO/S method has been extended to include second-row elements.235The results for phosphorin (15) satisfactorily explain the observed U.V. transitions, dipole moment, and ionization potentials. An X-ray structure of 1-benzylphosphole (16) points to the distance of presence of a non-planar ring with a mean P-C(ring) 1.783 A;236 the shortening of the latter over the sum of the single-bond radii is consistent with some delocalization of the phosphorus lone pair. A number of new cyclic phosphides of carboxylic acids such as (17) can be

I

CH,Ph

0

(16)

(15)

(17)

synthesized, for example, from the diacid chloride and Li,PEt,”’ while new 1,3-thiaphosphorinans (18) result when y-mercaptopropyl-phenylphosphine and either aldehydes or ketones

/““ ?-

PhP,

H2\ CH, /

\

S

/

R’ (18) M. Durand and J.-P. Laurent, J. Chim. phys., 1973, 71, 847. 232 D. H. Lemmon and J. A. Jackson, Spectrochim. Acta, 1973, 29A, 1899. 2’3 A. A. Kuznetsova, Yu. G. Podzolko, V. V. Kovalov, and Yu. A. Buslaev, Russ. J. Inorg. Chem., 1973, 18, 750. 234 M. Corosine, F. Crasnier, J.-F. Labarre, M.-C. Labarre, and C . Leibovici, J . Mol. Structure, 1974, 22, 257. 235 K.-W. Schulte and A. Schweig, Theor. Chim. Acta, 1974, 33, 19. 236 P. Coggon and A. T. McPhail, J.C.S. Dalton, 1973, 1888. ’” K. Issleib, Kr. Mohr, and H. Sonnenschein, Z . anorg. Chem., 1974, 408, 266. *” K. Issleib and H.-J. Hannig, Z . anorg. Chem., 1973, 402, 189. 231

Elements of Group V

343

A novel route to aminomethyl-phosphines involves the insertion of N-tbutylmethyleneimine into a P-H bond as shown in equation (6).239 PhPH, + CH,=NBu' + PhHPCH2NHBu' (6) Addition of two moles of diphenylvinylphosphine to PhHPCH,CH,PHPh gives two isomeric tetraphosphines Ph,PCH,CH,PPhCH,CH,PPhCH,CH,PPh,, with very different the compounds appear to be d l - and meso-forms arising from the presence of two equivalent asymmetric phosphorus atoms. This type of reaction has also been used to prepare, for the first time, polytertiary phosphines with 5, 7, 8, or 10 phosphorus atoms,241 giving compounds with formulae such as PhP[CH2CH,P(CH2CHzPPh~)z]z, P[CH2CH,P(CH,CH,PPh,)z]3,etc. King and Heckley2"' have converted similar polytertiary phosphines into the corresponding oxides and sulphides by reaction with, respectively, hydrogen peroxide and sulphur. Phosphorus (v) Compounds. The ylide Me,PCH, is the starting material for For example, addition a novel synthesis of tetramethylphosphonium of one mole of acetic acid in ether gives Me,P' OAc- while a further mole of acid yields the hydrogen diacetate anion. The analogous azide, thiocyanate, nitrate, and thiosulphate result when HN3, NH,SCN, NH4N03, or NH,&03 are used. Alcohols or phenols add similarly to R3PCH, (R = Me or Ph) but five-co-ordinate species are the products when the reaction ratio is 1:1.'""When excess alcohol is present, ionic phosphonium compounds with hydrogen-bonded anions such as (RO..-H...OR)-, [H,(OR),]-, and [H3(OR),]- result. Corresponding reactions between alkanethiols and the ylides, on the other hand, produce the salts R P +R'S- only. Pure samples of two further phosphorus ylides, Me,PhPCHi and MePh,PCH,, can be produced via the trimethylsilyl derivative^.',^ Thermal decomposition gives the corresponding methylphenylphosphine and on reaction with methanol there is evidence for a five-co-ordinate tetraorgano-alkoxyphosphorane intermediate, but the course of the reaction depends on the number of aryl substituents at phosphorus. Crystal structury a_re now available for 2,2-diethoxyvinylidenetriphenylphosphorane, Ph3P-C=C(OE t)2,246 and the salt, [Ph,P=CH-PPh,]'Br-.'"' In the latter the P-C (bridge) distances are 1.710(4)and 1.695(4)A, and the PCP angle is 128.2". Temperature-dependent 'H n.m.r. data for substituted aryl-bis(4,4'-dimethyl-2,2'-biphenylylene)phosphoranes are interpreted as showing that pseudorotation proceeds here by way of a squarepyramidal intermediate rather than by a simple Berry process.248 239 240

241

242

243 244 245

246 247 248

K. Issleib, M. Lischewski, and A. Zschunke, Z . Chem., 1974, 14, 243. R. B. King, P. R. Heckley, and J. C. Cloyd, jun., 2. Naturforsch., 1974, 29b7 574. R. B. King and J. C. Cloyd, jun., Phosphorus, 1974, 3, 213. R. B. King and P. R. Heckley, Phosphorus, 1974, 3, 209. H. Schmidbaur and H. Stiihler, 2. anorg. Chem., 1974, 405, 202. H. Schmidbaur and H. Stiihler, Chem. Ber., 1974, 107, 1420. H. Schmidbaur and M. Heimann, Z. Naturforsch., 1974, 29b, 485. H. Burzlaff. U. Voll, and H.-J. Bestmann, Chem. Ber., 1974, 107, 1949. P. J. Carol1 and D. D. Titus, Cryst. Struct. Comm., 1974, 3, 433. G. M. Whitesides, M. Eisenhut, and W. M. Bunting, J. Amer. Chem. SOC.,1974,96,5398.

Inorganic Chemistry of the Main-group Elements 344 A novel reaction leading to aryloxy- or arylthio-phosphonium salts involves treating a phosphine in the series Ph,(Me,N),-,P, where n = 0-3, with a phenol or thiophenol and carbon t e t r a ~ h l o r i d e .The ~ ~ ~products, [Ph, (MezN)3-,,P(OAr)]’, can then be isolated as the hexachloroantimonates.

Bonds to Silicon.-Trifluorosilylphosphine F,SiPH, and the corresponding arsine have been synthesized in good yields from F,SiBr and, respectively, trimethylstannyl-phosphine or -ar~ine,,~’ while an alternative route to the phosphorus compound involves the silicon mixed halide and a phosphinoaluminate, LiAl(PH4)4.251 Attempts to carry out similar reactions with F,SiBr, or FSiBr, were not successful because of disproportionation of the resulting silyl-phosphines, but with monobromomethylsilanes Me, H,-,SiBr good yields of the methylsilylphosphines Me,H,_,SiPH, with II = 0-3, could be obtained.2s52 These products are readily dimetallated with two moles of LiPEt, and mono-lithiated when LiPHMe is The former products, Me,H,-, SiPLi2, react with methyl chloride, giving P-dimethyl derivatives, but the latter are unstable and disproportionate, giving, for example, (H,Si),PLi and LiPH,. A new series of substituted silylphosphines can be obtained when mixtures of halogenosilanes and silylphosphines containing PH, groups are reorgani~ed.,~,Two possibilities are shown in equations (7) and (8) but similar reactions occur with SiBr,, SiBr,F, SiBr,F,, etc.

+ MeSiHC1, MeHSi(PH,), + SiCl,

MeHSi(PH,),

4

2MeSiHClPH2

(7)

4

MeSiHClPH, + Cl,SiPH,

(8)

It is possible to prepare trimethylsilylphosphines by abstracting chlorine atoms as MgC1, from Me,SiCl and Bu:-,PCl,, where n = 1-3.255 For each of the products, reaction with Me,GeCl or Me,SnCl leads to displacement of Me,SiCl and formation of the analogous germyl or stannyl derivatives. Exchange of the substituted phosphorus atom in Me,SiPMe, occurs on reaction with (CF,),PH to give a good yield of Me,SiP(CF,),.’56 A carbonylbridged diphosphine CO(PPh,), is the product when Me,SiPPh, reacts a t - 1 1 0 ° C with phosgene; at higher temperatures CO evolution is obSubstituted 1,3-diphosphorinans (19) or diphospholans (20) are the products resulting from reactions between alkali-metal (M) phosphides such as H. Teichmann and W. Gerhard, 2. Chem., 1974, 14, 233. R. Demuth, Z. Naturforsch., 1974, 29b, 42. G. Fritz, H. Schafer, R. Demuth, and J. Grobe, Z . anorg. Chem., 1974, 407, 287. ’” G. Fritz and H. Schafer, Z. anorg. Chem., 1974, 406, 167. 253 G . Fritz, H. Schafer, and W. Holderich, Z. anorg. Chem., 1974, 407, 266. 254 G. Fritz and H. Schafer, Z. anorg. Chem., 1974, 407, 295. 255 H. Schumann and L. Rosch, Chem. Ber., 1974, 107, 854. 256 J. E. Byrne and C. R. Russ, J. Inorg. Nuclear Chem., 1974, 36, 35. 257 H. J. Becher and E. Langer, Angew. Chem. Internat. Edn., 1973, 12, 842. 249

250

251

345

Elements of Group V Ph

Ph

CH /CHz-p

<

CH2-P

Ph

CHZ-P

Ph

MPhP(CH,),PPhM, where y1 = 2 or 3, and diorganodichlorosilanes.”” Similar ring-closure reactions occur with tin and aluminium organodichlorides. A new disilylphosphine (21) is produced by the reaction between bromine or iodine and potassium phenyl(trimethylsily1)phosphide in benzene solut i ~ n on ; ~ changing ~ ~ the solvent to THF, the reaction becomes more complex but the diphosphane (22) can be isolated. The latter is also the product from trime th ylsil yla tion of dip0tassium p henylp hosp hide .260 Me,Si

\

M e S i/pph

(21)

Me,Si

\

/SiMe3

Ph/p-p\ph

(22)

Bonds to Fluorine.-Phosphorus (111) Compounds. SCF wavefunctions for PF allow estimation of the dissociation enthalpy (4.7 eV), the dipole moment (0.6 D), and the P-F distance (1.58A), etc.,261while the emission spectra of the species produced by the action of microwave discharges on HPF, and PF, may be analysed in terms of the PF diatomic.262Experimental data for the e.s.r. parameters of the PF, and those calculated by ab initio methodP4 are in good agreement. New M.O. calculations by both a non-empirical valence-electron (NEVE)265and a self-consistent charge and configuration266method are available for PF,; the PF, molecule has also been treated by the former method.265 Results from CND0/2 calculations on F,PNCO (and also CF,NCO and H,SiNCO) are in good agreement with spectroscopic results? and a conformational analysis of F,POPF, using the same approachZ6’indicates that the preferred conformation has no symmetry elements as a result of the interplay of a number of energy terms. Vapour-phase Raman spectra have been recorded and assigned for PX, 258 259

260

261 262

263

264 265

266 267 268

K. Issleib and W. Bottcher, 2.anorg. Chem., 1974, 406, 178.

M.Baudler, M. Hallab, A. Zarkadas, and E. Tolls, Chem. Ber., 1973, 106, 3962. M.Baudler and A. Zarkadas, Chem. Ber., 1973, 106, 3970. P. A. G. O’Hare, J. Chem. Phys., 1973, 59, 3842. E. G. Skolnik and P. L. Goodfriend, J. Mol. Spectroscopy, 1974, 50, 202. A. J. Colussi, J. R. Morton, K. F. Preston, and R. W. Fessenden, J. Chem. Phys., 1974, 61, 1247. J. C. Cobb and A. Hinchlze, Chem. Phys. Letters, 1974, 24, 75. k.G. Hyde, J. B. Peel, and K. Terauds, J.C.S. Faraday 11, 1973, 69, 1563. D. A. Wensky, J. Chem. Phys., 1974, 60, 1. B. M. Rode, W. Kosmus, and E. Nachbaur, Monatsh., 1974,105, 191. G . Robinet, J.-F. Labarre, and C. Leibovici, Chem. ,Phys. Letters, 1974, 26, 203.

346 Inorganic Chemistry of the Main-group Elements (X = F, C1, or Br), AsX, (X = F, Cl, Br, or I), and SbX, (X = C1, Br, or I),"' and the changes in the PF, vibrational frequencies on passing from the free molecule to the complex Ni(PF,), have been c a l ~ u l a t e d . ~ The ' ~ positive- and negative-ion mass spectra of PF, and PF2CN as a function of electron energy have now been Major species for the nitrile are PF,CN', PFCN', PF:, and PF' and PF,CN-, PF;, CN-, and F-; among the bonddissociation energies determined is a value of S3.4k0.5 eV for D(PF2CN) . Aluminium chloride reacts with PF, under pressure, giving a 1:1 adduct to which an ethane-type structure is assigned on the basis of molecular weight and n.m.r. data.z72Alternatives involving either halogen bridges or ionic structures are considered much less likely. Reactions between PF, and metal oxides continue to attract attention. A number of transition-metal oxides can be reduced, but in some cases it is necessary to add magn e ~ i u r n . ~With ~ ' ZnO, the initial reaction is to give Zn and POF,, but subsequent steps give ZnF,, Zn,P,, and Zn(P0,)2;274both cadmium and mercury oxides also initially yield the metal, but the major product at 500 "C with the former is Cd,P,O,. Tertiary butyl and isopropyl alcohols both react with PF, in the presence of pyridine, replacing one fluorine atom.275The isopropyl compound, PF20Pri,forms a stable borane adduct but the t-butyl analogue is apparently reduced by B2H6in an unusual reaction. PF2Hundergoes methanolysis in the presence of pyridine to give the previously unknown dimethoxyphosyhine (MeO),PH, which has now been completely c h a r a c t e r i ~ e dAt . ~ ~low ~ temperatures, intermediates with the general composition HF,P,HOR or HF,P,HSR can be isolated from reactions between alcohols or thiols and the difluoride. These are unequivocally characterized by n.m.r. and i.r. data as five-co-ordinate trigonal-bipyramidal species with the two fluorine atoms in axial p o s i t i o n ~ . ~ ~ ' Microwave data for CH,OPF, and its isotopically substituted analogues point to the methyl group being cis to the fluorine atom^."^ The barrier to internal rotation is 422 f5 cal mol I , and the important molecular parameters are: r(P-F) = 1.591(6) A; LFPF = 94.8(6)"

*" 270 L71

272 271 274

275

276 277 278

r(P-0)

= 1.560(15)

r(C-0)

=

1.446(5)

A;

A;

LOPF= 102.2(10)" LCOP = 123.7(5)"

R. J. H. Clark and D. M. Rippon, J . Mol. Spectroscopy, 1974. 52, 58. S. J. Cyvin, Z. anorg. Chem., 1974, 403, 193. P. W. Harland, D. W. H. Rankin, and J. C. J. Thynne, Internat. J. Mass Spectrometry Ion Phys., 1974, 13, 395; Inorg. Chem., 1974, 13, 1442. E. R. Alton, R. G. Montemayor, and R. W. Parry, Inorg. Chem., 1974, 13, 2267. A. P. Hagen and E. A. Elphingstone, J. Inorg. Nuclear Chem., 1973, 35, 3719. M.Chaigneau and M. Santarromana, Compt. rend., 1974, 278, C , 1453. E. L. Lines and L. F. Centofanti, Inorg. Chem., 1973, 12, 2718, L.F. Centofanti, Inorg. Chem., 1974, 13, 1131. L. F. Centofanti and R. W. Parry, Inorg. Chem., 1974, 13, 1456. E. G. Codding, C. E. Jones, and R. H. Schwendeman, Inorg. Chem., 1974, 13, 178.

Elements of Group V

347

The methyl analogue MePF2 has also been s t ~ d i e d , ”giving ~ 2300 cal mol-’ as the barrier to internal rotation. Excellent yields of the difluorophosphine CF,SPF, result from treatment of PF,Br with bis(trifluoromethylthio)mercury.2s0 Low-temperature oxidation gives CF3SPOF2,and CF,SPF,Cl, and CF,SPF,Cl are the products with C1, and ClF, respectively. The direct oxidation method can be extended to the preparation of other difluorophosphoryl compounds OPF2X, where X = C1, Br, NCS, or NMe2, from the corresponding phosphorus(II1) compounds. Assignments on the basis of C, symmetry are given for vibrational data on a series of bis(trifluoromethy1)phosphines (CF,),PX, where X = H, F, C1, Br, or I.”’ Preparative methods have been devised for compounds of the type R(CaF,)PX, where X = F, C1, Br, or NMe, and R = Me, Et, But, or Ph;282the products can then be converted into the corresponding trifluorophosphoranes and phosphinic acid fluorides R(C,F,)POF. 31P and 19F n.m.r. spectra have been obtained for all the compounds. Improved synthetic methods for the mixed halides Me,NPFCl and Me,NPFBr have been reported and the new triple halide PFClBr, melting at -122 “C, has been obtained by allowing Me,NPFCl to react with HBr.283 Phosphorus (v) Compounds. A b initio LCAO-SCF calculations have been carried out for PF, and PF4H.284 The He (I) photoelectron spectrum of PF, can be assigned readily by analogy with data from a number of semiempirical M.O. ~alculations;2~~ the fifth peak shows vibrational fine structure corresponding to the symmetric stretch of the two axial fluorine atoms. No excited-state transitions were detected in a detailed examination of the Raman spectrum of PF, in the gas phase, and a value of ca. 5 kcal mol-’ is suggested as the lower limit for the barrier to pseudorotation.286It is now thought that PF, rather than PF; is the species generated by y-irradiation of NH,PF, or KPF,.287Negative-ion ion-cyclotron resonance spectra give values of the fluoride-ion affinity of a number of species, including PF, and AsF,, and the enthalpies of formation of the corresponding fluoro-anions can be estimated.288A partial acidity series is: SF, < AsF, < SiF4< BF, < PF, < BCl, < AsF, It is well known that traces of moisture or hydrogen fluoride can

’’’ E. G. Codding, R. A. Creswell, and R. H. Schwendeman, Inorg. Chern., 1974, 13, 856. G. H. Sprenger. and J. M. Shreeve, J. Fluorine Chern., 1974, 4, 201. ’” R. C. Dobbie and B. P. Straughan, J.C.S. Dalton, 1973, 2754. 282

M. Fild and T. Stankiewicz, Z. anorg. Chem., 1974, 406, 115. R. G. Montemayor and R. W. Parry, Inorg. Chem., 1973, 12, 2482. 284 J. M. Howell, J. R. Van Wazer, and A. R. Rossi, Inorg. Chern., 1974, 13, 1747. ”’ D. W. Goodman, M. J. S. Dewar, J. R. Schweiger, and A. H. Cowley, Chem. Phys. Letters, 1973, 21, 474. 286 J. D. Witt, L. A. Carreira, and J. R. Durig, J. Mol. Structure, 1973, 18, 157. 287 S. P. Mishra and M. C. R. Symons, J.C.S. Chern. Comm., 1974, 279. J. C. Haartz and D. H. McDaniel, J. Amer.-Chem. SOC., 1973, 95, 8562. 283

348

Inorganic Chemistry of the Main-group Elements

markedly influence the n.m.r. spectra observed with molecules which undergo intra- or inter-molecular fluorine exchange. This is emphasized in recent work on the PF,,OEt, system, and pretreatment with (Me,Si),NH to remove the impurities is recommended.289 The expected octahedral geometry around phosphorus in (23) is found in the crystal structure of

PFs,py,29nbut the plane of the pyridine molecule forms an angle of 40.8” with the F,PN plane. Further, the four coplanar fluorines are displaced from the remaining fluorine, probably as a result of the smaller repulsion by the long P-N bond. Vapour-pressure and n.m.r. methods have been used to give data on the complexation of PF, and BF, by solutions containing TaF, and NbF;.’”’ Three new hydrides, CF,PF,H (24), (CF,),PF,H, and (CF,),PH,, can be isolated from vapour-phase reactions between Me,SiH and (CF,),PF,-, with n = 1-3;”’ in addition, CF,PF,H, could be detected by n.m.r. spectroscopy. In view of the stability of these species, it is considered likely that F

H..j

F

F

other di-, and possibly higher, hydrides of phosphorus(v) may be obtainfor CF,PF,H (24) and PF,H, (25) are in able. Dynamical ‘H n.m.r. agreement with fluxional trigonal-bipyramidal structures and yield values of AHSand AG’ for rearrangement of 8.8 and 6.3 kcal mol-’, respectively, for (24) and 14.2 and 10.2 kcal mol-’ for (25). Low-temperature n.m.r. studies on similar trifluoromethylphosphoranes can be interpreted to yield a partial ‘apicophilicity’ that is, an order of the tendency of a group to occupy an apical position in a trigonal-bipyramidal phosphorus(v) structure. The series F, Cl>CF,>OSiMe,, OMe, SMe, NMe,, H, Me, which rationalizes all the present data, is based on inductive rather than n bonding or steric effects. 289 29 1

292 293 2y4

J. A. Gibson, D. G. Ibbott, and A. F. Janzen, Canad. J. Chem., 1973, 51, 3203. W. S. Sheldrick, J.C.S. Dalton, 1974, 1402. S. Brownstein, J. Inorg. Nuclear Chem., 1973, 35, 3567, 3575. J. W. Gilje, R. W. Braun, and A. H. Cowley, J.C.S. Chem. Comm., 1973, 813. J. W. Gilje, R. W. Braun, and A. H. Cowley, J.C.S. Chem. Comm., 1974, 15. R. G. Cavell, D. D. Poulin, K. I. The, and A. J. Tomlinson, J.C.S. Chem. Comm., 1974, 19.

349

Elements of Group V

The first compounds containing an intramolecular N + P co-ordinate bond (26) are formed when substituted fluorophosphoranes R'PF, and 8trimethylsiloxyquinolines react.295On decreasing the electronegativity of the F

'F

R' substituent, the N + P bond strength also decreases, and with Me2PF, the bond does not form. A single-crystal determination was carried out for (26) where R' = F and R2=Me. A detailed structure is also available for 2me thyl-5 -( tetrafluorophosphorany1)pyrrole, which has trigonal-bipyramidal The pyrrole ring occupies an equatorial position but is oriented in the axial plane, qnsistent with the previous 19F n.m.r. data. The P-C bond (1.740 A) is short, implying some interaction between the 7r-orbitals of pyrrole and the phosphorus atom. Interesting 19Fn.m.r. results have been observed in the low-temperature The spectra of (27), where R2= CHMeEt, CHMePr, CHMeCH,Cl, two apical fluorine atoms become non-equivalent, a situation attributed not to a hindered rotation of the alkoxy-group but to asymmetry in the alkoxy-groups. The Berry pseudorotation mechanism, on the other hand, n.m.r. spectra can be used to explain the temperature dependence of the of Me,NPF,, ClPF,, and MePF,.29sActivation free energies can be obtained and the rate of pseudorotation in XPF, compounds is shown to increase in the order MezN< SR, H < C1< CH, < F. New substituted fluorophosphoranes have been prepared by reactions with, respectively, Li[N=C(CF,),]299 and Me,SiN=S=NSiMe,.300 Monoand di-substituted compounds, RPF,N=C(CF,), and RPF,=NC(CF,),N=C(CF,),, are the products of reactions of RPF, with the former, while derivatives of a bicyclic phosphorus trisulphur pentanitride system, PS3N5F2and PhPS3N5F,result when PF, or PhPF, react with the latter. Two new routes to organofluorophosphoranes have been announced. In the a phosphine or chlorophosphine reacts with carbon tetrachloride and an HF donor such as phenylcarbamoyl fluoride; compounds in the

"' K.-P. John, R. Schmutzler, and W. S. Sheldrick, J.C.S. Dalton, 1974, 1841. W. S. Sheldrick, J.C.S. Dalton, 1973, 2301. D. U. Robert, D. J. Costa, and J. G. Riess, J.C.S. Chem. Comm., 1973, 745. 298 M. Eisenhut, H. L. Mitchell, D. D. Traficante, R. J. Kaufman, J. M. Deutch, and G. M. Whitesides, J. Amer. Chem. SOC., 1974, 96,5385. z99 J. A. Gibson and R. Schmutzler, Z . Naturforsch., 1974, 29b, 441. 300 R. Appel, I. Ruppert, R. Milker, and V. Bastian, Chem. Ber., 1974, 107, 380. 301 R. Appel and A. Gilak, Chem. Ber., 1974, 107, 2169. 296

297

350 Inorganic Chemistry of the Main-group Elements series RJPF2, RiR'PF,, R2PF3, and RPF.,, can be readily obtained. The second method302 gives difluorides and involves reaction between a phosphorus(I1r) compound and preferably trifluoromethyl hypofluorite, though other trifluoromethyl compounds can be used. A perfluoropinacolyltrifluorophosphorane (28 ; R = F), having interesting fluxional characteristics, has been synthesized from the silyl derivative [28; R = (Me3Si),N];303the latter, on pyrolysis, gives a new diazadiphosphetidine. F

R---P

i

/ d F

P o

(28) R = F or (Me,NSi),N

Vibrational data for BuiPF, are consistent with C,symmetry, and a trigonal-bipyramidal structure is strongly preferred, in agreement with n.m.r. Comparison of magneto-optical results for the alkylfluorophosphoranes R,PFS ,,, where R = E t , Pr", or Bun and n = 1-3, with data for phosphorus(Ir1) analogues points to a slightly greater electronegativity for a neutral phosphorus(v) atom and t.he presence of r-character in the P-F bonds in RPF, and PF,.'"'

Oxyphosphorus(v) Compounds. Ab initio SCF-LCAO calculations for OPF, and SPF, suggest that the P=S bond is weaker and less polar, but it has a higher .rr-character than the P=O bond.306N.m.r. measurements on OPF, in a nematic appear to suggest that the FPF angle deviates from that found by electron diffraction; the molecule could be genuinely distorted or this result may be a consequence of large anisotropies in the indirect couplings. Improved preparative methods are reported for XPF,(NCO), X = 0 or S, using the corresponding chloride and silver cyanate at low ternperat~re;~'" the oxygen compound gives the expected carbamates and thiocarbamates on treatment with, respectively, alcohols and thiols. Equilibrium constants for the exchange of fluorine and chlorine in methyl-phosphonyl, -thiophosphonyl, and -selenophosphonyl centres3" and "I2

"I3 304 'OS

306 307 7"R

309 31*

N. J. De'ath, D. Z . Denney, D. D. Denney, and C. D. Hall, Phosphorus, 1974, 3, 205. J. A. Gibson and G.-V. Roschenthaler, J.C.S. Chem. Comm., 1974, 694. R. R. Holmes, G. T. Fey, and R. H. Larkin, Inorg. Chem., 1973, 12, 2225. M. Hausard, M.-C. Labarre, and D. Voigt, J . Fluorine Chem., 1973, 3, 375. A. Serafini and J.-F. Labarre, Chem. Phys. Letters, 1974, 27, 430. J. Bulthuis and C . A. de Lange, J . M a p . Resonance, 1974, 14, 13. P. K . Bhattacharyya and B. C. Dailey, Mol. Phys., 1974, 28, 209. S. R. O'Neill and J. M. Shreeve, J. Fluorine Chem., 1973, 3, 361. J. G. Riess, J.-C. Elkaim, and A. Thoumas, Phosphorus, 1973: 3, 103.

Elements of Group V 35 1 for fluorine, chlorine, and bromine exchange in phosphoryl, methylphosphonyl, and dimethylphosphinyl have been evaluated from n.m.r. data. (See also ref. 467). In the first set of experiments the relative amounts of MeP(X)FCl are less than those predicted on the basis of random scrambling, and there is a distinct preference for fluorine to be attached to the phosphorus carrying the most electronegative Group VI element. In the latter systems, fluorine-chlorine exchange is slower than that involving chlorine and bromine atoms, and while the latter systems tend to give a random distribution of halogens, there is again preferential accumulation of fluorine atoms at the MeP(0) centre. During an investigation of the chemistry of ally1 difluorophosphite, a number of complexes containing the difluorophosphonate group, e.g. [Pt(PF20)4]2-and fPd(PF20)4]2-,were isolated.,12 Spin-spin coupling constants for a number of phosphonic acid difluorides RP(O)F, have been evaluated from 'H_("P} and 'H419F} double-resonance experirnenk3l3Force-constant calculations using a simplified valence force field are reported for the compounds XPF,OMe and XPF(OMe),, where X = 0 or S."'

Bonds to Chlorine.-Phosphorus (111) Compounds. New 31Pn.m.r. parameters have been reported for the two mixed halides PClI, (6 = -21 1.4 p.p.m.) and PClJ (6 = -224.9 p.p.m. from phosphoric acid), which result from data for the other phosphorus(II1) exchange reactions of PCl, and mixed halides have also been confirmed. The results of an extensive programme of work using d.t.a. methods show that PCl, and the Group I and I1 chlorides interact only slightly, but continuous solutions are formed with WC16, SbC15,TeCl,, SeCl,, and FeC13.3'" Preparative methods and reactions of methyldichlorophosphine and dimethylchlorophosphine are surveyed in a recent review.317Acetate groups replace the chlorine atoms in R'PCl, in a stepwise manner on reaction with acetic anhydride, according to "P n.m.r. evidence, but it is not possible to isolate the products as they polymerize even on gentle heating.318However, in the presence of a-chloro-ethers such as CH3CHC10R2it is possible to isolate compounds with the formulae ClR1P(0)CH(ORZ)CH3and [CH3CH(OR*)PR'(=O)],O. 311

312 313

314

315

316

317 318

J. G. Riess, J.-C. Elkaim, and S. C. Pace, Inorg. Chem., 1973, 12, 2874. J. Grosse and R. Schmutzler, Z. Naturforsch., 1973, 28b, 515. V. I. Zakharov, Yu. V. Belov, B. I. Ionin, and A. A. Petrov, Doklady Chem., 1973, 209, 329. D. Kottgen, H. Stoll, R. Pantzer, and J. Goubeau, Z . anorg. Chem., 1974, 405, 275. K. B. Dillon, T. C . Waddington, and D. Younger, Inorg. Nuclear Chem. Letters, 1974, 10, 777. N. D. Chikanov, Russ. J . Inorg. Chem., 1973, 18, 1065. H. Staendeke and H.-J. Kleiner, Angew. Chem. Internat. Edn., 1973, 12, 877. M. B. Gazizov, D. B. Sultanova, A. I. Razumov, L. P. Ostanina, T. V. Zykova, and R. A. Salakhutdinov, J . Gen. Chem. (U.S.S.R.), 1973, 43, 2152.

352 Inorganic Chemistry of the Main -group Elements The reaction of trifluoroacetic acid with PhPCl,”’ and Ph,PC1320follows different paths. With the former, the product is the anhydride [PhCF,P(0)12 (29), 0 while the latter gives the trifluoroacetate Ph,POCOCF, (30) Hydrolysis of (29) with aqueous sodium carbonate gives the sodium salt of trifluoromethylphosphinic acid, from which the free acid can be isolated by i~n-exchange.~”Rearrangement and condensation occur when (30) is heated to 100 “C, and two compounds, Ph,P(O)COCF, and Ph,P(O)CF,, can be isolated. At higher temperatures further reaction occurs, and the product is Ph,P(O)OP(CF,),Ph,.’~” Recent reactions show that dimethylphosphine oxide, Me,P(O)H, is obtained in good yields when Me,PCl is treated with either concentrated hydrochloric acid or

Phosphorus(v) Compounds. New data on the enthalpy of formation of PCl, (-443.8 kJ mol-’) have been used to obtain a ‘best’ value for the enthalpy of formation of aqueous phosphoric acid (- 1295.8 kJ rn01-~).~~* Equatorial and axial chlorine atoms can be distinguished in the - ‘ T l n.q.r. spectra of PC15, PhPCl,, Ph2PC13,etc.,” Complexes containing the mixed phosphorus(v) cations PCl,Br’, PCl,Br:, and PClBr: have been described, and the Raman spectra of the solids can be similar data for compounds containing the PBr: and PCl; ions are also included. Characteristic shifts in some of the fundamentals are observed which can be ascribed to the type of counter-anion. A formula has now been suggested for the well-known mixed halide PzCI9Br,which results from the oxidation of PC1, by bromine in arsenic trichloride Using vibrational correlations and 31Pn.m.r. data, both PCI: and PC1,Br’ cations are suggested to be present, in addition to PCli, and the data are in favour of the formulation tiPCla, 2PCl,Br‘, 4PC1;, 4Br-. The 1:1 : 1 complex formed between butyl vinyl ether, PC15, and POCl, has been investigated and a structure Treatment of the PC1,methyl vinyl ketone complex with sulphur dioxide gives C1,P(0)OCMe=CHCH2C1,327while similar reactions between PCl,, alkyl-l,2dichlorovinyl ethers, and SO, yield substituted phosphonic dichlorides ROCCl=CClP(0)Cl,.3~s Analogous thiophosphonic dichlorides result when the initial complex is decomposed with H,S in place of SO,. Alkyl acetates P. Sartori and R. Hochleitner, Z. anorg. Chern., 1974, 404, 161. P. Sartori and R. Hochleitner, 2. anorg. Chern., 1974, 404, 164. 3 2 1 H.-J. Kleiner, Annalen, 1974, 751. R. H. Schumm, E. J. Prosen, and D. D. Wagman, J . Res. Naf. Bur. Stand., Sect. A, 1974, 78, 375. m I. P. Biryukov and A. Ya. Deich, J. Gen. Chem. (U.S.S.R.), 1973, 43, 1918. 124 A. Finch, P. N. Gates, F. J. Ryan, and F. F. Bentley, J.C.S. Dalton, 1973, 1863. 125 F. F. Bentley, A. Finch, P. N. Gates, F. J. Ryan, and K. B. Dillon, J. Inorg. Nuclear Chern., 1974, 36, 457. ”‘ S. V. Fridland and Yu. K. Malkov, 1. Gen. Chem. (U.S.S.R.), 1973, 43, 2161. ‘” L. A. Bashirova, A. I. Razumov, T. V. Zykova, and R. A. Salakhutdinov, J . Gen. Chem. (U.S.S.R.), 1974, 44, 676. V. M. Ismailov, V. V. Moskva, T. A. Babaeva, A. I. Razumov, Sh. T. Akhmedov, T. V. Zykova, and R. A. Salakhutdinov, J. Gen. Chem. (U.S.S.R.), 1973, 43, 1004. ’Iy

”(’

”’

”’

Elements of Group V 353 are known to be phosphorylated by a large excess of PCl, to give dichloro(dichlorophosphiny1)acetyl chloride, Cl,P(O)CCl,COCl, but two isomeric products (31) and (32) result if the PC1, ratio is lower.329 //”

No

CI,P

\

C1,P

/OEt

H /c=c\c,

H

(31)

7’

\

/c=c\

OEt

(32)

Structure (33) has been assigned to the product obtained when PCI, reacts with the sodium salt of methane tricarbonitrile, NaC(CN),; similar reactions occur when the PC1, is replaced by Ph,PCI5-,, where n = 1 or 3.330 However, if the silver salt of the nitrile is used, a cyclic compound (34) is obtained in addition to (33). Chlorine elimination occurs when N-l-cyanoalkyl-P-phenylphosphonimidic chlorides are prepared according to equac1 r (

’

NC\C/N=Pc*3 NC C ‘I

I

N

Cl,

Ph

C1

(36)

(35)

tion (9).”’ The product for n = 1, on treatment with hydrogen chloride, gives the 1,3,2-diazaphospholium chloride (35), but with triethylamine the tricyclic compound (36) is the product. NCCR,NCl, + Ph,PCl,-, + 2C1, + NCCR,N=PPh, Cl3-,

(9)

n=lor2 329

330

331

V. M. Ismailov, T. V. Zykova, V. V. Moskva, S. A. Novruzov, A. I. Razumov, Sh. T. Akhmedov, and R. A. Salakhutdinov, J . Gen. Chem. (U.S.S.R.), 1973, 43, 1237. V. P. Kukhar’, N. G. Pavlenko, and A. V. Kirsanov, J . Gen. Chem. (U.S.S.R.), 1973, 43, 1883. I. M. Kosinskaya, A. M. Pinchuk, V. I. Shevchenko, and G. K. Bespal’ko, J . Gen. Chem. (U.S.S.R.), 1973, 43, 1890.

354 Inorganic Chemistry of the Main-group Elements ”P n.m.r. and 35Cln.q.r. data have been reported for a number of solid compounds, including Ph,PCl’ PCl;, the bis(2,4,6-collidinium) salt (C,H,,N),PCl,, and the tropylium compound C14H,4PC1,.332 All show 31P n.m.r. signals associated with the PC1; ion, and the latter two compounds must therefore be formulated as containing chloride ion also. New reactions between chloro-phenyl-phosphonium salts [Ph4-,PC1,]+ SbCI,, where n = 1-3, and sodium azide to give the corresponding azidophosphonium salts have been Oxyphosphorus(v) Compounds. Raman spectra of OPX, (X = C1 or F) and SPCl, in the gas phase have been measured and analysed to give values of the Coriolis constants.334Anisotropic e.s.r. studies on POClj have been interpreted in terms of a trigonal-bipyramidal structure with C, symmet~y.~~’ Silica containing phosphorus(v) can be prepared readily according to recent Russian by allowing gaseous POCI, to interact with silica gel. Chemisorption occurs, forming units such as (37); with higher POCI, concentrations there is both an increase in phosphorus incorporation and /

/o-sii\

/

O=P-0-Si-

\

/

‘

/0-Si- /

\

(37)

O=P-Si/

/

\ ‘

\Si-/

\

(38)

the formation of chlorine-containing groups (38). The problem of the existence of polyphosphoryl chlorides has been partially resolved by experiments o n equilibrated mixtures of P,O, in POCI, by van Wazer and his ~ o - w o r k e r s .31P ~ ~ ~n.m.r. data point to the existence of straight-chain molecules belonging to the series P,OZnlCln+Z, where n = 1-5, and cyclic species with the formula P,O3,,Cln, in particular that with n = 4. N.m.r. evidence is also available for the presence of the branching groups in compounds such as (39) and (40). (See also ref. 468). Two papers discuss reactions in which P,0,C14 serves as a source of the dichlorophosphate ion. With VOCl,, for example, the product obtained from a reaction in phosphoryl chloride has the formula Cl,VO(O,PCI,),POCI, and the PO,CI, unit acts as a bidentate ligand.”8 With VCI,, on the

’” K .

B. Dillon, R. J. Lynch, R. N. Reeve, and T. C , Waddington, J. Inorg. Nuclear Chem., 1974, 36, 815. ’” W. Buder and A. Schmidt, Chem. Ber., 1973, 106, 3812. 334 R. J. H. Clark and D. M. Rippon, Mol. Phys., 1974, 28, 305. -m T. Gillbro and F. Williams, J . Amer. Chem. SOC., 1974, 96, 5032. 336 A . N. Volkova, A. A. Malygin, S. I. Kol’tsov, and V. B. Aleskovskii, J . Gen. Chem. (U.S.S.R.),1973, 43, 723. 337 W. E. Morgan, T. Glonek, and J. R. Van Wazer, Inorg. Chem., 1974, 13, 1832. 338 A . F. Shihada and K. Dehnicke, Z . Naturforsch., 1973, 28b, 268.

Elements of Group V

355

+ /c1

0

\:;;:/

-0

o=P-o-P-o-P=o

F1/

\O+ 0-P-0

2

other hand, the group behaves as a bridge, and the product is a polymer (4 1). Similar reactions occur between P,O,Cl, and chlorotrimethyl-stannane and -pl~mbane,',~ but here single O,PCl2 bridges (42) are suggested on the basis of i.r. and Mossbauer data. A doubly bridged system (43) appears to

c1, O-M-

-0-M-0

/ \Me

/ \Me Me

Me

Cl * (42) M

= Sn

or Pb

(43)

be formed in the polymeric Me2Sn(O2PC1,),obtained from Me,SnCl,. (See also refs. 481-490). In P(O)Cl,NCO, the P=O and NCO groups occupy trans positions according to an electron-diffraction inve~tigation.~~' The P-Cl bond [2.006(5) A] is slightly longer than in POCl,; other structural parameters are: r(C=O) = 1.221(15) A; LOPN = 113.8(10)" r(N=C) = 1.161(15) A; L P N C = 120.0(15)" r(P=N) = 1.684(10) A; L O P C l = 116.0(5)" r(P=O)= 1.455(10) A; LOPN= 113.8(10)" Normal vibrational modes have also been calculated for the 339 340 341

K. Dehnicke, R. Schmitt, A. F. Shihada, and J. Pebler, Z . anorg. Chem., 1974, 404, 249. V. A. Naumov, V. N. Semashko, and L. F. Shatrukov, Doklady Chem., 1973, 209, 188. Yu. P. Egorov, A. A. Kisilenko, and V. A. Shokoi, J . Struct. Chem. (U.S.S.R.), 1973,14,216.

356

Inorganic Chemistry of the Main-group Elements

Aminolysis of POCI, with N-methyl- and N-ethyl-aniline has been reexamined to show that, contrary to earlier reports, the products are (PhRN)2(PhNH)P0,where R = Me or Et.342Improved syntheses and definitive physical data have been given for a number of alkoxymethyl-phosphonic and -phosphonothioic derivatives, including ROCH,P(X)CI, and ROCH2P(X)C1(OEt), where X = 0 or S.343 Dibenzylamine substitution and alcoholysis compete in reactions of The PhP(X)CI,, where X = 0 or S, in stabilized chloroform as a oxy-compound gives both PhPO[N(CH,Ph),],OEt and PhPO(OEt),, but when the stabilizer is removed the products are PhPOC1[N(CH,Ph)2] and the anhydride (44). Reactions of the thio-derivative are similar, but two (PhCH,)+4

N\(CH,Ph),

I

\

Ph-P 0/ / \ O / y P h 0

forms, probably the d l - and rneso-forms, of the anhydride corresponding to (44) can be isolated. A further difference with the sulphur compound is the derivative PhPSformation of a mixed benzylamine-dibenzylamine [N(CH,Ph),],(NHCH,Ph); loss of an alkyl group from a secondary amine under similar conditions was noted above.342Two new phosphorodichloridates ROPOCl,, where R = o -biphenylyl or p-cumenylphenyl, have been prepared from phosphoryl chloride and the appropriate phen01;~"' the analogous thiophosphoryl derivatives can also be obtained. Further reactions in which the chlorines are replaced by OH, OR, NR:, NHNH,, etc. groups have been described. Re-examination of the formation of .the alkyl esters of trans -1 -chlorophosphetan 1-oxide (45; X=C1) points to the production of both cis- and

Me2

(45) X = CI or Br

342

A. P. Marchenko, A. M. Pinchuk, and N. G. Feshchenko, J. Gen. Chem. (U.S.S.R.), 1973, 43, 1887.

343 344

345

D. W. Grisley, jun. and K. Szabo, J. Chem. and Eng. Data, 1974, 19, 175. J. D. Healy, R. A. Shaw, B. C. Smith, C. P. Thakur, and M. Woods, J.C.S. Dalton, 1974, 1286. R. J. W. Cremlyn, J. David, and N. Kishore, Austral. J. Chem., 1974, 27, 1065.

357

Elements of Group V

trans -forms, with the latter pred~minating.~"~ Aryl alcohols, with the exception of phenol, on the other hand gave only the trans-isomer, and possible reasons for this behaviour have been discussed. Compound (45) reacts with NaSR (R=Me, Et, Bu, Pr, Ph, or PhCHJ and the corresponding thioesters can be ~btained.~"' Their detailed n.m.r. and mass spectral behaviour have been reported and compared with information for other phosphetan 1oxide derivatives; an important observation is that in the benzylthioderivative, cis- and trans-methyl groups can be distinguished (see also ref. 35 1). Bonds to Bromine or Iodine.-Two modifications of PBr, are suggested as being present in the solid phase from Raman spectral measurements over a temperature range.348One is said to have an ethane-like structure, with a very weak P-P bond, while the other is very similar to SbCl,. Reactions in the system PBr3-AlBr,-C,H4 lead to BrCH,CH,PBr,, tetrabromodiphosphine, and an AlBr, complex of tribromo-bis(2-bromoethy1)phosphoraneas final products, and a mechanism has now been Boron tribromide and PBr, interact at 150°C to give PBr; BBr;, which was identified by Raman ~pectroscopy.'~~ Reactions of the newly prepared phosphetan bromide (45; X = Br) with nucleophiles are faster than with the corresponding chloride, but on hydrolysis at room temperature both halides give the acid C8H,,P(0)OH.3s1Reaction at higher temperatures gives the anhydride C,HI,P(0)OP(O)C,H,,, which is resistant to further hydrolysis. (See also refs. 346 and 347). Direct replacement of one or two iodine atoms in PI, by organic groups is reported for the first time.352The successful reactions involved either one or two moles of 4-(trimethylsilyl)morpholine,giving (46; n = 1 or 2); even with an excess of the reagent it was not possible to replace the third iodine.

(46)

Bonds to Nitrogen.-Phosphorus (111) Compounds. From ab initio M.O. calculations on H,NPH, the barrier to pyramidal inversion at phosphorus can be shown to be higher than that in phosphine."' This is compatible with 346

347

349 350 351 352

3s3

J. Emsley, T. B. Middleton, and J. K. Williams, J.C.S. Dalton, 1974, 633. R. E. Ardrey, J. Emsley, A . J. B. Robertson, and J. K. Williams, J.C.S. Dalton, 1973, 2641. A. T. Kozulin, A. V. Gogolev, V. I. Karmanov, and V. A. Murtsovkin, Optics and Spectroscopy, 1973, 34, 708. R. I. Pyrkin, Ya. A. Levin, and E. I. Gol'dfarb, J. Gen. Chem. (U.S.S.R.), 1973,43, 1690. M.-C. Deneufeglise, P. Dhamelincourt, and M. Migeon, Cornpt. rend., 1974, 278, C, 17. J. Emsley, T. B. Middleton, and J. K. Williams, J.C.S. Dalton, 1973, 2701. A. M. Pinchuk, Zh. K. Gorbatenko, and N. G. Feshchenko, J. Gen. Chem. (U.S.S.R.), 1973, 43, 1839. I. G. Csizmadia, A. H. Cowley, M. W. Taylor, and S. Wolfe, J.C.S. Chem. Cornm., 1974, 432.

Inorganic Chemistry of the Main-group Elements

358

the view that in such systems the barrier is determined principally by the electronegativity difference of the bonded atoms. C N D 0 / 2 calculations are reported for H,NPF,,354 Me2NPF,,354P(NH2)3,355and XP(NH,),,”’ where X = O,S, or BH,. The results suggest that phosphorus 3d orbitals play an important part for the latter compounds when X = 0 or S but that there is little m-back-bonding in the P-B bond. Steric effects and lone pair-lone pair repulsions appear to the most important contributors to the barrier to rotation about the P-N bond in the aminophosphines Me,NP(CF,),, Me,NPCI(CF,), and Me,NPC12.356 These conclusions are based on the results of recent lone-pair ionization-potential data obtained from photoelectron spectroscopy. The position of the P-N stretching mode in phosphorus(rr1) compounds varies between 790 and lOlOcm-’, depending mainly on the extent of ~ - b o n d i n g ; ~the ~ ’ relative influences of substituents on phosphorus and nitrogen on this mode have been discussed. The N-H frequency in R’R’PNHR’ compounds is also affected by P-N ~ - b o n d i n g Increasing .~~~ electronegativity of the R’ and R2 substituents promotes r-bonding, which leads to a decrease in the stretching frequency. An alternative route to the interesting two-co-ordinate phosphorus(ii1) Contrary to compound (47) has been devised and follows equation the earlier report, the product appears to be stable at room temperature in daylight for long periods. O n reaction with Me,SiN,, compound (47) gives (Me,Si),NLi

+ PX, 3 (Me,Si),NPX

+

(Me,Si),NP=NSiMe,

X=Clor Br Me,Si

\

N-P

Me,Si

HNSiMe3

Me S’

//

i*\

Me,Si (48)

( 10)

(37)

/N-p\

NSiMe,

NSiMe,

(49)

an intermediate (Me3Si),NP(NSiMe3)Me,SiN3, to which is assigned structure ( 3 8 ) , and the final product is the three-co-ordinate phosphorus(v) species (49).35ya*b. In this connection, it is significant that there is now stereochernical evidence for the formation of a monomeric metaphosphonimidate OP(OR’)=NR2 from experiments on the photolysis of the phosphetan oxide (45;X = N3).360 M.-C. Bach, C. Brian, F. Crasnier, J.-F. Labarre, C . Leibovici, and A. Dargelos, J. Mol. Structure, 1973, 17, 23. R. Derschner, F. Choplin, and G. Kaufmann, J. Mol. Structure, 1974, 22, 421. 356 A. H. Cowley, M. J. S. Dewar, J. W. Gilje, D. W. Goodman, and J. R. Schweiger, J.C.S. Chem. Comm., 1974, 340. 157 R. Mathis, L. Lafaille, and R. Burgada, Spectrochirn. Acta, 1974, 30A, 357. ’” N. Ayed, R. Mathis, R. Burgada, and F. Mathis, Compt. rend., 1974, 278, C, 1085. 359 (a) 0. J . Scherer and N. Kuhn, Chem. Ber., 1974, 107, 2123; ( b ) E. Niecke and W. Flick, Angew. Chem. Internat. Edn., 1974, 13, 134. 360 J. Wiseman and F. H. Westheimer, J . Amer. Chem. SOC., 1974, 96, 4262. 3s4

35s

359

Elements of Group V

An unusual ionic structure, [(Me2N),P~A1C1;, is assigned to the 1:l adduct of aluminium chloride and bis(dimethylamino)chlorophosphine.361 The phosphorus atom in the cation is clearly shown to be agqin two-coordinate and to be involved in p,,-p,, bonding to nitrogen. Reactions of tetra-alkylphosphorodiamidous acids (R:N),P(O)H with Grignard reagents to give magnesium salts (R:N)2POMgX,362and with sulphur in the presence of secondary amines to give substituted ammonium phosphorodiamidothioates [R',NH21+[(R:N)2POS]-,363 have been reported. The alkyl esters of such species, e.g. (Me,N),POR, are valuable in the New cyclic preparation of aa -dichloro-esters and trichl~romethylalkanes.~~~ phosphoramidates, e.g. (50) and (51), prepared by a number of different

(SO)

methods, contain geometrical isomers according to 'H and 31Pn.m.r. data.365 Heptamethyldisilazane reacts with (R'O),PCl or R'OPCl, to give, respectively, the new silylamidophosphites (R'O),PNMeSiMe, and R'OP(NMeA similar reaction occurs between hexamethyldisilazane and the former, giving (R'0)2PNHSiMe3, which spectroscopic results show is in a temperature-dependent tautomeric equilibrium with the form (R'O),HP=NSiM e ?. Methyl iodide and the cage molecule P,(NMe), react by attaching one methyl group to a phosphorus atom, generating a cationic specie^.^^" X-Ray data show that P-N distances involving this phosphorus atom are significantly shorter (1.65 I$) and the NPN angles are significantly larger (lo?) than those at the other phosphorus atoms (1.71 A and 101", respectively). A similar cage compound, P4S4(NMe)6,has also been examined crystallograp h i ~ a l l y . ~ ~ ' ~ The bicyclic diphosphine (52), o n treatment with phosphorus(II1) halides, breaks down via a monocyclic intermediate (53) to N"-bis(diha1ogenophosphin0)dimethylhydrazine (54) as shown in equation (1l).'" Iminogroups can be incorporated at each phosphorus atom of compound (52) by M. G . Thomas, R. W. Kopp, C. W. Schultz, and R. W. Parry, J . Amer. Chem. Soc., 1974,%, 2646. 362 E. E. Nifant'ev and I. V. Shilov, J. Gen. Chem. (U.S.S.R.), 1973, 43, 2633. 363 E. E. Nifant'ev and I. V. Shilov, J. Gen. Chem. (U.S.S.R.),1973, 43, 2636. 364 J. H. Hargis and W. D. Alley, J. Amer. Chem. SOC., 1974, 96,5927. 365 M. A . Pudovik and A. N. Pudovik, J. Gen. Chem. (U.S.S.R.), 1973, 43, 2135, 2138. H. Binder and R. Fischer, Chem. Ber., 1974,107,205. 367 (a)G. W. Hunt and A. W. Cordes, Inorg. Chem., 1974,13,1688; ( b )Inorg. NuclearChem.Letters, 1974, 10, 637. 368 H. Noth and R. Ullmann, Chem. Ber., 1974, 107, 1019. 361

360

Inorganic Chemistry of the Main- group Elements Me Me N-N

Me Me Me

/Me P-N-N-P-

\Me

M

A

Me/

\

/N-N\ XP

/Me

/N-N\

X2P

\ MN-N eMe/PX

(11)

PX,

N-N (52)

(53)

(54)

reaction with either phenyl azide or diphenylphosphinyl a ~ i d e A . ~full ~~ X-ray structure determination is available for ( 5 3 , showing double-bond character in both the P-C (1.702 A) and P-N (1.676 A)

H (55)

Phosphorus (v) Compounds. A b initio M.O. calculations for K P N H , indicate that in the preferred conformation the nitrogen lone pair lies in the A general method for equatorial plane of the phosphorane preparing amine-substituted fluorophosphoranes involves the action of NNdisubstituted amino-trimethylsilanes RiNSiMe, with PF, or its organo-derivatives R’PF, and RgPF3.372If, on the other hand, N-substituted hexamethyldisilazanes are used, the products are diazadiphosphetidines (56) with PF, or R’PF, [see equation (12)] but monomeric phosphine imides 2PhPF,

+

2(Me3Si),NEt

--+

4Me3SiF

+

PhF,P-NEt

I I

(12)

E tN-PFZP h

such as EtN=PFPh, with disubstituted fluorophosphoranes. Structures have been assigned to all the products o n the basis of detailed n.m.r. studies. The reaction between PC1, and aniline and substituted anilines has been investigated to determine the factors influencing the tendency of the monomeric imide CI,P=NAr to dimerize to the corresponding diazadiphoshet ti dine."^ A major factor appears to be the basicity of the respective aniline. PhPCI, and Ph,PCl, react with sulphamic acid in acetonitrile in a manner analogous to that of PCI,, giving the related products Ph,PCI,-,=NSO,CI, where n = 1 or 3.374 3h9 370

371

372

374

M. Bermann and J. R. Van Wazer, Inorg. Chem., 1974, 13, 737. V. G. Andrianov, Yu. T. Struchkov, N. I. Shvetsov-Shilovskii, N. P. Ignatova, R. G. Bobkova, and N. N. Mel’nikov, DokIady Chem., 1973, 211, 631. J. M. Howell, Chem. Phys. Letters, 1974, 25, 51. R. Schmutzler, J.C.S. Dalton, 1973, 2687. H. A . Klein and H. P. Latscha, Z . anorg. Chem., 1974, 406,214. D. E. Arrington, Synth. React. Inorg. Metal-Org. Chem., 1974, 4, 107.

Elements of Group V

361

New silylated imino-phosphoranes, e.g. Ph,P(=NSiMe,)(CH,),P(=NSiMe,)Ph, (where n = 1-3), are the products of reactions between deazidotrimethylsilane and the corresponding bis-phosphine at 140 0C;375 silylation can be achieved by fluorophosphoranes [see equation (13)] to give diphosphazaphosphonium salts (57). Monomeric phosphoramidimidic di-

+

CH,(Ph,P=NSiMe,),

Ph, PF, -,, d 2Me,SiF n=Oor 1

+

chlorides ( 5 8 ) , which polymerize slowly to tetramers on standing, are the A structure initial products from the reaction shown in equation (14).376 RNCl,

+

2Et2NPCl2

-

Et,NPCl,

+

RN=PC12NEt2

(14)

(58)

based on alternate phosphorus and nitrogen atoms arranged at the corners of a cube is favoured for the polymerized product. Hexamethylphosphoramide forms solvates with a large number of lithium salts and with NaI, NaSCN, and NaC104; these salts have been isolated and characterized by i.r. Dipole moments have been reported for 31 organophosphorus compounds, among which are OP(NMe2), and P(NMe2)3.378 Vibrational data and crystal parameters have been obtained for two and the synthesis of a number of PP-diarylisomeric dihydrazides (59),379 phosphinic hydrazides (RC,I-&),P(0)NHNH2 from the corresponding PhO-P /NH-NH U\NH-NH

'P-OPh

4 sI

chloride and hydrazine hydrate in benzene solution has been r e p ~ r t e d . ~ " 1,l-Dimethyl hydrazides R10P(S)(NHR2))(NHNMe,), where R' = Et or Pr 375

376 377

378 379

380

R. Appel and I. Ruppert, 2. anorg. Chem., 1974, 406, 131. A. M. Pinchuk and V. A. Kovenya, J. Gen. Chem. (U.S.S.R.), 1974, 44, 673. D. C. Luehrs and J. P. Kohut, J. Inorg. Nuclear Chem., 1974, 36, 1459. D. Bessere and M. Troquet, Bull. Soc. chim. France, 1974, 845. U. Engelhardf Z. Naturforsch., 1973, 28b, 357. M. I. Shandruk, N. I. Yanchuk, and A. P. Grekov, J. Gen. Chem. (U.S.S.R.), 1973,43,2186.

362

Inorganic Chemistry of the Main-group Elements

and R 2 = E t , Pr, or Bu, have been readily obtained from the respective chlorides.3a1

Compounds containing P-N-P Bonds. The molecule MeN(PF,), has a Czu heavy-atom skeleton, with the P-F bonds staggered with respect to the C-N bond according to electron-diffraction data.,*' The principal parameters are: r(C-N) = 1.479(17) A; r(P-N) = 1.680(6) 8, r(P-F)

= 1.583(2)

A;

LPNP = 116.1(8)0

An unusual reaction takes place when 172,4,5-tetrabromobenzene reacts with NaPPh, in liquid ammonia.383Although sodium bromide is formed, the products are benzene and HN(PPh,),, and not the expected tetrasubstituted benzene. The chloramination of similar N-substituted bis(phosphino)amines gives phosphonium salts [Ph,P(NHR)NPPh,(NH,)]Cl, and a mechanism for this interesting reaction has been Cleavage of the Si-N bond in (Me,Si),NPF, with PF, is the basis of a trifluorophosphazodifluorophosphine new method for preparing F,P=NPF2, but there are dficulties in separation from the Me,SiF bySubstitution reactions with Me,NSiMe, take place initially at the phosphorus(II1) atom in the compound of mixed oxidation state C1,PNMeP(0)C12, but at room temperature isomerization occurs to give C1,PNMeP(0)C1NMe,.386 Further dimethylaminolysis gives disubstitution at the phosphorus(v) centre. Mono-, di-, and tri-methoxy derivatives can also be obtained, the latter two by condensation of (MeO),(MeNH)PO with, respectively, PCl, or MeOPCI,. The expected phosphinimino-phosphines are not obtained from desilylation reactions between R,P=NSiMe, and diorganochlorophosphines as a second mole of the latter adds immediately, giving phosphiniminophosphonium chlorides such as [Me3P=NPMe,PMe,]'C1-.387The mechanism of formation of trichlorophosphazene phosphoryl chloride, Cl,P=NP(O)CI,, from imido-diphosphoryl chloride and PCl, has been investigated using "P-labelled PC15,388and the compound can be reconverted into Cl,P(O)NHP(O)Cl, by formic acid.38gReactions in which the chlorine atoms in the latter are replaced by ammonia or amines have been described. Anhydrous formic acid has been used to replace a chlorine atom by a hydroxy-group in 38 I

N. N. Mel'nikov, T. P. Krylova, and I. L. Vladimirova, J. Gen. Cheni. (U.S.S.R.), 1973, 43, 1627.

'" E. Hedberg, L. Hedberg, and K. Hedberg, J. Arner. Chem. SOC., 1974, 96, 4417.

J. Ellermann and W. H. Gruber, Z. Naturforsch., 1973, 28b, 310. D. F. Clemens and W. E. Perkinson, Inorg. Chem., 1974, 13, 333. 385 G.-V. Roschenthaler, R. Schmutzler, and E. Niecke, 2. Naturforsch., 1974, 29b, 436. 386 R. Keat, J.C.S. Dalton, 1974, 876. ''' W. Wolfsberger, Z. Naturforsch., 1974, 29b, 35. 388 L. Riesel, M. Mauck, and E. Herrmann, 2.anorg. Chem., 1974, 405, 109. 789 L. Riesel, H. H. Patzmann, and H.-P. Bartich, Z. anorg. Chern., 1974, 404, 219. 383 384

Elements of Group V

363

RPCl,=NP(O)Cl, and further aspects of imide-amide rearrangements, shown in equation (15), have been examined.,” New i.r. data

and possible assignments for a series of phosphazenes, including the compounds Cl,P=NSO,Cl, [Cl,PNPCl,NPCl,]PCl,, Cl,P=NPOCl,, and C1,P=NPSCl2, have appeared.392 Further results are now available on the results of ammonolysis of organophosphoranes with potassium amide in ammonia under pressure.393 Particularly important starting materials are the imides R3P=NH, from which can be obtained new phosphazenes such as (60) and (61).

NH

NH

Compounds containing P,N, Rings. Two new series of diazadiphosphetidines (62) have been synthesized from (F,PNMe), and either MeMgI or

Me (62) R = M e , n = 2 or 3 R = O M e , n = l or 2

LiOMe for detailed n.m.r. investigations, which provide information on both the molecular geometry and intramolecular motion.394Values of *JPpcan be reproduced by a product of two parameters which are characteristic of the environment at each atom. 1.r. data for (F,PNMe),, (CI,PNMe),, (Me,N),P=NMe, and [P(NMe,),]+I-395and ,’Cl n.q.r. data for (Cl,PNMe),”‘ have been obtained. 390

391

392 393

394

395 396

V. A. Shokol, G. A. Golik, Yu. N. Levchuk, Yu. P. Egorov, and G. I. Derkach, .I.Gen. Chem. (U.S.S.R.), 1973, 43, 745. A. A. Khodak, V. A. Gilyarov, and M. I. Kabachnik, J. Gen. Chem. (U.S.S.R.), 1974, 44, 241. R. M. Clipsham, J. D. Pulfer, and M. A. Whitehead, Phosphorus, 1974, 3, 235. B. Ross, 2. Naturforsch., 1973, 28b, 359; B. Ross and K.-P. Reek, Chem. Ber., 1974, 107, 2720. R. K. Harris, M. I. M. Wazeer, 0. Schlak, and R. Schmutzler, J.C.S. Dalton, 1974, 1912. P. Haasemann and J. Goubeau, 2. anorg. Chem., 1974, 408, 293. A. D. Gordeev, E. S. Kozlov, and G. B. Soifer, J. Struct. Chem., 1973, 14, 878.

364

Inorganic Chemistry of the Main- group Elements Pyrolysis reactions in which methyl chloride is lost have been carried out on a number of halogeno- and substituted diazadiphosphetidines."' The products are in general cyclophosphazene oligomers and polymers, and, for example, with (C13PNMe)2there is evidence for thc formation of (PNC12)3-9 and a polymer, (PNCI,),, with a molecular weight of 28 000. Details of the structure of the cis-form of (63) have now been published, 'Y' showing exact C2 symmetry but a non-planar P2N2 ring. This is a significant difference

from the trans-form, and it probably results from steric interactions between the cis phenyl groups. Both cis- and trans-forms of a new diazadiphosphetidinedi-imide (64) have been prepared3" from Bu'PCI(=NR)(NRSiMeJ by loss of Me,SiCl. Treatment of (64) with phenyl isothiocyanate replaces the imide groups by sulphur. Cyclophosphazenes in both the ground and excited states have been the subject of new CNDO calculation^^^^^^^ which point to there being significant P-P transannular interaction in P,N,F,. "N-labelled P,N,Cl, has been synthesized4'* and used in an investigation of the mechanism of the reaction between P,N,Cl, and the ammonium salts of carboxylic hcorporation of I5N into the nitrile product indicates that interaction with the ring nitrogen atoms is important. Hexasubstituted triphosphazenes can be synthesized by ring-closure reactions of the type shown in equation (16);404corresponding tetrameric species

result if the bis(dipheny1phosphino)amine is replaced by (65). X-Ray data for the charge-transfer complex P,N,Me,,I, show perturbation of the ring structure to a slight chair conformation, with longer P-N bonds (1.64 A) at the complexed nitrogen atom than at the remaining nitrogens (mean

"' H.-G. Horn, 398

3y9 40" 4"1 402

403 404

Z . anorg. Chem., 1974, 406, 199. G. J. Bullen and P. A . Tucker, Acta Cryst., 1973, B29, 2878. 0. J. Scherer; L. Weber, and N. Kuhn, Chem. Ber., 1974, 107, 552. D. R. Armstrong, M. C. Easdale, and P. G. Perkins, Phosphorus, 1974, 3, 2.51, 2.59. J.-P. Faucher and J.-F. Labarre, Phosphorus, 1954,3, 265; J . Mol. Structure, 1973,17, 159. Yu. N. Pashina and B. I. Stepanov, J. Gen. Chem. (U.S.S.R.), 1974, 44, 433. Yu. N. Pashina and B. I. Stepanov, J. Gen. Chem. (U.S.S.R.), 1974, 44, 440. R. Appel and G. Saleh, Chem. Ber., 1973,106,3455.

365

Elements of Group V

"t

/R2

N/p-NH2 'P==NH

R' I 2R' 1.60 A)."' Significant differences have been detected in the massspectrometric behaviour of arylfluorotriphosphazenes P3N3F,Ar6-,,?depend.~~~ work on ing on the detailed arrangement of the ~ u b s t i t u e n t sContinuing reactions of P3N3Cl, with organometallic reagents, experiments with phenyl-lithium in ether have now been described.""' The products are mixtures of phenylated open-chain phosphazenes which probably result from an initial ring-cleavage reaction to give PhPCl=NPCl,=NPCl,NLi. A new synthetic route to (66), the ring-contracted product obtained by treating P,N,Cl, with a phenyl Grignard reagent, involves reaction between triphenylphosphinimine and P,N,CL"' In addition to compound (66), two isomeric disubstituted products are also formed; with P,N,Cl, both monoand di-substitution are again observed. Details of the structure of (66) from

X-ray data show equality of the P-N distances in pairs, but a significant feature is the equality and shortness of the two exocyclic P-N bonds, implying extensive electron d e l o ~ a l i z a t i o n Several .~~ phosphazo-substituted penta(ary1oxy)triphosphazenes such as (67) have been ~ynthesized.~~'

405

406

407 408 409

P. L. Markila and J. Trotter, Canad. J. Chem., 1974, 52, 2197. C. W. Allen and P. L. Toch, J.C.S. Dalton, 1974, 1685. M. Biddlestone and R. A. Shaw, Phosphorus, 1973, 3, 95. M. Biddlestone and R. A. Shaw, J.C.S. Dalton, 1973, 2740. M. Biddlestone, G . J. Bullen, P. E. Dam, and R. A. Shaw, J.C.S. Chem. Comm., 1974,56. A. A. Volodin, V. V. Kireev, V. V. Korshak, and A. A. Fomin, J. Gen. Chem. (U.S.S.R.), 1973, 43, 2198.

366 Inorganic Chemistry of the Main -group Elements Mono-isocyanato and 4sothiocyanato derivatives P,N,F,(NCX) and P4N4F,(NCX),where X = 0 or S,"l and a hydrazine-bridged diphosphazene system F,P3N,NHNHP,N3F,"'2 can be obtained. Reactions of the latter with acid chlorides, aldehydes, and ketones have been described. Treatment of either P3N3C16,P3N3Cl,NH2, or P3N3C14(NH2),with hexamethyldisilazane gives P,N3C14(NHSiMe3),.413 This compound is of interest as it is the silicon analogue of the di(t-buty1amino)chlorophosphazene; i.r. and mass spectral data for the two species have been An unusual preparative route to a substituted phosphazene has been discovered414during an investigation of the low-temperature ammonolysis of (Me,N),PCl, which leads to a novel compound with the structure (68).

Only one of the possible substitution products in the P3N3C1,-Me2NH system remains to be prepared following the recent isolation of P,N,Cl(NMe2)5.415The product is very susceptible to hydrolysis and yields the corresponding monofluoride on prolonged reaction with antimony trifluoride. The course of reaction in the P,N,Cl,-Et,NH system seems to follow closely that for dime thylamine in giving compounds P3N3C16-,,(NEt,),, where n = 1-4 and 6, which have a predominantly trans, nongeminal structure for n = 2-4.416 Detailed studies on the fluorination of P,N,Cl,NMe, have recently been Anionic fluorinating agents lead to a geminal reaction scheme, and with KSO,F in the absence of solvent the products were members of the series P3N3F,C1,-,NMe2, with n = 1-4. In nitromethane solution, KS0,F gave P,N,F,NMe, as the major product, but with KF in acetonitrile mainly P3N,F4CINMe, was obtained. Reaction with a mixture of SbF, and SbCl, gave a second monofluoride isomer, P,N3FC14NMe,, in which the chlorine atom in the PClNMe, group had been substituted. Friedel-Crafts

411 'lZ

413 '14 415

41h 417

H. W. Roesky and E. Janssen, 2. Naturforsch., 1974, 29b, 174. H. W. Roesky and E. Janssen, Z. Naturforsch., 1974, 29b, 177. A. T. Fields and C. W. Allen, J . Inorg. Nuclear Chem., 1974, 36, 1929. A. Schmidpeter and H. Rossknecht, Chem. Ber., 1974, 107, 3146. P. Clare and D. B. Sowerby, J. Inorg. Nuclear Chem., 1974, 36, 729. W. Lehr and N. Rosswag, Z. anorg. Chem., 1974, 406, 221. B. Green, J.C.S. Dalton, 1974, 1113.

Elements of Group V

367

reactions on a number of chlorodimethylamino-derivatives418 P3N3C16-,(NMe2),, where n = 1-3, and similar piperidine proceed readily at PCl(NMe,) groups but more slowly at PC1, groups. Structures have been given for the phenylated products and factors influencing the position and ease of phenylation discussed. Basicity data for nitrobenzene solutions have now been obtained for the fully substituted oligomers [PN(NMe2)2]3-7, showing a rise in basicity from trimer to hexamer but a decrease for the heptamer.,,' The differences are, however, small and are thought to reflect changes in ring geometry or hybridization. Structural data are now available on two protonated hexakis(dimethy1amino)triphosphazenes, [P,N3(NMe,),H'],[Mo60:9]42' and [P,N3(NMe2)6H+],[CoCG-],*" and changes in the bond distances and angles can be rationalized on the basis of an interruption of the in-plane .rr-bonding system. 'H n.m.r. spectra for many alkoxy-substituted triphosphazenes show evidence of long-range virtual coupling, but the data for P,N,CI,(OBU)~ indicate a non-geminal Sodium salts of substituted phenols react with P,N,Cl,, allowing the isolation of penta- and hexa-substituted derivatives, for which Lr., 31Pn.m.r., and U.V.spectra have been and polycondensation reactions have been carried out between dihydroxyaromatic compounds and P,N3Cl,Ph2.425 Triphosphazenes substituted with three naphthalenedioxy-groups form clathrates with aromatic hydrocarbons, and X-ray studies have been carried out on two such compounds. Evidence has been provided for a fixed position within the channels for the guest, p-xylene, with the 1,9-dioxy but the benzene molecules clathrated in the 2,3-dioxycompound are d i ~ o r d e r e d . ' ~ ~ Dime thylaminofluoro tetraphosphazenes are the products when antimony trifluoride reacts with the non-geminally substituted chlorides P,N,Cl,(NMe2), and P4N4C13(NMe2),.428 In each case, three isomeric fluorides, which can be separated by preparative g.l.c., are obtained, and structures can be assigned on the basis of n.m.r. data. Fluorination is considered to proceed via co-ordination of the antimony trifluoride to a ring nitrogen atom and, to account for product isomer ratios, there is the possibility of isomerization taking place during the chloride-replacement step. An observation during

'*'S. Das, R. A . Shaw, and B. C. Smith, J.C.S. Dalton, '19 420

421 422 423

424

425 426 427 428

1973, 1883.

S. Das, R. A. Shaw, and B. C. Smith, J.C.S. Dalton, 1974, 1610. S. N. Nabi and R. A . Shaw, J.C.S. Dalton, 1974, 1618. H. R. Allcock, E. C. Bissell, and E. T. Shawl, Inorg. Chem., 1973, 12, 2963. A. L. Macdonald and J. Trotter, Canad. J . Chem., 1974, 52, 734. T. P. Zeleneva, I. V. Antonov, and B. I. Stepanov, J . Gen., Chem. (U.S.S.R.), 1973, 43, 1000. I. B. Telkova, V. V. Kireev, V. V. Korshak, A . A. Volodin, and A. A. Fomin, J. Gen. Chem. (U.S.S.R.),1973, 43, 1247. M. Kajiwara and H. Saito, Nippon Kagaku Kaishi, 1974, 464. H. R. Allcock, M. T. Stein, and E. C. Bissell, J. Amer. Chem. SOC., 1974, 96, 4795. H. R. Allcock and M. T. Stein, J. Amer. Chern. SOC., 1974, 96, 49. D. Millington and D. B. Sowerby, J.C.S. Dalton, 1973, 2649.

368 Inorganic Chemistry of the Main-group Elements these experiments that SbF, could also substitute dimethylamino-groups led to an examination of the SbF,-P,N,(NMe,), system."" This proved to be an alternative route to the mixed amino-fluorides, and compounds in the series P4N4Fn(NMeJ8-,,, where n = 1, 2(4 isomers), 3(3 isomers), 4(3 isomers), and 5(3 isomers), could be isolated. From the isomer ratios and structures assigned to the products, replacement of NMe2 groups follows a stepwise non-geminal path, with a tendency to form larger amounts of the transrather than the cis -isomer. The ring conformation in three newly investigated cyclotetraphosphazenes shows a ca. D,, (saddle) arrangement in 1,trans -3,cis -5,trans -7tetrakis(dimethylamino)tetrafluoro-cyclotetraphosphazene430(see Figure 10) and a CZh(chair) in both l,cis-3,trans-5,trans-7-tetrachlorotetraphenylcyclotetraphosphazene43' (see Figure 11) and 1,trans-5-dichlorohexakis(dimethylamino)-cyclotetraphosphazene.432 In each case there is a detailed consideration of the molecular parameters and comparison with previous data. Structures have been assigned by X-ray and n.m.r. methods to two isomeric tetrachlorophenyl derivatives P4N4C14Ph4.433 Both are geminally substituted compounds with respectively 1,3- and 1,5-structures. A complete X-ray structure for P,N,(NMe2),,W(C0)4 shows an unusual feature as the octahedral arrangement around the tungsten is completed by a ring nitrogen and a nitrogen from a dimethylamino-group (see Figure 12).434The compound appears to be a simple a-complex but co-ordination

Figure 10 The structure of cis,trans,cis,tran.s-P4N4F4(NMe2), (Reproduced from J.C.S. Dalton, 1974, 1162) 429 430

431 432

433

434

D. Millington and D. B. Sowerby, J.C.S. Dalton, 1974, 1070. M. J. Begley, D. Millington, T. J. King, and D. B. Sowerby, J.C.S. Dalton, 1974, 1162. A. H. Burr, C. H. Carlisle, and G. J. Bullen, J.C.S. Dalton, 1974, 1659. G . J. Bullen and P. E. Dann, J.C.S. Dalron, 1974, 705. M. Biddlzstone, S. S. Krishnamurthy, R. A. Shaw, M. Woods, G. J. Bullen, and P. E. Dann, Phosphorus, 1973, 3, 179. H. P. Calhoun, N. L. Paddock, and J. Trotter, J.C.S. Dalton, 1973, 2708.

369

Elements of Group V

Figure 11 The structure of cis,cis,trans,trans -P,N,CLPh, (Reproduced from J.C.S. Dalton, 1974, 1659) to tungsten leads to significant changes in the phosphazene, as shown by the variation in the P-N bond lengths. A pair-wise variation in the P-N bond distances is found in the structure of [P4N4Me9]”Cr(C0)J-, in which the extra methyl group is attached to a ring nitrogen atom.435The ring conformation is greatly distorted from the ‘tub’ form in P4N4Me8,probably so as to minimize methyl-methyl contacts between the NMe and PMez groups.

d

(131

Figure 12 General view of the molecule P4N4(NMe&W(C0)4; N-7 is directly below P-2 (Reproduced from J.C.S. Dalton, 1974, 1162) 435

H. P. Calhoun and J. Trotter, J.C.S. Dalton, 1974, 377.

370

Inorganic Chemistry of the Main -group Elements As observed in the corresponding trimer reactions, the recently reported reactions between P,N,Cl, and sodium thiolates follow a geminal reaction path, but in contrast only tetrasubstituted products with 1,1,5,5-structures were generally isolated.436With more forcing conditions, ring breakdown took place to give trithiophosphites and trithiophosphates. Fluorination of P,N,Cl,,, with KSO,F follows the same strictly nongeminal scheme that was found in similar reactions with the lower homologues, and compounds with all degrees of substitution are formed.437 N.m.r. data point to isomer mixtures in some cases. Crystallographic data are beginning to accumulate on the higher phosphazene homologues, and information is now available on a protonated pentamer [P5N5MeIoH,]C U C ~ , , H , Oand ~ ~on ~ P6N6(OMe),2.439 In the former the protons are attached to ring nitrogen atoms and the ring conformation is similar to that in the pentameric bromide, while the methoxy-compound is centrosymmetric, bond lengths. The with a double tub conformation and equal P-N methoxy-group orientations are discussed in detail and the major features of the structures are considered to be consequences of non-bonded interactions. Compounds containing Heteroatom Ring Systems. A four-membered 'diazaphosphete' (69) is the product from reaction between ammonium chloride C1,C-C-N

II I1

N-PCI, (69)

and C13CCC12N=PC13.440 A number of new six-membered P-N-Si heterocycles, including (70), have been isolatedTl while eight-membered systems (71) are obtained from chlorine elimination between dialkyl dichlorophosphoramidates (R'0)2P(0)NCl, and c h l o r o ~ i l a n e ~ . " ~ ~ Me /N\

Me2SI I

SiMeZ

M e N \ P Nx pMe R /'

(70) R = M e or Ph X = lone pair, S, or NSiMe,

(R' O),P=N-SiClR'

I I

I I

0

0

R'CISi-N=P(OR'

(71) R'

= Et

jZ

or Pr

RZ= C1 or Me

A. P. Carroll, R. A. Shaw, and M. Woods, J.C.S. Dalton, 1973, 2736. N. L. Paddock and J. Serriqi, Canad. J. Chem., 1974, 52, 2546. 438 H. P. Calhoun and J. Trotter, J.C.S. Dalton, 1974, 382. 439 M. W. Dougill and N. L. Paddock, J.C.S. Dalton, 1974, 1022. 440 V. P. Kukhar', T. N. Kasheva, and E. S. Kozlov, J . Gen. Chem. (U.S.S.R.),1973,43,741. 441 H. H . Falius, K. P. Giesen, and U. Wannagat, Z . anorg. Chem., 1973, 402, 139. 442 A. M. Pinchuk and A. M. Khmaruk, J. Gen. Chem. (U.S.S.R.), 1973, 43, 1849; A. M. Pinchuk, A. M. Khmaruk, and T. V. Rovalevskaya, J. Gen. Chem. (U.S.S.R.),1974,44,441. 436

437

37 1 Elements of Group V The mixed phosphorus-sulphur compound (72) reacts with AgF, in carbon tetrachloride to produce an S-F bond, and the remaining chlorines can be substituted with morpholine or pyrrolidine.""' A tetrameric analogue of (72), (NPCl,),NSOCl, has been isolated in small amounts from the mixture obtained when SO,(NH,), and [Cl,P=NPCl,NPCl,]'[PC16]- react,""" while a new P-N-S system (73) is formed when the linear phosphazene ClSO,N=PCl,NPCl,NMeSiMe, is heated."4s

(72)

(74)

(73)

Attack occurs at a P-C1 bond in the heterocycle (NSOF),NPCl,, on A new structure (74), based on X-ray data, ammonolysis and arninoly~is.""~ has been given for the compound S3N5PF,, obtained from PF, and Me3SiN=-S=NSiMe3.447This has a strong relationship to the S4N4structure but here two opposite sulphur atoms are nitrogen-bridged and one sulphur is replaced by a PF, group.

Bonds to Oxygen.-Compounds of Lower Oxidation State. Mixed sulphurphosphorus anhydrides result when sulphonic acids and dialkyl hydrogen phosphites react according to equation (17)."'*Further work on the preparation of trimethylsilyl esters of phosphorous acids has been carried out by R'S0,Ag

+

CIP(ORZ),

-

AgCl

+

R1S0,0P(OR2), + AgCl

(17)

Cavell and co-w~rkers.'"~ Four routes have been given to compounds of the type R,PESiMe,, where R = F or CF, and E = O or S, and reactions with hydrogen chloride and dimethylamine have been reported. Tautomerism in the products from phosphorus trichloride and 0diphenols (75a) and (75b) can be investigated by 31Pn.m.r. spectroscopy,49° H

(7Sa) 443

(75b)

H. H. Baalmann and J. C. van de Grampel, Rec. Trau. chim., 1973, 92, 1237. 444 C. Voswijk and J. C. van de Grampel, Rec. Trau. chim., 1974, 93, 120. 445 H. W. Roesky and W. Grosse Bowing, 2. anorg. Chem., 1974, 406, 260. 446 W. Heider, U. Klingebiel, T.-P. Lin, and 0. Glemser, Chem. Ber., 1974, 107, 592. 447 J. Weiss, I. Ruppert, and R. Appel, 2. anorg. Chem., 1974, 406, 329. ""' M. G. Gubaidullin and L. M. Kovaleva, J. Gen. Chem. (U.S.S.R.), 1973, 43, 2638. 449 R. G. Cavell, R. D. Leary, A. R. Sanger, and A. J. Tomlinson, Inorg. Chem., 1974,13, 1374. 450 A . Munoz, M. Koenig, G. Gence, and R. Wolf, Compt. rend., 1974, 278, C, 1353.

372 Inorganic Chemistry of the Main-group Elements to show that the bulk of the compound is in the five-co-ordinate form in dichloromethane but in the alternative form in DMF. A six-co-ordinated phosphorus anion (76) is formed when 2-organo-l,3,2-benzodioxaphos-

(76)

pholes react with catechol in the presence of base<'* on thermal dissociation, either hydrogen or an alkane is eliminated, depending on the nature of R. An improved route to germanium(r1) compounds depends on the use of hydrated sodium hypophosphite; the first product isolated with GeCI, is Ge(HP0,).45' The crystal structures of La(H2P02)37Hz04'3 and the europium analogue454are closely similar, each containing three structurally different hypophosphite ions. An i.r. and d.t.a. study of the effect of heat on Zn(HP0,),2.5H20, ZnzHz(HP03)3,Hz0,Zn,H4(HP03)5,1.5Hz0, and ZnH,(HPO,), has been carried Cation co-ordination and hydrogen bonding in hydrated tetrasodium hypophosphate are similar to those in the corresponding diphosphate, according to X-ray data.456The anion here has C, symmetry, with a staggered conformation and a P-P distance of 2.20 A; co-ordination around each phosphorus is flattened tetrahedral. and ~ Kinetic studies on the hypophosphite reduction of p e r ~ h e n a t e , ~ ~ ~ ~c e r i u r n ( ~ v ) ~ ~ ~ chlorothallium(r~r)~'~ and the reduction of ~ a n a d i u r n ( v )and by phosphite are reported. Phosphorus(v) Compounds. Dipole moments for a series of phosphine and arsine chalcogenides point to the arsines being of greater polarity and for polarity to increase generally in the order oxide < sulphide < ~elenide.,~' Trends in the values of the derived bond moments are discussed in terms of the relative amounts of double-bond character. Displacement reactions in the systems R:M'O,BF,-R~Mz0, where R' and R' =Me, Et, or Pr and M' and M" =N,P, or As, can be followed by n.m.r. spectroscopy, showing "* 4s3 454

455 4s6

4s7 458

459 460

461

M. Wieber, K. Forouchi, and H. Klingl, Chern. Ber., 1973, 107, 639. P. S. Poskozirn and C. €?.Guengerich, Inorg. Chem., 1974, 13, 241. V. M. Ionov, L. A. Aslanov, V. R. Rybakov, and M. A. Porai-Koshits, Souiet Phys. Cryst., 1973, 18, 250. V. M. Ionov, L. A. Aslanov, M. A. Porai-Koshits, and V. B. Rybakov, Soviet Phys. Cryst., 1973, 18, 252. M. Ebert and M. Pelikhnovi, Monatsh., 1974, 105, 11. D. S. Emmerson and D. E. C. Corbridge, Phosphorus, 1973, 3, 131. S. J. Paton and C. H. Brubaker, jun., Inorg. Chem., 1974, 13, 1402. K. S. Gupta and Y. K. Gupta, Inorg. Chem., 1974, 13, 851. K. K. Sen Supta, B. B. Pal, and D. C. Mukherjee, J.C.S. Dalton, 1974, 226. S. K. Mishra, P. D. Sharma, and Y. K. Gupta, J. Inorg. Nuclear Chem., 1974, 36, 1845. R. R. Carlson and D. W. Meek, Inorg. Chem., 1974, 13, 1741.

373

Elements of Group V

displacement in the order N 3 As > P.""" 1.r. and n.m.r. measurements over a temperature range indicate the presence of only one conformer for MeXP(=Y)Me2, where X,Y = 0 or S, but with MeSP(=Y)Et2 in the Iiquid phase two conformers are A stable tetrakis(trimethylsi1oxy)phosphonium iodide can be produced from Me,SiI and (Me,SiO),PO, but the corresponding bromide can be obtained only at low ternperat~res.~~" The iodide is also obtainable by treating trimethyl phosphate with four moles of Me3SiI. Details of the structure of phenylthiophosphonic anhydride (77) now publishedM5show a boat (ca. C,) ring conformation, with a trans arrangement of substituents. S\p./o\p/

Ph"

I

S P ('h

(77)

Although methylphosphonic acid has a polymeric structure, the compound sublimes readily at 150 "C and 1mmHg, and mass-spectrometric examination points to the trimer [MeP(0)0I3 being the most abundant is the predominant species from the species in the v a p o ~ r A . ~ dimer ~~ corresponding sulphur compound, but impurities such as [MeP(S)O], and [MeP(S)O], were also detected. Scrambling reactions between a number of phosphorus centres, i.e. MeP:, MeP(O):, or MeP(S):, and Me2Si: show that chlorine atoms are preferentially bonded to ~ilicon."~' Samples of methyl(MeO),P(0)O[P(O)OMe].P(O)(OMe2)2, where ated polyphosphates n =0-2, can be obtained by molecular distillation of an equilibrated mixture of P,O, and trimethyl p h o ~ p h a t e . " ~ ~ Thermal decomposition of 1-hydroxyethylidenediphosphonicacidM9gives a polyacid containing the cyclic anion (78), previously recognized in the product from the reaction of acetyl chloride and phosphorous acid.

(78) 462 463

464 465

466 467

468 469

R. Bravo, M. Durand, J.-P. Laurent, and F. Gallais, Compt. rend., 1974, 278, C, 1489. A. B. Remizov, I. Ya. Kuramshin, A. V. Aganov, and G. G. Butenico, Doklady Chem., 1973, 208, 134. H. Schmidbaur and R. Seeber, Chem. Ber., 1974, 107, 1731. J. J. Daly and F. Sam, J.C.S. Dalton, 1973, 2032. K. Moedritzer, Phosphorus, 1974, 3, 219. K. Moedritzer and J. R. Van Wazer, Inorg. Chern., 1973, 12, 2856. R. A. Schep, S. Norval, and J. H. J. Coetzee, Inorg. Chem., 1973, 12, 2711. A. J. Collins, G. W. Fraser, P. G. Perkins, and D . R. Russell, J.C.S. Dalton, 1974, 960.

374 Inorganic Chemistry of the Main -group Elements Evidence for five-co-ordinate phosphorus(v) species with essentially square-pyramidal structures has been observed in a number of spirocyclic Complete structural data are available systems, such as (79)'" and (80).471,472

for (80) where R=Me473or F;474in the latter the co-ordination is intermediate between a trigonal bipyramid and a square pyramid. Factors influencing the structures are discussed in detail, but a major feature seems to be the reduced ring strain in the square-pyramidal form. Six-co-ordinated phosphorus(v) compounds are still relatively rare, but recently three such compounds containing three different bidentate oxygen ligands (derived from ethylene glycol, mandelic acid, benzil, or 2-hydroxy2-methylpropionic acid) have been synthe~ized.~~' Detailed structures have now been determined for (81) by electron diffraction476and for two substituted 1,3,2-dioxaphosphorinansby X-ray

(81) X = O o r S

In the cyclic acyl phosphate (82), the C,O,P ring has a half chair c ~ n f o r r n a t i o nwhile , ~ ~ ~ the compound obtained from a MichaelisArbuzov reaction of l-phospha-2,8,9-trioxa-adamantaneand benzyl chloride has been shown by an X-ray study to have a bicyclic structure (83).480 There is now considerable work o n metal complexes of substituted phosphorus-oxygen species. For example, the Group 111 trialkyls lose one mole of an alkane with phosphinic acids X,P(O)OH, where X = M e , H, F, or C1, 470 471 472

473 474 475 470

477 478 47Y

480

J. A. Howard, D. R. Russell, and S. Trippett, J.C.S. Chem. Comm., 1973, 856.

R. R. Holmes, J . Amer. Chem. SOC.,1974, 96, 4143. H. Wunderlich, D. Mootz, R. Schmutzler, and M. Wieber, Z. Naturforsch., 1974, 29b, 32. H. Wunderlich, Acta Cryst., 1974, B30, 939. H. Wunderlich and D. Mootz, Acta Cryst., 1974, B30, 935. M. Koenig, A. Munoz, D. Houalla, and R. Wolf, J.C.S. Chem. Comm., 1974, 182. V. A. Naumov, V. N. Semashko, A. P. Zav'yalov, R. A. Cherkasov, and L. N. Grishina, 1. Struct. Chem., 1973, 14, 739. R. E. Wagner, W. Jensen, W. Wadsworth, and Q. Johnson, Acta Cryst., 1973, B29, 2160. W. Saenger and A. Mikolajczyk, Chem. Ber., 1973, 106, 3519. G. D. Smith, C. N. Caughlan, F. Ramirez, S. L. Glaser, and P. Stern, J. Amer. Chem. SOC., 1974, 96, 2698. S. R. Holbrook, D. van der Helm, and K. D. Berlin, Phosphorus, 1974, 3, 199.

Elements of Group V

375

to give R,MO(O)PX, species which are associated through bridging X2P02 groups.*" Vibrational data point to trimerization, with puckered twelvemembered rings, for M = Al but dimerization when M = Ga or In.482Complex formation between tin(rv) chloride and Me,P(0)OMe,"83Me,P(0)C1,*83 (RO),P(O)SMe,"8' or Ph(RO)P(0)H485gives in general 1:2 adducts which may be mixtures of geometric isomers. The donor site is the phosphoryl oxygen atom in all cases. Different kinds of tin species, e.g. R2Sn(P02H,)2, R2SnP03X ( X = F or OH), and (R,Sn),(PO.&, result when dialkyltin dichlorides and the sodium salts of the acid react in w a t e r y and implicationson their structures follow from i.r. and ""Sn Mossbauer data. Complex compounds also result when triethyl phosphate*" or tetraethyl methylenedipho~phonate~~~ and a wide range of metal halides react in the 100-250 "C temperature range. Representative formulae for the former are M[OOP(OEt),], for M=Al, Ga, In, Sc, Y, Ti, V, Cr, or Fe and M[OOP(OEt),], for M = Fe, Cu, or VO, but polymeric structures are indicated on the basis of insolubility and high thermal stability. Magnetic and spectral measurements for these and similar complexes have been obtained and correlated~'" Species which involve a bridging chlorine atom in addition to phosphinate bridges have been recognized as the products from anhydrous CrC1, reactions with the appropriate phosphinic acid.490(See also refs. 338 and 339).

Monophosphates. A timely review491surveys quantum-mechanical calculations on 3d orbital participation in bonding, and, in addition to data on 481

482

483

484

48s

486

487 488 489

490

491

B. Schaible, W. Haubold, and J. Weidlein, Z . anorg. Chem., 1974, 403, 289. B. Schaible and J. Weidlein, Z. anorg. Chem., 1974, 403, 301. A. N. Pudovik, I. Ya. Kuramshin, E. G. Yarkova, A. A. Muratova, A. A. Musina, and R. A. Manapov, J. Gen. Chem. (U.S.S.R.), 1973, 43, 1220. I. Ya. Kurashin, A. A. Muratova, E. G. Yarkova, A. A. Musina, F. Kh. Izmailova, and A. N. Pudovik, J. Gen. Chem. (U.S.S.R.), 1973, 43, 1446. A. A. Muratova, E. G. Yarkova, V. P. Plekhov, N. R. Safiullina, A. A. Musina, and A. N. Pudovik, J. Gen. Chem. (U.S.S.R.), 1973, 43, 1677. T. Chivers, J. H. G. van Roode, J. N. R. Ruddick, and J. R. Sarns, Canad. J . Chem., 1973, 51, 3703. C . M. Mikulski, L. L. Pytlewski, and N. M. Karayannis, Z . anorg. Chem., 1974, 403, 200. C. M. Mikulski, N. M. Karayannis, L. L. Pytlewski, R. 0. Hutchins, and B. E. Maryanoff, J. Inorg. Nuclear Chem., 1973, 35, 4011. C . M. Mikulski, N. M. Karayannis and L. L. Pytlewski, J. Inorg. Nuclear Chem., 1974, 36, 971. H. D. Gillman, P. Nannelli, and B. P. Block, J. Inorg. Nuclear Chem., 1973, 35, 4053. M. E. Dyatkina and N. M. Klimenko, J. Stmct. Chem. (U.S.S.R.), 1973, 14, 157.

3 76 Inorganic Chemistry of the Main -group Elements PO:- and PF;, the sulphur, chlorine, silicon, and aluminium analogues have been treated. New a b initio calculations have been reported on PO:-,'" and data from X-ray emission and p.e.s. for several second-row oxyanions, including PO:-, give good agreement with the results of such computation~.,~~ Refinement of the structure of H,PO,,iH,O using neutron-diffraction data shows the presence of two different acid molecules hydrogen-bonded to each other and to the water The effect of "0 on the p H of solutions of H3PO4 has been investigated, as previous observations implied that hydrogen-bonding tendencies were lowered by the presence of As expected, the p H of the acid in pure H,"O is significantly lower than in H,160. Evidence has been presented for the formation of the radical -P(OH)l by y-irradiation of phosphoric acid in sulphuric acid but with arsenic acid the species produced is .As(OH),."~~ Structural studies for a number of hydrogen monophosphates are concerned with the hydrogen atom positions, for example in NaH,PO,,""' NH,H,P04,498and Ca(H2P04)2.499 Problems of crystal twinning in stercorite (NaNH,HPO,,H,O) have been inve~tigated,'~~ and the structure of synthetic magnesium whitlockite, Ca18Mg2H2(P04)14, has been shown to be hexagonal (space group R 3 c ) , with similarities to the p -Ca3(P04), Co-ordination about sodium, which gives rise to a complex of composition [Na6F(OH,),,]5+,is the feature of interest in the structures of the double salt NaF,2Na3PO,, 19 H 2 0 and its arsenic analogue.502In brazilianite, NaA1,(P04)2(0H)4,the structure is based on chains of edge-sharing A106 octahedra linked by PO, tetrahedra, giving cavities which contain the sodium ions.5o3 show the presence of P03F2Structures for LiKP03FSo4 and p -Na2P03FSo5 tetrahedra, and in SnP03F506there are sheets of P03F2- ions alternating with tin(I1) ions, giving a structure very similar to that of SnHPO,. Powder data for Na3P03S,12H,0, the nonahydrate, and the anhydrous material give unit-cell dimensions for each form,507and single-crystal data 4q2 491 494

496

497 49H

4y9 500

501

'04 505

H. Johansen, Theor. Chim. Acta, 1974, 32, 273. J. A. Connor, I. H. Hillier, M. H. Wood, and M . Barber, J.C.S. Faraday 11, 1974,70, 1040. B. Dickens, E. Prince, L. W. Schroeder, T. H. Jordan, Acta Cryst., 1974, B30, 1470. A. 1. Kudish, D. Wolf, and S. Pinchas, J. Inorg. Nuclear Chem., 1973, 35, 3637. I. S. Ginns, S. P. Mishra, and M. C. R. Symons, J.C.S. Dalton, 1973, 2509. M. Catti and G. Ferraris, Acta Cryst., 1974, B30, 1. A. A. Khan and W. H. Baur, Acta Cryst., 1973, B29, 2721; A. W. Hewat, Nature, 1973, 246, 90. B. Dickens, E. Prince, L. W. Schroeder, and W. E. Brown, Acta Cryst., 1973, B29, 2057. G. Ferraris and M. Franchini-Angela, Acta Cryst., 1974, B30, 504. R. Gopal, C. Calvo, J. Ito, and W. K . Sabine, Canad. J. Chem., 1974, 52, 1155. W. H. Baur and E. Tillmanns, Acta Cryst., 1974, B30, 2218. B. M. Gatehouse and B. K . Miskin, Acta Cryst., 1974, B30, 1311. J. L. GalignB, J. Durand, and L. Cot, Acta Cryst., 1974, B30, 697. J. Durand, L. Cot, and J. L. Galignk, Acta Cryst., 1974, B30, 1565. A. F. Berndt, Acta Cryst., 1974, B30, 529. M. Palazzi, Bull. SOC. chim. France, 1973, 3246.

Elements of Group V

377

for the imidodiphosphate Na4(P03NHP03),10H20 give molecular parameters similar to those in the diphosphate analogue.5o8 In addition, the hydrogen-bond systems in these two compounds are virtually identical, implying that the imido-hydrogen atom is effectively blocked from participation by its position. The spectra of lithium phosphate glasses doped with transition elements can be correlated with octahedral co-ordination for Cr3+,Mn3+,Fe2+,Fe3+, Ni2+, and Cu2+,while tetrahedral co-ordination is more appropriate for CO'+.~O~ 1.r. and Raman spectra have been measured for LiM"XB4, where M"= Mg, Ni, Co, Mn, Fe, or Cd and X = P or Dehydration of M&(P04)2,22H20to the octahydrate is speeded up by adding MgHP04,3H20and Na2C03.5" New i.r. and Rarnan data for a-zirconium phosphate indicate asymmetry in the lattice water rn01ecules,~~'and exchange of labelled phosphate between an aqueous solution and the solid exchanger has been reexamined.513Forward and reverse Li-K exchange isotherms have been determined on crystalline zirconium p h o ~ p h a t e , 5and ~ ~ ~to avoid hydration complications, the system has been investigated in molten LiN03-KN03 Exchange reactions using the half-exchanged form, mixtures at 300 0C.514b A zirNaZrH(P04)2,5H20, have also been extensively conium phosphosilicate exchanger can be used to separate neptunium and plutonium.517 Three new phosphomolybdate structures, Na,[H2Mo,P,023(H20)10],518 Na3[H6M09P034(H20)r],519 and (NH4)5[HMo5P2024(H20)3],520 have been determined, each showing significant new features. The formula &[P2W,,O,,],xH2O is suggested for 18-tungsto-2-phosphoric acid on the basis of po tentiome tric titrations in a number of non-aqueous Similar basicity measurements point to an increase in the number of dissociable protons in molybdo-phosphoric acids as the molybdenum atoms are replaced by ~anadium.~"

50H '09 'lo 5"

'12

'14

515

516

517

'I8 519

520

'*'

M. L. Larsen and R. D. Willett, Acta Cryst., 1974, B30, 522. M. Berretz and S. L. Holt, J. Inorg. Nuclear Chem., 1974, 36, 49. M. Th. Paques-Ledent and P. Tarte, Spectrochim. Acta, 1974, 30A, 673. T. Kanazawa, T. Umegaki, and E. Wasai, Chem. Letters, 1974, 817. S. E. Horsley, D. V. Nowell, and D. T. Stewart, Spectrochim. Acta, 1974, 30A, 535. M. K. Rahman and J. Barren, J. Inorg. Nuclear Chem., 1974, 36, 1899. (a) G. Alberti, U. Constantino, S. Allulli, M. A. Massucci, and N. Tomassini, J. Inorg. Nuclear Chem., 1974, 36, 653; (b) ibid., p. 661. G. Alberti, U. Constantino, and J. P. Gupta, J. Inorg. Nuclear Chem., 1974,36,2103, 2109. S. Allulli, A. La Ginestra, M. A. Massucci, M. Pelliccioni, and N. Tomassini, Inorg. Nuclear Chem. Letters, 1974, 10, 337. R. Ooms, P. Schonken, W. D'Olieslager, L. Baetslt, and M. D'Hont, J. Inorg. Nuclear Chem., 1974, 36, 665. B. Hedman, Acta Chem. Scand., 1973, 27, 3335. R. Strandberg, Acta Chem. Scand. (A), 1974, 28, 217. J. Fischer, L. Ricard, and P. Toledano, J.C.S. Dalton, 1974, 941. L. P. Maslov and N. A. Tsvetkov, J. Gen. Chem. (U.S.S.R.), 1973, 43, 954. N. V. Cheu and N. A. Polotebnova, Russ. J. Inorg. Chem., 1973, 18, 1157.

378 Inorganic Chemistry of the Main-group Elements Apatites. Interest in this subject continues in view of its importance in biological systems. A hydroxylapatite with similar properties to biological apatites results when ammoniacal CaCl, and ammonium phosphate solutions are added dropwise to an ammonia buffer at pH9.523The uptake of lead by synthetic calcium hydroxylapatite has been The value of i.r. spectroscopy in studying substituted apatites is stressed by Trombe and M ~ n t e land , ~ ~the ~ technique has been used to study calcium hydroxylapatite and its is0topically substituted species526and the fluoride Ca5(P04)3F.527*52” Hydroxylapatite decomposes slowly in dry air at 1250 “C, contrary to reports that it is stable to 1450”C, giving Ca3(P04),and Ca4P,09.529 The existence of oxyapatite, Ca,,(P04)60, has been confirmed, and the compound is readily prepared by heating a carbonated apatite at between 800 and 1000 OC.”’ At higher temperatures, the lattice is degraded, however. Conversion into a peroxy species occurs on heating at ca. 900°C in a stream of oxygen.531The thermal behaviour of basic calcium phosphates indicates the formation of pseudo-apatitic structures when Ca:P is greater than 3 :2,532and new apatite-like structures with the composition M9+yNa,(Po4)&+zy02, where M=Ca or Sr, can be prepared by direct reaction between M,(PO4)2 and Na,B40,,10Hz0 at 1400 0C.533 The fluorine in fluoroapatite can be substituted by chlorine on treatment with an NO,-NOC1 mixture at 1000”C,534and the B-type carbonate apatites lose carbon dioxide on heating between 700 and 1000 “C, giving CaO and l~ydroxylapatite.”~ X-Ray data indicate strong similarities between the structure of strontium chloroapatite and the fluoro- and hydroxyanalog~~es.’~~

Diphosphates. Recent calorimetric measurements have been used to give thermodynamic data on the ionization of diphosphoric acid537and the formation of [MP207]3-,where M=Li, Na, or K.’38 Methods are now available for the formation of the hydrated salts NaAlP,O,, Ga,(P,O,),, and P. Jervae and H. E. L. Madsen, Acta Chem. Scand. (A), 1974, 28, 477. W. S. Chicherur and S. V. Chiranjeevi Rao, Indian J. Chem., 1973, 11, 603. 5 2 5 3.-C. Trombe and G. Montel, Compt. rend., 1974, 278, C, 777. B. 0. Fowler, Inorg. Chem., 1974, 13, 194, 207. s27 D. M. Adarns and I. R. Gardener, J.C.S. Dalton, 1974, 1505. D. K. Arkhipenko, B. A . Orekhov, and R. G . Knubovets, Optics and Spectroscopy, 1973, 34, 425. ’” T. R. Narayanan Kutty, Indian J. Chern., 1973, 11, 695. 530 J.-C. Trombe, Ann. Chim. (France), 1973, 8, 251. s31 J.-C. Trombe, Ann. Chirn. (France), 1973, 8, 335. s32 A. Delay, C. Friedli, and P. Lerch, Bull. SOC.chim. France, 1974, 828, 839. 533 C. Calvo and R. Faggiani, J.C.S. Chem. Cornm., 1974, 714. 534 J.-C. Trombe and G. Montel, Cornpt. rend., 1974, 278, C, 1227. 5 3 5 J.-C. Labarthe, G. Bonel, and G. Montel, Ann. Chm. (France), 1973, 8, 289. K. Sudarsanan and R. A. Young, Acta Cryst., 1974, B30, 1381. ”’ V. P. Vasil’ev, S. A. Aleksandrova, and L. A . Kochergina, Russ. J. Inorg. Chem., 1973, 18, 1549. 538 V. P. Vasil’ev and S. A. Aleksandrova, Russ. J. Inorg. Chem., 1973, 18, 1089. 523

524

”‘ ’”

Elements of Group V

379

In4(P207)3.539 Equilibrium constants for complex formation between di- or other short-chain poly-phosphates and [Cu(NH,),T' are not in the order expected on the basis of anion charges, probably indicating different structures for the c~mplexe~.'"~ The species obtained from Mn" and similar short-chain phosphates have been investigated by polarography and paper ~hromatography.~"'An SN2-type process with activation energies in the range 19-28 kcal mol-1 is envisaged for the hydrolysis of both di- and triphosphate in a series of mixed aqueous A POP angle in the region of 130" is found in the structures of both ~P,0,,3H,05"3and KzH,P,07,~H,0,5"'while in the latter the bridge oxygen appears to be bonded to potassium and the anions are connected in a spiral form by strong hydrogen bonds. In KAlP,O,, the bridge angle is reduced to 123.2", with the two PO, groups having an almost staggered conformat i ~ n . ~The " ~ bridge and terminal P-0 distances are 1.607 and 1.509& respectively, similar to those in the structures mentioned above.

Cyclic Metaphosphates. Dehydration of NaH2P04, Na2HP04, and Na,PO, with n-butyric, isobutyric, or succinic anhydrides in acetic acid follows the same route as acetic anhydride, giving trimetaphosphates as the major Conditional stability constants for the formation of species which appear to involve electrostatic interactions only have been determined for the systems involving Ca", Sr2+,ZnZ+,and Co2' and the tri-, tetra-, hexa-, and octa-metaphosphate anions.54' A new preparation has been reported for the blue titanium(rr1) tetrametaphosphate Ti4(P,Ol2),,which on heating gives P,O, and TiP,O,.'"" Full details of the structure of m4(P40,2)have now been reported? and in contrast to previous observations the anion here has 3 (S,) symmetry. This points to flexibility of the ring, which can adopt a conformation best suited to the cation. Exocyclic P-0 distances are 1.44 and 1.51 A, while the P-0-P bridge distances and angles are 1.6213, and 133.3", respecand a tively. The hexametaphosphate cUzLi2P60~8has been p~epared,5'~ crystallographic study shows terminal and ring P-0 distances of 1.48 and 1.59 A, re~pectively.~'~ Polyphosphates. The force field of the triphosphate ion P301,'- has been estimated, leading to the forms of the normal vibrations and assignment of 539 540

541

542 543 544

545 546 547 548 549

551

A. Muck, T. Hynie, J. Stejskal, and B. HAjek, Z.Chem., 1974, 14, 69. H.Waki, K. Yoshimura, and S. Ohashi, J. Inorg. Nuclear Chem., 1974, 36, 1337. S. Aoki and Y. Arai, Nippon Kagaku Kaishi, 1974, 60. M. Watanabe, Bull. Chem. SOC.Japan, 1974, 47, 2048. Y.Dumas and J. L. GalignC, Acta Cryst., 1974, B30, 390. Y.Dumas, J. L. Galignk, and J. Falgueirettes, Acta Cryst., 1973, B29, 2913. H.N. Ng and C. Calvo, Canad. J. Chem., 1973, 51, 2613. M. Watanabe, H. Usami, and M. Sugase, Bull. Chem. SOC. Japan, 1973, 46, 2885. G. Kura, S. Ohashi, and S. Kura, J . Inorg. Nuclear Chem., 1974, 36, 1605. M.Tsuhako, I. Motooka, and M. Kobayashi, Chem. Letters, 1974, 435. J. K. Fawcett, V. Kocman, and S. C. Nyburg, Acta Cryst., 1974, B30, 1979. M. Laugt, A . Durif, and C. Martin, J . Appl. Cryst., 1974, 7, 448. M. Laugt and A. Durif, Acta Cryst., 1974, B30, 2118.

380

Inorganic Chemistry of the Main -group Elements

the In addition to Cs21nP301,,8H20,basic salts are formed from aqueous solutions of InC1, and CssP3010,5s3 and complex formation between tripolyphosphate and rare-earth ions has been followed potentiometrially.^^, Guanidinium polyphosphates are the products when ammonium dihydrogen phosphate is heated with di~yandiarnide,”~ and, as expected, increasing the temperature gives larger amounts of the more highly condensed species, with 3-10 phosphate units. New heteroionic-type compounds have been discovered during work on the ~ 0 3 - W 0 3 - M o 0 3 ternary Single-crystal measurements show the usual helical chain of condensed phosphate groups in the structures of Nd(PO,),,”’ Yb(Po3)3,’58 K2Cu(P03)4,5s9 and K2Co(P03),.559In the ultraphosphates NdP501,5s7and SmP,014,560 two such polyphosphate chains are cross-linked by PO, tetrahedra, giving PsO1, as the repeating unit. The distribution of phosphate units in sodium sulphato-phosphate glasses can be determined by 31Pn.m.r. The structure of Si,O(PO,), is isotypic with the germanium analogue and consists of isolated Si06 and Si,07 groups linked by PO, tetrahedra into a three -dimensional net. 562 In the antimony phosphate SbO(H2P04),H20 there are infinite layers of PO, and SbO, tetrahedra sharing corners, with water molecules between the layers.s63There are linked PO, tetrahedra and Ti06 octrahedra in the structure of KTiOP0,,564and PO, and VO, groups in -VPO~Y

Phase Studies. The following systems have been investigated; formulae in square brackets are identified phases: Na3P04-Mg3(P04)2 [NaMg4(P04)3 and NaMgP04];566 Na2HP04-(NH&HP04-H20 [NaNH4HP04,4H20],567 KHtP04-N&H2P04-H20;568 KH2P04-CO(NH2)2-H20;568 NH4H2P04C O ( N H Z ) ~ - H Z OAg3P04-AgP03 ;~~~ [Ag4P207];570 LiP03-Ni(P0& [LiNi 552

Yu. B. Kirillov and K. I. Petrov, Russ. J . Inorg. Chem., 1973, 18, 964.

”’ G. V. Rodicheva, E. N. Deichman, I. V. Tananaev, and Zh. K. Shaidarbekova, Russ. J. Inorg. Chem., 1973, 18, 1352. M. M. Taqui Khan and P. R. Reddy. J. Inorg. Nuclear Chem., 1974, 36, 607. 5 5 5 E. Kobayashi, Bull. Chem. SOC.Japan, 1973, 46, 3795. 4 5 6 L. V. Semenyakova and I. G. Kokarovtseva, Russ. J. Inorg. Chem., 1973, 18, 1632. 557 H. Y.-P. Hong, Acta Cryst., 1974, B30, 468. 558 H. Y.-P. Hong, Acta Cryst., 1974, B30, 1857. 5 s q M. Laugt, I. Tordjman, G. Bassi, and J. C. Guitel, Acta Cryst., 1974, B30, 1100. 5h0 D. Tranqui, M. Bagieu, and A. Durif, Acta Cryst., 1974, B30, 1751. F. G. Remy and J. R. Van Wazer, J. Inorg. Nuclear Chem., 1974, 36, 1905. 5 6 2 H. Mayer, Monatsh., 1974, 105, 46. s63 C. Sarnstrand, Acta Chem. Scand. (A), 1974, 28, 275. 564 I. Tordjman, R. Masse, and J. C. Guitel, Z. Krist., 1974, 139, 103. ”‘ B. Jordan and C. Calvo, Canad. J. Chem., 1973, 51, 2621. ”‘ J. Majling, Chem. Zvesti, 1973, 27, 732. 5h7 R. F. Platford, J. Chem. and Eng. Data, 1974, 19, 166 568 A. G. Bergman, A. A. Gladkovksaya, and R. A. Galushkina, Russ. J. lnorg. Chem., 1973,18, 1047. 5h‘) R. Kummel and R. Fahsl, Z. anorg. Chem., 1973, 402, 305. 570 R. K. Osterheld and T. J. Mozer, J. Inorg. Nuclear Chem., 1973, 35, 3463 554

381

Elements of Group V

ICP03-NiP03 [KNi(PO& and K2Ni(P03)4];571 NaP03-KP03 [NazKP309];572 Na4P207-M&P20,;:73 Na,P207-Zn2P,07;573 RbP03-CU(P03)2[ C U ~ R ~ ~KPO3-Al2O3 P ~ ~ ~ ~ [&f%(p@10)3, ] ; ~ ~ ~ K6&(p207)3, and K3A12(P04)3];’7’T1P03-Cu(P03)2 [CUTI(PO~)~ and C U ~ T ~ ~ P ~ ~ ~ ~ ] . ~

Powder Diffraction Data. Data for the following compounds are available: ’~ NaMP04,9H,0 (M = Sr M,PO, (M = K, Rb, or C S ) ; ~Na4Mg(P04)2,2H,0;578 or Ba);”” MTh,(PO,), (M = Cu or Tl);”’ CO~(PO~),;~”’ ammonium tri- and tetra-polypho~phates.’”~ Bonds to Sulphur or Selenium.- Values for the dissociation energies (DE) of the diatomic species PS, PSe, and m e , determined by Knudsen-cell mass Some 31P spectrometry, are 438, 360, and 294 kJ mol-’, re~pectively.~’~ n.m.r. data for P4S3in the polycrystalline and in a nematic phase are now a ~ a i l a b l e . ’ Displacement ~~ of one carbon monoxide group from Mo(CO)~occurs on reaction with P4S3,giving (84),586and crystal data show

co OC\

’co

I /Co

Mo

I ‘co

that, with the exception of the P-S bonds to the attached phosphorus atoms, the dimensions of the cage change little. Carbon disulphide inserts rapidly into -the P-N bond of N-dimethylaminophosphines containing phosphorus-sulphur bonds to give thiocarbamoyl derivatives such as Me,NC(S)SPR’R’, but similar reactions with 571 s72

573

57J 575 576 577 578 579

580 581

582

583

584

585 s86

P. de Pontcharra and A . Durif, Compt. rend., 1974, 278, C, 175. C. Cavero-Ghersi and A. Durif, Compt. rend., 1974, 278, C, 459. P. Fellner and J. Majling, Chem. Zuesti, 1973, 27, 728. M. Laugt, Compt. rend., 1974, 278, C, 1197. S. I. Berul’ and N. I. Grishina, Russ. J. Jnorg. Chem., 1973, 18, 1334. M. Laugt, Compt. rend., 1974, 278, C, 1497. R. Hoppe and H. M. Seyfert, Z . Naturforsch., 1973, 28b, 507. A. Ghorbel, F. d’Yvoire, and C. Dorkmieux-Morin, Bull. SOC.chim. France, 1974, 1239. E. Banks and R. Chianelli, J. Appl. Cryst., 1974, 7 , 301. M. Laugt, J. Appl. Crysf., 1973, 6, 299. A. G. Nord; Acta Chem. Scand.(A), 1974, 28, 150. K. R. Waerstad and G. H. McClellan, J. Appl. Cryst., 1974, 7 , 404. J. Drowart, C. E. Myers, R. Szwarc, A. van der Auwera-Mahieu, and 0. M. Uy, High Temp. Sci., 1973, 5, 482. E. R. Andrew, W. S. Hinshaw, and A. Jasinski, Chem. Phys. Letters, 1974, 24, 399; E. R. Andrew, W. S. Hinshaw, M. G. Hutchins, and A. Jasinski, ibid., 1974, 27, 96. N. Zumbulyadis and B. P. Dailey, Chem. Phys. Letters, 1974, 26, 273. A. W. Cordes, R. D . Joyner, R. D . Shores, and E. D. Dill, Inorg. Chem., 1974, 13, 132.

3 82

Inorganic Chemistry of the Main- group Elements

carbon dioxide do not occur.s87Full structural details are available for the trisulphide (85).s’’ A previously unknown class of compounds, SS-dialkyl

hydrogen phosphorodithioites (RS),POH, can be prepared by hydrolysis of the corresponding chloride, but purification by distillation is not p~ssible.”~ y-Irradiation of PSCI, generates SPCI;, SPCl,, and SPCl: radicals, but the corresponding bromide gives SPBr; and SPBr2.590 Photoelectron spectra have been reported for SPCI3-,(NMe2),, showing that the first ionization potentials involve electrons significantly localized on ~ulphur.~” Assignments have been given for the vibrational spectra of [P(SMe),]+SbCl;.sg2 The dithiophosphinic acids in the series (C,H,,+,),P(S)SH, where n = 2-18, and their zinc salts can be rapidly detected and separated by thin-layer chromat~graphy.’’~ Preparative methods have been devised for two new phosphonothioic dichlorides RP(S)C12, where R = 2-chlorocyclohexyl and 1-cyclohexen-1yl,594and for the pentafluorophenyl derivatives C,F,P(S)X,, R(C,F5)P(S)X, and (C,F5)2P(S)X.’9’ Compounds with the general formula [R,P(X)],Y, where X and Y = O or S, have been prepared for detailed n.m.r. Me,P(S)Br

2R,P(S)Br

+ +

Me2P(S)ONa 2NaSH

-

--+

[Me,P(S)I20 + NaBr

[R,P(S)],S

+

2NaBr

+

H,S

(18) (19)

studies, and among the reactions used are those in equations (18) and (19).’, The P-S-P bridge in thiodiphenylphosphinic anhydride (86) is 5x7 588

5x9

590

591

592 593

594

5y5

5 96

H. Boudjebel, H. GonGalves, and F. Mathis, Bull. SOC.chim. France, 1974, 1671. M. G . Newton, H. C . Brown, C. J . Finder, J . B. Robert, J . Martin, and D. Tranqui, J.C.S. Chem. Comm., 1974, 455. S. F. Sorokina, A. I. Zavalishina, and E. E. Nifant’ev, J . Gen. Chem. (U.S.S.R.), 1973, 43, 748. S. P. Mishra, K. V. S. Rao, and M. C. R. Symons, J. Phys. Chem., 1974, 78, 576. V. I. Vovna, S. N. Lopatin, R. Pettsold, F. I. Vilesov, and M. E. Akopya, Optics and Spectroscopy, 1973, 34, 501. H. Stoll and J. Goubeau, 2. anorg. Chem., 1974, 406, 307. J. Auvray and A. Lamotte, Bull. SOC.chim. France, 1974, 407. A. F. Grapov, V. A. Kozlov, E. I. Babkina, and N. N . Mel’nikov, J . Gen. Chem. (U.S.S.R.), 1973, 43, 1904. M. Fild and T. Stankiewicz, Z . Naturforsch., 1974, 29b, 206. G. Hagele, W. Kuchen, and H. Steinberger, Z . Naturforsch., 1974, 29b, 349.

EEements of Group V

383

broken when reaction occurs with bis(dimethy1amino)sulphane [see equation (2O)],”’ and bridge cleavage also occurs when the disulphide (RO),P(S)SSP(S)(OR), reacts with either primary or phenylhydra~ine.’~’ With the former the products are N-alkyl-S -phosphinohydrosulphamines (RO),P(S)SNHR, but the latter gives the salts [PhNHNHJ[(RO),PS,]-. The boron trihalide complexes with a number of phosphine sulphides and selenides can be isolated for the chloride, bromide, or iodide but, consistent with its reduced Lewis acidity, the trifluoride does not react.600Alkyldithiophosphonir, acids give tin, lead, and mercury derivatives such as Me,SnSP(S)FEt, Pb[SP(S)FMe],, and MeHgSP(S)FMe, which are monomeric in solution, and there is n.m.r. evidence for a bidentate phosphonate group in the tin compound.6o1 Vanadyl chelates of alkoxy-ethyl and alkoxy-phenyldithiophosphonates (87) have been synthesized and e.s.r. measurements

(87) R‘= Et or Ph, RZ= Me, Et, Pr, etc.

carried out? while magnetic measurements together with i.r. and electronic spectra are reported for vanadyl and uranyl complexes of a number of substituted diaryldithiophosphinic G.1.c. on a glass microbead column is a useful separation method for metal dialkyldithiophosphates.604 An X-ray structure of one of the monoclinic modifications of tin hexathiohypodiphosphate, Sn,P,S,, shows P& groups with close to 3m symmetry connected into a three-dimensional net by tin The P-P distance is 2.202 A and P-S distances range between 2.015 and 2.035 A. The thiophosphates Na3POS3and NaBaP0,S,8H20 are isotypic with the corresponding thioarsenates.606 The red phosphorus-P,Se3 system has been examined and the selenide shown to exist in three allotropic Insertion of selenium into the P-P bond of (CF3)2PP(CF3)2 occurs on heating at 100°C but reactions of 597 598

599

E. Fluck, G. Gonzalez, and H. Binder, 2.anorg. Chem., 1974, 406, 161. B. A. Khaskin, N. N. Mel’nikov, and N. A. Torgasheva, J. Gen. Chem. (U.S.S.R.), 1973, 43, 1901. B. A. Khaskin, N. A. Torgasheva, and N. N. Mel’nikov, J. Gen. Chem. (U.S.S.R.), 1973, 43,

2065. ‘00

602

603

‘04

‘06

607

P. M. Boorman and D. Potts, Canad. J. Chem., 1974, 52, 2016. H. W. Roesky, M. Dietl, and A. H. Norbury, Z. Naturforsch., 1973, 28b, 707. D. R. Lorenz, D. K. Johnson, H. J. Stoklosa, and J. R. Wasson, J. Inorg. Nuclear Chem., 1974, 36, 1184. R. N. Mukherjee, S. V. Shanbhag, M. S. Venkateshan, and M. D. Zingde, lndian J. Chem., 1974, 11, 1066. T. J. Cardwell and P. S. McDonough, Inorg. Nuclear Chem. Letters, 1974, 10, 283. G. Dittmar and H. Schafer, 2. Naturforsch., 1974, 29b, 312. M. Palazzi, Bull. SOC.chim. France, 1974, 42. Y. Monteil and H. Vincent, Canad. J . Chem., 1974, 52, 2190.

384

Inorganic Chemistry of the Main-group EZements the product [(CF,),P],Se with hydrogen chloride and the halogens, etc. give known phosphorus compounds with separation of selenium.6o8New phosphorus selenides RP(Se)F2 and RP(Se)FCI can be prepared by fluorination of the corresponding chlorides,60" and the monoselenophosp hinic acid Bu'PhP(Se)OH has been prepared by two independent routes and resolved into optical antipodes.610Two series of products, i.e. the isomeric thiono(selenolo) and thiolo(se1enono) derivatives, which are separable by column chromatography, result from reactions between potassium 00-diphenylphosphoroselenothioate and alkyl chloromethyl sulphides.61' Few instances of hydrogen bonding to selenium or tellurium are known, but this is indicated by shifts in the OH stretching mode of phenol in the presence of, for example, Bu,PSe or (Me,N),PTe."l2 1.r. spectra have been reported for metal complexes incorporating Ph,P(Se)Se, Ph,P(S)S, PhzP(Se)S,6'3and (PhO),P(Se)S ligand~.~'"

3 Arsenic Arsenic and Arsenides.-Appearance potentials for the negative ions As-, As;, and As;, formed from As, by dissociative resonance capture, have been measured, giving values of the standard heats of formation."' New ternary arsenides, including RhMAs (M=Ti, V, Cr, Fe, or Ni), RuMAs (M = Mn or Cr), and PdMAs (M =Ti or Cr), have been prepared from elemental mixtures heated at 700-85O0C, and they have been assigned to structural types.616 Continuous phase transitions for CrAs, CoAs, and Mno.,Feo.lAsbetween the closely related MnP and NiAs structures have been detected by X-ray diffraction over an extended temperature range,617 and for the latter compound the transformation is either a second- or higher-order process.618The compounds CoM,, RIM3, and IrM3, where M = A s or Sb, belong to the skuttesudite structure type, and these new X-ray data have been compared with those for the isostructural p h o ~ p h i d e s .The ~ ~ ~absence of Zn-Zn bonds in the crystal structure of ZnAs, is notable, as these were expected, on the basis of the presumed 608

R. C. Dobbie and M. J. Hopkinson, J . Fluorine Chem., 1973, 3, 367. H. W. Roesky and W. Kloker, Z. Naturforsch., 1973, 28b, 697. 'lo B. Krawiecka, Z. Skrzypczyfiski, and J. Michalski, Phosphorus, 1973, 3, 177. 6 1 1 N. M. Vatamanyuk, V. V. Turkevich, N . 1. Gritsai, and A. P. Vas'kov, J. Gen. Chem. (U.S.S.R.),1973, 43, 1697. 612 R. R. Shagidullin, I. P. Lipatova, I. A. Nuretdinov, and S. A. Samartseva, Doklady Chem., 1973, 211, 694. '13 A. Miiller, V. V . Krishna Rao, and P. Christophliemk, J . Inorg. Nuclear Chern., 1974, 36, 474. 'I4 I. M. Cherernisina, L. A. Il'ina, and S. V, Larionov, Russ. J. Inorg. Chem., 1973, 18, 675. 6 1 5 S. L. Bennett, J. L. Margrave. J. L. Franklin, and J. E. Hudson, b. Chem. Phys., 1973, 59, 5814. 616 B. Deyris, J . Roy-Montreuil, A. Rouault, A. Krumbugel-Nylund, J.-P. Shateur, R. Fruchart, and A. Michel, Compt. rend., 1974, 278, C, 237. 6'7 K. Selte and A. Kjekshus, Acta Chem. Scand., 1973,'27, 3195. K. Selte, A. Kjekshus, and A. F. Andresen, Acta Chem. Scand., 1973, 27, 3607. 6'9 A. Kjekshus and T. Rakke, Acta Chem. Scand. (A), 1974, 28, 99. '09

Elements of Group V

385

isomorphism with ZnP2.620 The structure contains two types of zinc and four types of arsenic sites, but all involve tetrahedral co-ordination. A new cationic complex containing Hg-As bonds has been synthesized following equation (21). The products with X =NO;, PF;, or BF, are stable MeHgX

+ 3MeHgOBu‘ + ASH,

-+

+

[As(HgMe),]X

3Bu‘OH (21)

in air and probably have a tetrahedral structure.621 Low yields of Ag(HgMe), could be obtained by modifying the conditions but it was not possible to obtain the antimony analogues.

Bonds to Carbon.-A novel cyclo-triarsane derivative (88), in which the substituents are constrained into all cis positions, can be obtained by Me

I

/c\

CH,

\

I A+A~

CH,

CH21

‘As/

(88)

heating MeC(CH2As12),with sodium in THF.622Some 7 5 An.q.r. ~ measurements are in good agreement with the known structures of (PhAS), and (C6F,As)6,623 while for (89) and (90), of unknown structures, the results point to the presence of a diad axis in the former and the possibility of three different forms for (90) depending on the crystallization method. A ladder Ph- As- As-Ph

I

I

CF,-CC--L-CF,

FC

AS-AS-C6F,

6 - ~

I

F,C-C=C-CF,

polymer of high molecular weight that has recently been synthesized has semiconductor properties, and it is based on the stacking of MeAs-AsMe Preparation is either by HI elimination from mixtures of MeAsHz and MeAsI, or by cleavage of ( M ~ A Swith ) ~ a trace of MeAsC1,. A series of monocyclopentadienyl-arsines (91) with fluxional u -bonded structures can be prepared from halogeno-arsines and either cyclopentadienyltrimethylsilane or lithium ~yclopentadienide.~~’ Vibrational spectra of (PhCH,),MX,, where M = A s or Sb and X = F or C1, are in accord with 620 621

622 623 624

625

M. E. Fleet, Acta Cryst., 1974, B30, 122. D. Breitinger and G. P. Arnold, Inorg. Nuclear Chem. Letters, 1974, 10, 517. J. Ellermann and H. Schossner, Angew. Chem. Intenat. Edn., 1974, 13, 601. T. J. Bastow and P. S. Elmes, Austral. J. Chem., 1974, 27, 413. A . L. Rheingold, J. E. Lewis, and J. M. Bellama, Inorg. Chem., 1973, 12, 2845. P. Jutzi and M. Kuhn, Chem. Ber., 1974, 107, 1228.

386

Inorganic Chemistry of the Main- group Elements

R'

(91) R '

= R'= F, CI, Br, or

Me

slightly distorted trigonal-bipyrarnidal structures,626and i.r. and Raman data for Me,As, obtained by a low-temperature reaction between Me,AsCl, and methyl-lithium, have also been interpreted on the basis of trigonal-bipyramidal ge~metry.~"Similar data for Ph,As and Ph,Sb indicate that the solid-state structures, i.e. trigonal-bipyramidal and square-pyramidal respectively, are retained in

Bonds to Halogens.-Reactions between AsF, and the negative ions formed mass spectrometrically lead to AsF; as the predominant secondary ion, whereas in AsF,, both AsF; and AsF; are formed.629A series of new fluoroarsinic acid esters F,As(OR),+,, with n = 1 or 2 and R = methyl to hexyl, result from either alcoholysis of the trifluoride or redistribution reactions between mixtures of the trifluoride and trialkoxide .630 The product identities were confirmed by "F and 'H n.m.r. spectroscopy. An accurate redetermination of the structure of KAsF, confirms the space group as R; and shows a nearly perfect octahedron of fluorine atoms about arsenic (As-F 1.72 A)."' Anions with C, symmetry are found in the structures of the isomorphous compounds Rb,(As,F,,O),H, 0 and K,(As,F,,O),H,O;6" bonds to the bridging oxygen are 1.77 and 1.72 A and the AsOAs angle is 136.5". In the doubly oxygen bridged anion [As2F,02]*-, on the other hand, the structure is centrosymmetric, with D,, symmetry. Structural parameters, shown in Figure 13, point to the shortness of the As * * As distance and the 96" angles at the bridging oxygen atoms as being significant The hexafluoroarsenate ion is well known as stabilizing unusual cations, and in the period covered in this Report the following compounds have been investigated: NF,'AsF; (thermal decomposition),hi OSF,Cl+AsF, (preparacrystal s t r u c t ~ r e ~0SF:AsF; ~~), tion, also PF;, SbK, and Sb,F;, (crystal ~tructure),6~' C1F;AsF; (vibrational data),h38ClOF,'AsF; (preparation and vibrational data, also Sb, Bi, V, Nb, and Ta analogues),639K r F *

"' L. Vernonck

and G. P. van der Kelen, Spectrochirii. Acta, 1973, 29A, 1675.

''' K.-H. Mitschke and H. Schmidbaur, Chem. Ber.. 1973, 106, 3645. "' G. L. Kok, Spectrochim. Acta, 1974. M A , 961. '*'

63"

631

632 633 634

63s 636

h37 63'

639

T. C. Rhyne and J. G. Dillard, Inorg. Chem., 1974, 13, 322. F. Kober and W. J. Ruhl, J. Fluorine Chem., 1974, 4, 65. G. Gafner and G. J. Kruger, Acta Cryst., 1974, B30, 250. W. Haase, Acta Cryst., 1974, B30, 1722. W. Haasc, Chem. Ber., 1974, 107, 1009. 1. J. Solomons, J. N . Keith, and A. Snelson, J. Fluorine Chern., 1972. 2, 129. C . Lau and J. Passmore, J.C.S. Dalton, 1973, 2528. R. F. Dunphy, C . Lau, and J. Passmore, J.C.S. Dalton, 1973, 2533. C.Lau, H. Lynton, J. Passmore, and P.-Y. S e w , J.C.S. Dalton, 1973, 2535. K. 0. Christe and W. Sawodny, Inorg. Chem., 1973, 12, 2879. R. Bougon, T. Bui Huy, A. Cadet, P. Charpin, and R. Rousson, Inorg. Chem., 1974,13, 690.

Elements of Group V

387

Figure 13 The structure of the [As2F8O2]2-ion in CsAszFsO;! (Reproduced by permission from Chem. Ber., 1974, 107, 1009) AsFi, Kr,FSAsF; ("F n.m.r. and Raman spectra, also SbF; XeFAsF;, Xe,SAsF$ (Raman [(FXe),SO3F]'AsF$ (preparation, "F n.m.r. and Raman spectra).642 In addition to these, Gillespie and his co-workers have produced two new mercury cations by oxidation of the element with either AsF, or SbF, in liquid sulphur dioxide. The formulae ~;~~ results are Hgs(AsF,), or Hgs(SbzFI1)2643 and H & ( A s F ~ )crystallographic are available for each. During the initial stages of these oxidation reactions, the mercury is converted into a golden mass, which by crystallography can be formulated as Hg2.86AsF6.645 The structure consists of an array of octahedral AsF; ions with the fluorine atoms occupying three quartets of the points of a cubic-close-packed lattice, together with infinite chains of mercury atoms with bonds shorter than those in the metal running along the a and b directions. A fluorosulphate ion transfer to AsF, occurs with chloryl fluorosulphate, giving C102[AsF,(S03F)],but an analogous antimony compound could not be prepared.646In this case the product was a mixture of C1O2(Sb2F,,)and SbF, (S0,F). The preparation of 1: 1 complexes of arsenic, antimony, and bismuth trihalides with dithio-oxamides has been r e p ~ r t e d . ~1.r. ~ ' spectra of the arsenic compounds point strongly to the probability of dimeric, octahedral structures, but with the two heavier Group V elements square-pyramidal structures have been suggested. Crystalline adducts 2MBr3,3dioxan, where 640 641

642 643

644 645

646 647

R. J. Gillespie and G. J. Schrobilgen, J.C.S. Chem. Comrn., 1974, 90. R. J. Gillespie and B. Landa, Inorg. Chem., 1974, 13, 1383. R.J. Gillespie and G. J. Schrobilgen, Inorg. Chem., 1974, 13, 1694. B. D. Cutforth, C. G. Davies, R. A. W. Dean, R. J. Gillespie, P. R. Ireland, and P. K. Ummat, Inorg. Chem., 1974, 13, 1343. B. D. Cutforth, R. J. Gillespie, and P. R. Ireland, J.C.S. Chem. Comm., 1973, 723. I. D. Brown, B. D. Cutforth, C. G . Davies, R. J. Gillespie, P. R. Ireland, and J. E. Vekris, Canad. J . Chem., 1974, 52, 791. P. A . Yeats and F. Aubke, J . Fluorine Chem., 1974, 4, 243. G. Peyronel, A . C. Fabretti, and G. C. Pellacini, Spectrochim. Acta, 1974, 30A, 1723.

388 Inorganic Chemistry of the Main -group Elements M = A s , Sb, or Bi, can be isolated, but cryoscopy indicates their complete dissociation in Solubility data for arsenic, antimony, and bismuth tribromides show regular solution behaviour in a number of organic absorption spectra of the corresponding iodides in the solid state have been ~ b t a i n e d . ~ " Refinement of the As-AsI, region of the arsenic-iodine diagram65'does not show the formation of AsJ, as was suggested by previous investigators. Bonds to Nitrogen.-An extensive series of bis(dimethy1arsino)amines RN(AsMe,), can be prepared from chloro- or iodo-dimethylarsine and the appropriate primary amine.652The As-N bonds in such compounds are markedly sensitive to protonic reagents, e.g. hydrogen halides, alcohols, thiols, but with tris(dimethy1amino)arsine this serves as a convenient route to a large number of esters and thi0este1-s.~~~ With Me,AsNMe,, 172-diols and with can give both mono- and di-esters depending on the mole hydroxymethylf errocene the product is CpFeC5H4CH~OAsMe2.6s5 An analogous di-ferrocene product is obtained with MeAs(NMe,),. Other secondary amine derivatives result from transamination reactions with Me2NAsF,, and the operation of steric and mechanistic effects in these systems has been c o n ~ i d e r e d . ~Transamination '~ with primary amines is not as clear-cut, and polymeric species, probably of the form (RN=AsF),, are the products. Ammonolysis of chlorodimethylarsine gives the substituted ammonium chloride [Me,AsNH,]Cl, while in admixture with chloramine the product has the empirical formula Me4As2N2HCL6"The latter also results if tetramethyldiarsine is the starting material. Corresponding reactions of EtzAsCl with ammonia and chloramine give (Et,As),N and Et,As,N,HCl, respectively, while with tetraphenyldiarsine, chloramination produces the hydrochloride of the trimeric arsazene, (Ph,AsN),,HCl. Mass spectral data for all the compounds have been discussed and the results of a single-crystal structure determination on (Ph,AsN), also reported. The As,N, ring is slightly puckered but all the As-N distances are equal (1.758 A). Methoxy derivatives of such arsenic-nitrogen cyclic systems, which are analogues of the better known cyclo-phosphazenes, have been obtained from the decomposition of NH4[As(OMe),]."'" The bulk of the product by mass spectrometric analysis is the trimer, but [AsN(OM~)~],, can also be detected. 6JH

R. C . Mahebhwari, S. K. Suri, and V. Ramakrishna, lndian J. Chem.. 1973. 11, 1196. R. C. Maheshwari, S . K. Suri, and V. Ramakrishna, J . Inorg. Nuclear Chem., 1974, 36, 1809. B. Mishra and V. Ramakrishna, Indian J. Chem., 1973. 11, 790. A. P. Chernov, S. A. Dembovskii, and A. F. Borisenkova, Russ. J. Inorg. Chem., 1973, 18, 1530. 652 F. Koher, Z . anorg. Chern., 1973, 301, 243. "' F. Kober and W. J. Ruhl, Z . anorg. Chem.. 1974, 403, 56. "' F. Kober and W. J. Riihl, Z . anorg. Chem., 1974, 406, 52. 6 s 5 F. Kober, Z . Naturforsch., 1974, 29b, 358. 656 F. Kober and 0. Adler, J. Fluorine Chem., 1974, 4, 73. 657 L. K. Krannich, U. Thewalt, W. J. Cook, S. R. Jain, and H. H. Sisler, Inorg. Chem., 1973, 12, 2304. H. Preiss and D. Hass, Z . anorg. Chem., 1974, 404, 190. h4y hS0

Elements of Group V 389 Bonds to Oxygen.-Alcohol groups can be displaced from triethoxyarsine by oximes or diethylhydroxylamine in a stepwise manner to give the Two new 1,3,2-dioxa-arsolans (92) products (EtO)3-nAs(ON=CR1Rz),,.659 result when tris(dimethy1amino)arsine and either ethylene glycol or pinacol react, and further reaction of these compounds with a -hydroxy-acids leads

0

Me

NCA,

R1,

As-OCR'R'COO-

I

H2kMe2

R"co ''

(94) R = C l , X = O o r S

R=Ph,X=OorS

(93)

to displacement of both the glycol and amine group, giving (93).'" Detailed analysis of the proton spectra of similar cyclic arsenates (94) leads to coupling-constant and chemical-shift data661and shows the presence of both cis- and trans -isomers. Ring opening in oxathioarsolans ( 9 3 , noted here for

the first time, can be brought about by monothioglycol, giving PhAs(SCH2CHzOH)z.66z This compound can also be prepared from PhAs(OMe), and the thioglycol following the general method in equation (22).'" R',As(XR*),.., R' = Et or Ph X = O or S R' = Me or Et

+

( 3 - n)HSCH2CH20H

--+

(3 - n)R'XH

+

R',As(SCH,CH,OH),_,

(22)

Complex formation between arsenic or antimony(m) oxide and selenium trioxide gives the adducts Mz0,,3Se0, but the corresponding pentoxides do R. C. Mehrotra, A. K. Rai, and R. Bohra, Synth. React. Inorg. Metal-Org. Chem., 1974, 4, 167. P. Maroni, Y. Madaule, and J.-G. Wolf, Compt. rend., 1974, 278, C, 191. 6 6 1 D. W. Aksnes and 0. Vikane, Acta Chem. Scand., 1973, 27, 2135. 662 N. A . Chadaeva, K. A. Mamakov, and G. Kh. Kamai, J . Gen. Chem. (U.S.S.R.), 1973, 43, 821. 663 N. A . Chadaeva, K. A. Mamakov, R. R. Shagidullin, and G. Kh. Kamai, J . Gen. Chem. (U.S.S.R.), 1973, 43, 825. 65y

3 90

Inorganic Chemistry of the Main-group Elements

not The arsenic(II1) complex forms a conducting solution in fluorosulphuric acid which may contain the solvated AsO' ion, but a polymeric structure (96) is considered more likely for the species in the

(96)

solid state. For the antimony compound the formula is given as Sb,(SeO,),. Kinetic studies have been carried out on the oxidation of arsenic(rI1) by Tl"' in perchloric and by CrVx.665b Attempts to prepare alkoxyarsonium salts such as [Ph,AsOCH,C(O)OR]X from triphenylarsine oxide and either halogenoacetic esters, chloroacetone, or chloroacetonitrile gave only (Ph3AsOH)X for X = C1 or Br and (Ph,AsO)?HI when iodides were used.""" Mass spectrometric measurements on As(OMe),, OAs(OMe),, As(OMe),, and a variety of similar species generally show a molecular ion of low intensity, which fragments by a simple cleavage reaction.667Further details of the fragmentation have been discussed. The presence of a four-membered ring (97) in compounds

(97)

with the formula A s , O ( O M ~ ) ~ N is R indicated by 'H n.m.r. and massspectrometric data.""" Detailed vibrational spectra and normal-co-ordinate analyses are now available for M~,As(O)OH,~"'~"~" MeAs(O)(OH),,""' MeAsO:-,""' M ~ A S ( O ) ( O M ~ ) , , ~ ~Me,As(O)(OMe),"" '~~" and (Me0)3As0,671 etc. Spirocyclic structures (98) have been assigned to the esters produced from glycols and aryl- or alkyl-arsonic 664

R. C. Paul, R. D. Sharma, S. Singh, and K. C . Malhotra, Indian J. Chem., 1973, 11, 1174.

"' ( a ) P. D. Sharma and Y . K. Gupta, Austral. J. Chem., 1973, 26, 2115; ( b ) K. K. Sen Supta h6h 667 h68 669 670

671 672

and J. K. Chakladar, J.C.S. Dalton, 1974, 222. B. E. Abalonin, Yu. F. Gatilov, and Z . M. Izrnailov, J. Gen. Chem. (U.S.S.R.),1974, 44, 145. H. Preiss, Z . anorg. Chem., 1974, 404, 175. H. Preiss and H. Jancke, 2. anorg. Chem., 1974, 404, 199. H.-V. Grundler, H.-D. Schumann, and E. Steger, J. Mol. Structure, 1974, 21, 149. F. K. Vansant, B. J. van der Veken, and M. A. Kerrnan, Spectrochim. Acta, 1974, 30A, 69. F. K. Vansant and B. J. van der Veken, J. Mol. Structure, 1974, 22, 273. V. S. Garnayurova, V. V. Kuz'rnin, B. D. Chernokal'skii, and R. R. Shagidullin, J. Gen. Chem. (U.S.S.R.),1973. 43, 1921.

Elements of Group V

391

Oxygen exchange between arsenate and water is dependent on pH, with the reaction is an overall activation energy of 13.2 kcal mol-' at pH 7.51 catalysed by arsenious acid, probably through rapid condensation of AS"' and As" species to give an anion of mixed oxidation state such as H,AszO;.673b Exchange of oxygen between Na2HAs0, and NaH,AsO, and crystal water has also been examined during hydration and dehydration Only one compound, NaMAs04,9H20, occurs in the Na,AsO,-M,(As04),-H20 system, where M = Sr or Ba;674ain the corresponding potassium arsenate systems the products are KMAs0,,8H20 but when M = C a , both octa- and hepta-hydrates are formed.674bX-Ray data have been reported for C ~ , ( H A S O ~ ) ~ ( A S O ~ ()g~~, t~rH i n~i tOe ) ~ and ~ ' compounds in the series N ~ , M H , - , ( A s O ~ ) ~ , ~ H where ~ O , M = A1 or Fe and 0.6 < x < 2.h76Solid phases produced in the Na,0-M20,-As,05-H20 system with M = Al or Fe depend on the exact preparative method used, and species such as NaAlH,(AsO,),,H,O, NasA1,H7(As0,)6,2H20, and N ~ , A I ~ ( A s O , )etc. ~ , result in the aluminium case .677 A series of stoicheiometric dihydrated orthoarsenates, i.e. MAs04,2H20 and a new where M = A l , Ga, Cry or Fe, with the scordite where M = Fe or Cr, have been described.679 family of arsenates M2As401Z, The latter result by heating M(H,As04),nH,0 to 800 "C and are considered to contain arsenic in both the +3 and +5 oxidation states. Their formulation as FeAs(AsO,),, for example, is supported by the isolation of an isotypic phosphor us compound Fe,AsP, 012, which is an orthophospha te. Dehydration of lanthanide arsenates LnAs04,2Hz0occurs at 140 "C to give amorphous materials, which crystallize on further heating in the range 400-500"C.680 Details of the preparation and i.r. and 'H n.m.r. spectra have been published for the following scandium arsenates: Sc(As0,),2H20, S C ( H ~ A ~ O ~ ) ~Sc,(H,As,O,),, ,~H~O, and SC(ASO,),,~~~ and the principal force 673

( a ) A. Okumura and N. Okazaki, Bull. Chem. SOC.Japan. 1973, 46, 2937; ( b ) A. Okumura, N. Yamamoto, and N. Okazaki, ibid., p. 3633; (c) A. Okumura and N. Okazaki, ibid., p.

2981. (a) N. Ariguib-Kbir, R. Stahl-Brasse, and H. GuCrin, Bull. SOC.chim. France, 1974, 1221; ( b ) N. Ariguib-Kbir, R. Stahl-Brasse, and H. GuCrin, Cornpt. rend., 1974, 278, C,339. M. Catti and G. Ferraris, Acta Cryst., 1974, B30, 1789. 616 F. d'Yvoire and M. Screpel, Bull. SOC.chim. France, 1974, 1211. 677 M. Screpel, F. d'Yvoire, and H. GuCrin, Bull. SOC. chim. France, 1974, 1207. 678 M. Ronis and F. d'Yvoire, Bull. SOC. chim. France, 1974, 78. 679 F. d'Yvoire, M. Ronis, and H. GuCrin, Bull. SOC.chim. France, 1974, 1215. 680 L. E. Angapova and V. V. Serebrennikov, Russ. J. Inorg. Chem., 1973, 18, 901. L. N. Komissarova, G. Ya. Pushkina, I. V. P. Khrameeva, and E. G. Teterin, Russ. J. Inorg. Chem., 1973, 18, 1225.

674

67s

392 Inorganic Chemistry of the Main-group Elements constants for the As,O;- ion have been estimated from the i.r. and Raman spectra of Sr,As,07 and Ba2As20,.682 Close similarity to the olivine structure is revealed by an X-ray study on C o 7 0 A ~ 3 6 0one 1 6 7of the compounds formed in the CoO-As,Os system.6R' The oxygen atoms are in hexagonal close packing, with the cobalt and arsenic occupying respectively the octahedral and tetrahedral sites. Complete occupancy of each site would lead to the composition Co8As4OI6. The regions of stability with respect to acid for the molybdo-arsenic heteropolyanions have been defined684and two new series of such acids with Mo :As ratios of 3 : 1, i.e. AszMo60:; and As,Mo,~O~;,have been isolated and fully identified.68s Bonds to Sulphur or Selenium.- Arsenic, antimony, and bismuth trichlorides react with bis(2-mercaptoethyl) sulphide, liberating hydrogen chloride and forming the cyclic compounds (99).'" Complete spectroscopic data

/

CH2--CHI-S

\

S'

\('H

2-C'H

2-S

have been measured for the and structures determined for the arsenic688and antimony ones.689In each case the eight-membered ring has a S interactions distorted boat conformation with strong transannular M (2.72 and 2.83 A, respectively, for M =As or Sb). In this way a pseudotrigonal-bipyramidal arrangement around the Group V element is achieved. Vibrational assignments from i.r. and Raman data have been proposed for and for Me,AsS and Me,AsSe.6y1 *

*

-

's-s' Arsenic tris(dialky1dithiocarbamates) show a wide range of 7 5 An.q.r. ~ signals merely on changing the alkyl group and, as all the compounds E. J . Baran, J. C. Pedregosa, and P. J. Aymonino, J. Mol. Structure, 1974, 22, 377. N. Krishnamachari and C. Calvo, Canad. J. Chem.. 1974, 52, 46. h84 R. Contant, B d l . SOC.chim. France, 1973, 3277. P. Souchay and R. Contant, Bull. SOC. chim. France, 1973, 3287. "' R. Engler, Z. anorg. Chem., 1974, 406, 74. '*' R. Engler, Z . anorg. Chem., 1974, 407, 35. M. Drager, Chem. Ber., 1974, 107, 2601. '*') M. Drager and R. Engler, Z . anorg. Chem., 1974, 405, 183. 69" K . Volka, P. Adamek, H. Schulze, and H. J. Barber, J. Mol. Structure, 1974, 21, 457. "" F. L. Kolar, R. A . Zingaro, and J. Laane, J. Mol. Structure, 1973, 18, 319. h82 hX3

Elements of Group V

393

contain arsenic in six-fold co-ordination, the changes are attributed to changes in the SASS angle.692The mass spectrometric behaviour of these compounds and the antimony and bismuth analogues has been and Manoussakis et al. have obtained the corresponding diselenocarbamate complexes from the reaction of the trichloride with a secondary amine and carbon diselenide .694 The thioarsinic acids [Ph,AsOS]H, [(PhCH2)2AsOS]H, and [(PhCH2)2AsS2]H have been described for the first time and used as ligands with transition Hydrogen sulphide at 400 "C converts lanthanide arsenates into trithioarsenates (AsOS:-) for the earlier lanthanides but to the dithio-analogues (AsO,S:-) with the elements from europium to lutetium.696 The compound Pb2&1& (jordanite) has a distorted PbS-type structure, with trigonal-pyramidal co-ordination by sulphur about the arsenic.697 The structure of As4Se4 is similar to that of realgar, with a square of selenium atoms bisecting a distorted tetrahedron of arsenic Princi2.384(5); As-As pal parameters of this cage molecule are: As-Se 2.566(8)A; LAsSeAs 98.1(3)"; LSeAsSe 94.2(3)".

4 Antimony Antimony and Antimonides.- Antimony metal and lithium nitride react at 430 "C to give a new binary compound Li,Sb, which is isotypic with Fe,P.699 Ca,Sb and Ca,Bi are i ~ o t y p i c and , ~ ~full structure determinations have been carried out on c~-Mg,Sb,,~~' Ca5Sb3,702and Sr5Sb,.703In the latter the structural unit is the SbSr, unit, in which the strontium atoms are arranged at the corners of a very distorted tetrakaidecahedron. X-Ray data suggest filled NiAs structures for the new compounds CaCuSb, SrCuSb, and their bismuth analogues, which are prepared from the elements at 1400 "C.'" Sharpening of I2'Sb Mossbauer spectra can be achieved in some cases by Fourier-transform methods, and this approach has been tested on data for CoSb, and Feo5Nio,5Sb3.705 Bonds to Carbon or Nitrogen.- The preparation of dialkoxy- and diphenoxy-stibines from methyldibromostibine and the sodium salts of 692 h93

694 695

696 697 698

699 700 7"1

702

' 0 3 704 '05

T. J. Bastow and H. J. Whitfield, J . Inorg. Nuclear Chem., 1974, 36, 97. G. E. Manoussakis, E. D. Micromastoras, and C. A. Tsipis, Z. anorg. Chem., 1974,403, 87. G. E. Manoussakis, C. A. Tsipis, and A. G. Christophides, Inorg. Chem., 1973, 12, 3015. A. Muller, P. Werle, P. Christophliemk, and I. Tossidis, Chem. Ber., 1973, 106, 3601. L. E. Angapova and V. V. Serebrennikov, Russ.J. Inorg. Chem., 1973, 18, 1213. T. Ito and W. Nowacki, Z. Krist., 1974, 139, 161. P. Goldstein and A. Paton, Acta Cryst., 1974, B30, 915. R. GCrardin and J. Aubry, Compt. rend., 1974, 278, C, 1097. B. Eisenmann and H. Schafer, Z. Naturforsch., 1974, 29b, 13. M. Martinez-Ripoll, A. Haase, and G. Brauer, Acta Cryst., 1974, B30, 2006. M. Martinez-Rip11 and G. Brauer, Acta Crysf., 1974, B30, 1083. M. Martinez-Ripoll and G. Brauer, Acta Cryst., 1973, B29, 2717. B. Eisenmann, G. Cordier, and H. Schafer, Z. Naturforsch., 1974, 29b, 457. A. Kjekshus and D. G. Nicholson, Acta Chem. Scand. (A), 1974, 28, 469.

3 94

Inorganic Chemistry of the Main -group Elements alcohols or phenols proceeds readily;706 the diethoxy-derivative proved useful as a starting material for ligand-exchange reactions with thiols, 1,2-diols, and 1,2-dithiols. An investigation of the structure of Ph,SbOSbPh, is of interest as Mossbauer data show two antimony peaks, but recent X-ray results show the presence of only one kind of antimony atom.'" The Sb-0 and Sb-C distances are 1.97 and 2.15 A, respectively, and as the CSbC and CSbO angles are only slightly greater than 90" it is concluded that the antimony lone pairs are accommodated in the s-orbitals. Mossbauer data at 80 K have been reported for compounds with the following formulae: R3SbX2, R,SbX,, R,SbX, and R,Sb.7"8 Organometallic reagents show promise as extractants for halogens, in particular fluorine, and a range of some 16 antimony derivatives has been Two distinct paths are followed in the decomposition of bisin~estigated.~'~ (tripheny1bromo)antimonyl peroxide, P h,BrS bOOSbBrPh,, in chloro benzene at 45 "C;"" the first involves liberation of oxygen and formation of Ph,BrSbOSbBrPh, but in the second, following heterolytic cleavage of the peroxy linkage, there is transfer of a phenyl group from antimony to oxygen. Five-co-ordination to both antimony atoms is found in the structure of the oxygen-bridged compound (Ph,SbN3)20,711 but in (Ph,Sb),CO, there is antimony in both five- and six-fold c o - ~ r d i n a t i o n .In ~ ~ the ~ azide, the bridging oxygen atom and the azido-group occupy axial positions in a slightly distorted trigonal-bipyramidal arrangement. The Sb-0 distance is 1.985(3) A and the bridge angle is 139.8(4)". In the second structure, shown in Figure 14, the carbonate group is bidentate to one antimony atom (Sb-0 2.185 and 2.325 A), giving an octahedral arrangement, and unidentate to the second atom (Sb-0 2.257 A). An octahedral arrangement with trans methyl groups has been found for dimethyldibromo(acety1acetonato)antim~ny(v).~ The l ~ unusual square-pyramidal geometry of Ph,Sb is not found for the penta-p-tolyl analogue.?14In this case, the structure is the more usual trigonal bipyramid, but it is distorted, particularly at the equatorial CSbC angles. Two of these, 113" and 130", are markedly different from the expected 120" angles, suggesting that packing forces play an important role in determining the ground-state structure of solid R,Sb compounds. 706

707 708

7OY

"" 711

713 714

N. Baumann and M. Wieber, Z. anorg. Chem.. 1974, 408, 261. J. Bordner, B. C. Andrews, and G. G . Long, Cryst. Struct. Comm., 1974, 3, 53. S. E. Gukasyan, V. P. Gor'kov, P. N. Zaikin, and V. S. Shpinel, J . Struct. Chem. (U.S.S.R.), 1973, 14, 603. M. Benmalek, H. Chermette, C . Martelet, D. Sandino, and J. Tousset, J . Inorg. Nuclear Chem., 1974, 36, 1359, 1365. J. Dahlmann and K. Winsel, Z. Chem., 1974, 14, 232. G. Ferguson and D. R . Ridley, Acta Cryst., 1973, B29, 2221. G. Ferguson and D. M. Hawley, Acta Cryst., 1974, B30, 103. S. Uda, Y. Kai, N . Yasuoka, and N. Kasai, Cryst. Struct. Comm., 1974, 3, 257. C. Brabant, J. Hubert, and A. L. Beauchamp, Canad. J. Chem., 1973, 51, 2952.

395

Elements of Group V

n

Figure 14 The structure of (Ph4Sb)2C03 (Reproduced by permission from Acta Cryst., 1974, B30, 103) Thermal or photochemical methods can be used to prepare metal carbony1 complexes from Sb(NMe,),;71swith the Group VI hexacarbonyls, the products are formulated as Sb(NMe,),,M(CO),.

Bonds to Halogens.-Antimony (111) Compounds. Aqueous solutions of antimony(II1) fluoride give only one I9F n.m.r. signal, whose shift decreases with increasing con~enfration.’~~ Addition of either NH,F or KF causes a downfield shift, which reaches a minimum at a 1:l mole ratio, thus providing unambiguous evidence for the formation of the SbF; ion. The structure of the new antimony fluoride, Sb,,F,, or 6SbF,,SSbF,, which can be prepared by direct fluorination of the element, has a unit cell containing ’I5 716

A. Kiennernann and R. Kieffer, Compt. rend., 1974, 279, C, 355. Yu. A. Buslaev and V. V. Peshkov, Russ. J. Inorg. Chem., 1973, 18, 803.

396 Inorganic Chemistry of the Main - group Elements five SbFi anions and a section of a polymeric chain cation, Sb,F,,5+.717 Separate SbF: and Sb2F: units can be distinguished in the cation, and in the latter there is a linear fluorine bridge between the SbF, and SbF, units. X-Ray diffraction and vibrational data have been reported for a series of l9 antimonate(111) salts. te trafluoro -718 and pentafl~oro-~ Antimony(II1) halides form addition compounds with potassium ferrocyanide, either in the melt or in sulphur dioxide solution, to which the formulae K,[Fe(CNSbX,),] for X = F or C1 or &[Fe(CNSbX,),(CN),], for X=C1 or Br, are given.72oMossbauer data for a number of antimony(111) species show large quadrupole splittings, associated with stereochemical activity of the 5s electrons, only for SbFi, SbCl;, and SbzF;-.”’ New vapour-pressure data for antimony trichloride in the 360-428 K temperature range lead to the log(p/a tm) = (4.07 f0.64) - (2 183 f80)K/ T Weak complex formation between the trichloride or tribromide and hydrocarbons, ethers, or ketones causes little change in the electron distribution around the antimony atoms according to a Mossbauer inve~tigation.’~~ Stronger complexes, i.e. SbX3,2L and BiX3,3L, are formed, for X = C1 or Br and L = tetramethylene sulphoxide, which from vibrational data have respectively square-pyramidal and octahedral co-ordination around the Group V atom.72A The extent of interaction between SbCl, and acetonitrile has been assessed from the splitting of the v(C-N) band, which is interpreted in terms of the existence of both donor-acceptor and dipole-dipole complexes.725The formation of an SbC1,-cis -stilbene adduct is apparently important in the antimony-trichloride-inducedphotoisomerization of stilbene in the presence of oxygen,726and ‘*‘Sb,I2%b,and 3’Cl n.q.r. spectra are Radio-chlorine exnow available for the 1 : 1 complex SbC13,PhNH2.727 change between labelled SbCI, and hexachloropropene, CC12=CC1CCl,, occurs only at C-1 and C-3 in both dichloromethane solution and in the heterogeneous system at temperatures between 0 and 65 0C.728Labelling does occur at C - 2 , however, at 150°C; exchange is considered to involve carbenium in termed iates . 7’7 718

7’y

720

722

723

724

725

726

727 728

A. J. Edwards and D. R. Slim, J.C.S. Chem. Comm., 1971, 178. M. Mehrain, B. Ducourant, R. Fourcade, and G. Mascherpa, Bull. SOC.chim. France, 1974. 757. N. Habibi, B. Ducourant, R. Fourcade, and G. Mascherpa, Bull. Soc. chim. France, 1973, 21. H. G. Nadler, J. Pebler, and K. Dehnicke, Z. anorg. Chem.. 1974, 404, 230. J. G. Ballard, T. Birchall, J. B. Milne, and W. 1).Moffett, Canad. J . Chem., 1974,52, 2375. V. Piacente and G. Balducci, Rev. Roumaine Chim., 1973. 18, 2083. L. H. Bowen, K. A . Taylor, H. K . Chin, and G. G. Long. J . rnorg. Nuclear Chcm., 1971, 36, 101. P. B. Bertan and S. K. Madan, J. Inorg. Nuclear Chrm., 1974, 36, 983. Yu. P. Egorov, E. V. Ryltsev, and I. F. Tsymhal, Optics and Spectroscopy, 1974, 35, 165. G. N. Salaita, J. Inorg. Nuclear Chem., 1974, 36, 87s. T. B. Brill, J. Magn. Resonance, 1974, 15, 395. F. Boberg and J. Kresse, 2. Naturforsch., 1974, 29b, 213.

Elements of Group V

397

The presence of a square-pyramidal anion has been revealed by an X-ray study of K2SbC15,729 the axial bond being shorter than the mean of the basal bonds, which are distorted as a result of ionic and packing forces. X-Ray p.e. spectra have been reported for M,Sb2X9species, where M = alkali metal and X = C1, Br, or I,',' and this technique demonstrates the presence of both Slow recrystallization of Cs,antimony-(111) and -(v) atoms in CS,S~C~,.'~' Sb,Cl, from dilute hydrochloric acid gives a new @-form in which the caesium and chlorine atoms are in nearly closest packing, with antimony atoms in octahedral The layers are stacked in the order ABACBC, giving rise to two types of SbC1, molecules. Complex tetra-, penta-, and hexa-bromides, together with salts containing the Sb,Br% ion, are the products when SbBr, and amine hydrobromides react in aqueous hydrogen bromide.733 Antimony (v) Compounds. Intercalation of SbF, into graphite occurs very readily, and up to 75% can be incorporated by heating at 110"C for a few D.t.a. studies on solutions of SbF, in water and hydrogen fluoride have defined the thermal treatment required to give crystals of SbF,,2H20, 4SbF,,5Hz0, 3SbF,,2Hz0, and SbFS,HF,2H20.735 Vibrational data for the first and last of these are consistent with the ionic formulations H,O+SbF,OH- and H,O;SbFi, respectively, while donor-acceptor structures are appropriate for the other phases. Both 1: 1 and 1:2 complexes are formed between dimethyl ether and antimony pentafluoride; "F n.m.r. spectra and double-resonance experiments confirm the cis structure (101) for 2SbF,,Me,0.'36 A minor product

from the reaction between SbF, and TeF, has the stoicheiometry TeF4,2SbF, and recently this has been shown to have the formulation 729

730

731

732 '33

734 735

736

R. K. Wismer and R. A. Jacobson, Inorg. Chem., 1974, 13, 1678. M. J. Tricker, Inorg. Chem., 1974, 13, 742. P. Burroughs, A. Hamnett, and A. F. Orchard, J.C.S. Dalton, 1974, 565. K. Kihara and T. Sudo, Actu Cryst., 1974, B30, 1088. N. K. Jha and S. S. A. Rizvi, J . Inorg. Nuclear Chem., 1974, 36, 1479. J. M. Lalancette and J. Lafontaine, J.C.S. Chem. Comm., 1973, 815. B. Bonnet, J. Rozikre, R. Fourcade, and G. Mascherpa, Cunad. J . Chem., 1974, 52, 2077. S. Brownstein and M. J. Farrall, Canad. J . Chem., 1974, 52, 1958.

398

Inorganic Chemistry of the Main - group Elements As is the case in many similar systems, there is considerable cation-anion interaction here through fluorine bridging. Detailed i.r. and Raman data for SbFs,CH,CN are in accord with C,, symmetry for the SbF,N moiety.''' Stabilktion of unusual cations by A s F ~has already been mentioned, and SbFi or SbzF;i are often Convenient alternatives. These have been successfully used in the formation of OlSbF; and 02+sb2~i1,739 C]01Sb2F;1,740 and I:Sb2F1.741 Full structural data are available for the last two compounds. Raman data for SbC1, over a temperature range point to a structure change at -76 "C from the trigonal-bipyramidal monomer to a dimeric form with either D,, or C,,, symmetry.742Two groups of workers report the formation of four hydrates of antimony pentachloride7"'*'"" with from 1 to 4 moles of water. Spectroscopy points to the first being a hydrogen-bonded polymer while the higher hydrates also contain the ionic species [H'(H,0),,][SbC150H]-.743 Enthalpies of complexation with SbCI, for a number of oxygen donors in CCld7",and a series of N-substituted phosph~ramides~'~ have been determined and the 'donor number' has been calculated. A new relationship involving the 'donor number' has been observed from X-ray p.e. spectra of quick-frozen solutions of SbCls.747There is a linear relationship of donor number with the difference in binding energies of the orbitals, implying that on complexation antimony 3&/2 and chlorine 2p1/2,3/2 there is a decrease in the Sb-Cl bond strength and an increase in the d -orbital binding energy. The possibility of a structure involving the acetylium ion appears probable from measurements on the SbC1,-acetic anhydride complex.748 Isomer shifts in the Mossbauer spectra for SbCI5,L, where L = itri rile,'"^ 0PCl3, OPR3, DMF, Cl-,750etc., have been interpreted to show an order of donor power for the ligands. Vibrational assignments and normal-coordinate analyses have been reported for SbCl,,DMSO and SbC15,[2H6]DMS0.7s' Replacement of one chlorine in SbCl, takes place on reaction with sodium ethoxide in dichloromethane, giving the known dimeric ethoxytetrachloride? but definite compounds were not obtained when attempts TembZF~1*737

737

738 739 740 741

742

743 744 745

746

747

748 749

750 751

A. J . Edwards and P. Taylor, J.C.S. Dalton, 1973, 2150. D. M. Byler and D. F. Shriver, Inorg. Chem., 1974, 13, 1412. D. E. McKee and N. Bartlett, Inorg. Chem., 1973, 12, 2738. A. J. Edwards and R. J. C. Sills, J.C.S. Dalton, 1974, 1726. C. G. Davies, R. J. Gillespie, P. R. Ireland, and J. M. Sowa, Canad. J. Chem., 1974, 52, 2048. W. Bues, F. Demiray. and W. Brockner, Spectrochim. Acta, 1974, 30A, 1709. R. Ortwein and A. Schmidt, Z. anorg. Chem., 1974, 408, 42. G. Picotin and P. Vitse, Bull. SOC.chim. France, 1974, 1291. G. Olofsson and I. Olofsson, J. Amer. Chem. SOC.,1973, 95, 731. Y . Ozari and J. Jagur-Grodzinski, J.C.S. Chem. Comm., 1974, 295. K. Burgen and E. Fluck, Inorg. Nuclear Chem. Letters, 1974, 10, 171. K. C . Malhotra and D. S. Katoch, Austral. J. Chem., 1974, 27, 1413. J. M. Friedt, G. K. Shenoy, M. Masson, and M. J. F. Leroy, J.C.S. Dalton, 1974, 1374. J. M. Friedt, G. K. Shenoy, and M. Burgard, J. Chem. Phys., 1973, 59, 4468. M. Burgard and M. J. F. Leroy, J. Mol. Structure, 1974, 20, 153.

Elements of Group V

399

were made to replace further chlorine In the presence of ammonia, however, alcohol reacted complete&, and Sb(OEt),,NH, could be isolated. The monoalkoxy derivatives Sb(OR)Cl, form complexes with a wide variety of amine oxides and phosphine oxides which are monomeric in n i t r ~ b e n z e n e .Monosubstituted ~~~ species also result when antimony pentachloride is treated with either sodium formate or sodium acetate in methylene dichloride,"" and vibrational data for the compounds obtained, SbCl,(O,CH) and SbCI4(0,CMe), have been discussed in terms of monomeric structures. Slightly distorted octahedral SbBr; ions and centrosymmetric Br; ions are present in the structure of (quinolinium),SbBr, according to X-ray diffraction data.755

Bonds to Oxygen.-Mossbauer data have been obtained for (Ph,Sb),O and a series of trialkoxystibines Sb(OR),, where R = E t , Pr, Bun, or Cyclic esters, analogous to those discussed above for arsenic, can be obtained with antimony as the central atom by reactions between PhSbC1, and diols, dithiols, or m0n0thiogly~o1~.~~~ In the refinement of the crystal structure of orthorhombic antimony(rr1) oxide, it was shown that each antimony is co-ordinated to three oxygen atoms (mean Sb-0 2.01 A), with the lone pair completing a pseudo-tetrahedral arrangement.758By sharing corners, these tetrahedra form double infinite chains with the lone pairs pointing outwards. Raman and i.r. data for the oxide halides Sb405C12and Sb405Br2have been obtained and discussed in terms of lattice vibrations.759The analogous iodide is not, however, among the phases identified in an analysis of the Sb,O,-SbI, system, only Sb,O,I, Sb,O,,I, and Sb,071 being detected.760The exact modification of antimony(r1r) oxide obtained by thermal decomposition of Sb,OllCl, depends on the method used for preparing the latter.761With material obtained by decomposing Sb,O,Cl at 460 "C, the product is the less common cubic form of Sb203. The antimony(m) hydroxy-species existing in nitric acid solution was previously thought to be Sb,O,(NO,),H,O, but according to an X-ray Both determination the material is best described as Sb404(OH)2(N0,)2.762 trigonal-bipyramidal SbO, and tetrahedral SbO, units are present R.-A. Laber and A. Schmidt, Z . anorg. Chem., 1974, 405, 71. R. C. Paul, H. Madan, and S. L. Chadha, J. Inorg. Nuclear Chem., 1974, 36, 737. 754 R.-A. Laber and A . Schmidt, Z . anorg. Chem., 1974, 407, 237. 7 5 5 S. L. Lawton, E. R. McAfee, J. E. Benson, and R. A. Jacobson, Inorg. Chem., 1973, 12, 2939. 756 L. H. Bowen, G. G. Long, J. G. Stevens, N. C. Campbell, and T. B. Brill, Inorg. Chem., 1974, 13, 1787. 757 M. Wieber and N. Baumann, 2. anorg. Chem., 1973, 402, 43. C. Svensson, Acta Cryst., 1974, 1130, 458. 759 K. I. Petrov, Yu. M. Golovin, and V. V. Fomichev, Russ. J. Inorg. Chem., 1973,18, 1554. 760 A. M. Klimakov, B. A. Popovkin, and A . V. Novoselova, Doklady Chem., 1973,213,858. 761 R. Matsuzaki, A. Sofue, and Y. Saeki, Chem. Letters, 1973, 1311. 762 J . - 0 . Bovin, Acta Chem. Scand. ( A ) , 1974, 28, 267. 752

753

400

Inorganic Chemistry of the Main-group Elements (in each case the lone pair occupies the final co-ordination position). The former share two edges to build up infinite chains parallel to b, which are linked by the SbO, polyhedra into layers parallel to the bc plane. Two new phases, Sb,MoO, and Sb,(MoO,),, have been identified in the Sb,O,-MoO, and the rare-earth antimonites LnSbO, result when mixtures of the two oxides are sintered at 650°C.764A second report announces similar compounds but the formula is given as 2Ln,03,x Sb203, where x = 3.0-3.8 for Ln =La, Pr, or Nd.765Unit-cell parameters are available for NazSb407and NaSb30,,Hz0,766 and powder neutron-diffraction results have been obtained for the ordered perovskite-like compounds Ba,Sb,LiO,, and the bismuth analogue.767 From solubility measurements on NaSb(OH),, the enthalpy of hydration Addition of has been estimated as -124 kJ mol-' for the [Sb(OH),]acid to a solution of tetraethylammonium antimonite does not immediately lead to the [Sb(OH),]- ion; initially a polymer of high molecular weight is formed, which on long ageing breaks down via various polymeric substances to the monomer.769 Vibrations characteristic of Sb-0 stretches and deformations have been discussed for solid antimonates such as M'SbO,, M"SbzOs, and MYSb207."" Preparation of a new family of mixed oxides with structures related to that of cubic KSbO, has been announced, and the detailed structure of one such compound, Bi,GaSb,O,,, has been Potassium ion transport can occur through two-dimensional tunnels that occur in the structures of K,Sb,O,, and K2Sb4011.772

Bonds to Sulphur, Selenium, or Tellurium.-Electrical and thermal conductivities have been reported for the chalcogenides M'SbS2 and M'SbSe2,773 and X-ray data for aramyoite, Ag(Sb,Bi)S2."" The presence of a Bi,Se,S structure in Sb,Te, and Sb,Te,Se follows from X-ray data, and the relationship with the non-stoicheiometric Sb2Te3-,Se, compounds has been disMass-spectrometric measurements on the vapour in equilibrium with Sb2Te, lead to values of 65.4 and 179.9 kcal mol-' for the heats of atomization for SbTe and Sb2Te2,respectively.776 M. Parmentier, A. Courtois, and Ch. Gleitzer, Bull. Soc. chim. France, 1974, 75. S. N. Nasonova, V. V. Serebrennikov, and G. A. Narnov, Russ. J. Inorg. Chem., 1973, 18, 1095. 765 G.-Y. Adachi, M. Ishihara. and J. Shiokawa, J. Less-Common Metals, 1973, 32, 175. 766 C. Giroux-Maraine, P . Maraine, and R. Bouaziz, Cornpt. rend., 1974, 278, C, 705. 767 A. J. Jacobson, B. M. Collins, and B. E. F. Fender, Acta Cryst., 1974, B30, 1705. 7h8 M. J. Blandamer, J. Burgess, and R. D. Peacock, J.C.S. Dalton, 1974, 1084. 76y J. Lemerle and J. Lefehvre, J. Chim. phys., 1974, 71, 97. "'R. Franck, C. Rocchiccioli-Deltcheff, and J. Guillermet. Spectrochim. Acta, 1974, 30A, 1 ; C . Rocchiccioli-Deltcheff and R. Frank, Ann. Chim. (France), 1974, 9, 43. A. W. Sleight and R. J. Bouchard, Inorg. Chem., 1973, 12, 2314. 772 H. Y.-P. Hong, Acta Cryst., 1974, B30, 945. 773 V. A. Razakutsa, N. I. Gnidash, V. B. Lazarev, E. 1. Rogacheva, A. V. Salov, L. N. Sukhorukova, M. P. Vasil'eva, and S. I. Berul', Russ. J . Inorg. Chem., 1973, 18, 1722. 7 7 4 D. J. E. Mullen and W. Nowacki, Z . Krist., 1974, 139, 54. 7 7 5 T. L. Anderson and B. Krause, Acta Cryst., 1974, B30, 1307. 77h C. L. Sullivan, M. J. Zehe, and K. D. Carlson, High Temp. Sci., 1974, 6 , 80. 76' 764

Elements of Group V

40 1

5 Bismuth

Structures for two bismuthides, BazBi”’“ and CasBi,,777bshow the presence of bismuth in nine-fold co-ordination in the former, while two different co-ordination polyhedra, showing eight- and nine-fold co-ordination, occur in the latter. Powder neutron-diffraction data for BiF, show eight-fold co-ordination for bismuth (Bi-F 2.217-2.502&, but from a comparison with the isostructural YF, it is clear that the lone pair is stereochemically active and occupies a ninth co-ordination New vapour-pressure measurements are now available for BiCl, over the temperature range 151437 0c.779 Competition between Cl-, Br-, and NO; for entry into the co-ordination spheres of Bi3+and Pb2+has been investigated in molten dimethyl sulphone to show the order C1- > Br- >> NO;.780These data are relevant to basicity measurements in molten salts and glasses.781The BiC1,-LiCl system shows the presence of LiCl, BiCl,, and LiC1,4BiC13 A new compound of mixed oxidation state is the product from reduction of a mixture of BiCl, and HfCl, with metallic Full identification was achieved only by an X-ray structure determination, which showed the composition to be Bi+Bi<+(HfCg-),.140 The hafnium anions are distorted octahedral while the Bi:+ ion has C,, symmetry. Co-ordination of the Bi+ ion is unusual as it is co-ordinated to three chlorines from the anions. Bismuth sulphate, BiZ(SO4),,begins to decompose at 465 “C, giving Biz03,2Bi2(S04),,while at 920 “C the final product is Bi20,.784Identification of the species 2Biz03,Bi,(S04),, 7Biz0,,2Biz(S04)3, 12BiZO3,Biz(SO4),,and 28Biz0,,Biz(S04),was possible at intermediate temperatures. Oxidation of the bismuth tellurites Bi,-,Te,0~3+x),2 has been found to be reversible and gives the new compounds BisTezO,, and BizTe06.785The PbO-Bi,O, system has been investigated? showing the formation of five compounds,786and a number of rare-earth bismuthates have been prepared and ~haracterized.”~ On heating a mixture of Biz03+2Ru02 in air the product is an oxygen-rich compound with a formula close to B~,Ru,O,,.~~~ This is perhaps Bi,Ru,O,,, with a structure similar to that of the recently described compound Bi,(GaSbz)Ol,. Alkali-metal bismuth molybdates and tungstates 77’

778 779 780

781 782

783 784

785

787

788

(a) M. Martinez-Ripoll, A . Haase, and G. Brauer, Acta Cryst., 1974, B30, 2003; ( b ) ibid., p. 2004. A. K. Cheetham and N. Norman, Acta Chem. Scand. (A), 1974, 28, 55. M. Yanai, F. Watanabe, and Y . Saeki, J. Less-Common Metals, 1973, 33, 387. J. A . Duffy and M. D. Ingram, J. Inorg. Nuclear Chem., 1974, 36, 39. J. A . DuEy and M. D. Ingram, J . Inorg. Nuclear Chem., 1974, 36, 43. N. I. Kaloev and A . K. Tebiev, Russ. J . Inorg. Chem., 1973, 18, 714. R. M. Friedman and J. D. Corbett, Inorg. Chem., 1974, 13, 1134. R. Matsuzaki, A. Sofue, H. Masumizu, and Y. Saeki, Chem. Letters, 1974, 737. B. Frit and M. Jaymes, Bull. SOC. chirn. France, 1974, 402. J.-C. Boivin and G. Tridot, Compt. rend., 1974, 278, C, 865. S. N. Nasonova and V. V. Serebrennikov, Russ. J. Inorg. Chem., 1973, 18, 897; S. N . Nasonova, V. V. Serebrennikov, and G. A . Narnov, ibid., p . 1244. F. Abraham, G. Nowogrocki, and D. Thomas, Compt. rend., 1974, 278, C, 42.

402

Inorganic Chemistry of the Main-group Elements

can be recrystallized from molten di-molybdate and -tungstate and a low-temperature method for preparing the catalytically useful bismuth uranates has been devised.79" Interest in the stereochemical consequences of the lone pair in Bi"' continues with the determination of the structure of the di-isopropylphosphorodithioate (102).791The six sulphur atoms are co-ordinated, giving

overall CJusymmetry, with the lone pair occupying a position in one of the faces of the distorted octahedron. The Bi-S bonds adjacent to this lone pair are longer (mean length 2.874A) than the remote three (mean length 2.702 A). Bismuth atoms at the centres of three different co-ordination polyhedra have been observed in the structure of C U B ~ , S , while , ~ ~ ~ in RbBi,S, all the bismuth atoms are octahedrally co-~rdinated.'~~ The reaction between Bi,S,, PbS, and CuS in the presence of hydrogen chloride gives Bi2Cu,S4Cl,which contains linked chains of the type (Bi2S4)2-and (BiS2Cl)z-.794 The structure of BiSI is built up of (Bi2Sz12),double chains parallel to the c -axis.7y5The compound BiI9S2,Br3,obtained by high-temperature methods, and the analogous iodide are isostructural, but attempts to prepare the chloride were unsucces~fu1.~~~ A new metastable modification of bismuth selenide, Bi2Se3-11, has been characterized and has a structure closely related to that of Sb2S3.797 789 79n 791

792

7y3 794

795 796

797

P. V. Klevtsov, V. A . Vinokurov, and R. F. Klevtsova, Soviet Phys. Cryst., 1974, 18, 749. C. V. Gurumurthy, Indian J. Chem., 1974, 12, 212. S. L. Lawton, C. J. Fuhrmeister, R. G. Haas, C. S. Jarman, jun., and F. G. Lohmeyer, Inorg. Chem., 1974, 13, 135. M. Ohmasa and W. Nowacki, Z. Krist., 1973, 137, 422. D.Schmitz and W. Bronger, 2. Naturforsch., 1974, 29b, 438. J. Lewis, jun., and V. Kufkik, Actu Cryst., 1974, B30, 848. W. Haase-Wessel, Nuturwiss., 1973, 60, 474. V. Kramer, J. Appl. Cryst., 1973, 6, 499. E. Ya. Atabaeva, S. A. Mashkov, and S. V. Popova, Soviet Phys. Cryst., 1973, 18, 104.

6 Elements of Group VI BY M.

G. BARKER

1 Oxygen The Element.-Three reviews concerned with the properties and uses of molecular oxygen have been published this year. The first' deals with the applications of oxygen isotopes to research and technology. Areas covered include isotope and fractionation effects, isotopic labelling, n.m.r. qnd e.s.r., and nuclear reactions. Catalytic oxidation by molecular oxygen is the subject of the second review.' Autoxidation and photo-oxidation reactions, heterogeneous catalytic oxidation in the gas phase, and catalytic oxidation in the liquid phase are discussed. The third review is concerned with molecular oxygen as a ligand in transition-metal complexe~.~ Several complexes and the kinetics and mechanism of their formation are presented. The influence of other ligands on the activation of oxygen is discussed on the basis of an MO description of the electronic structure of the oxygen molecule and of the bonding within the metal-oxygen complexes. Reactions of co-ordinated oxygen are also described. An automatic apparatus for monitoring the evolution or absorption of oxygen has been d e ~ c r i b e dThe . ~ chemiluminescence method of detecting small quantities of 0, was used, the sensitivity of the apparatus being s-l. The 304 A photoelectron spectra of 02,Nz, CO, and C 0 2 1012(mole02) have been measured.' For all the molecules, transitions to electronic states with ionization potentials in the range 30-40.8 eV were shown to be dissociative. The high-resolution vibrational Raman spectrum of oxygen has been recorded.6 Calculated molecular parameters agreed well with those previously reported from microwave and electronic spectra. The state of adsorbed oxygen on metallic silver dispersed on silica gel has been studied by e . ~ . rBoth . ~ 0;and Ag2' were observed on the surface. The i.r. spectrum of a gaseous mixture of oxygen and argon at 9 3 K reveals discrete features

' D. Staschewski, Angew. Chem. Internat. Edn., 1974, 13, 357. J. Scheve and E. Scheve, 2. Chem., 1974, 14, 172. G. Henrici and S. OlivC, Angew. Chem. Internat. Edn., 1974, 13, 29. V. A. Ilatovskii, Yu. S. Shumov, and G. G . Komissarov, Russ. J. Phys. Chern., 1973, 47, 669. J. L. Gardner and J. A. R. Samson, J. Electron Spectroscopy, 1973, 2, 259. ' W. H. Fletcher and J. S. Rayside, J. Raman Spectroscopy, 1974, 2, 3. ' N. Shimizu, K. Shimokoshi, and I. Yasumori, Bull. Chem. SOC.Japan, 1973, 46, 2929.

403

404

Inorganic Chemistry of the Main-group Elements

which have been attributed' to absorption by the 02-Ar van der Waals molecule. The spectrum occurs near the i.r.-inactive vibration of 0,. One band corresponds to the stretching frequency of 0, within the molecule; an analysis of the P and R envelope of this band gave an approximate intermolecular distance of 3.5 A. Calculations, within the CNDO framework, have been performed' on a wide range of molecules containing oxygen. By use of the density-matrix elements, the valencies of all the atoms were calculated. In neutral species an oxygen atom is approximately bivalent in character. In anions of the type XOk-, however, the valency drops to a value between 1.3 and 1.7 or lower when d-orbitals are included o n the central atom. It was thought that the excess of unused bonding power of oxygen is used to interact covalently with cations, as in the formation of sulphato-complexes and in sequestering agents. The existence of oxygen in different oxidation states in the phosphocalcium and phosphostrontium apatite lattice has been observed." In these apatites, channels are filled with oxygen in the oxidation states OH-, OX-, and 0,. The paramagnetism of apatites originates from molecular oxygen and also from the presence, at low concentrations, of O;, which has been observed by e.s.r. The reduction of oxygen on a carbon paste electrode in an alkaline medium has been investigated'' by voltammetry. Measurements of the rate of isotope exchange between gaseous oxygen and molten sodium hydroxide show a first-order reaction with respect to oxygen.'' The higher rate of exchange and lower activation energy than in systems comprising oxygen with metal oxides and with alkali-metal oxysalts are explained by the presence of a hydrogen bond of the type 0 - - H-0. The reaction of oxygen atoms with diborane has been studied13 in a discharge-flow reactor using a time-of-flight mass spectrometer as a detector. The species H,O, BH20t, and possibly BH,O were observed as products or intermediates, and the presence of O H was inferred. With B,H, in excess, a chain reaction initiated by:

-

0 +B,H,

--j

BH,O +BH,

(1)

and propagated by: BH,+O-+OH+BH, OH + B,H, + H,O + BH, + BH,

(2) (3)

is thought to take place. When oxygen atoms are in excess, B,Hs disappearance is controlled by reaction (l), while oxygen atoms are catalytically G. Henderson and G. E. Ewing, J. Chem. Phys., 1973, 59, 2280. D. R. Armstrong, P. G. Perkins, and J. P. Stewart, J. C. S. Dalton, 1973, 2273. lo J. C. Trombe, A n n . Chim. (France), 1973, 8, 335. M. Brezina-and A. Hofmanova-Matejkova, Coll. Czech. Chem. Comm., 1973, 38, 3024. l 2 Yu. M. Baikov, Russ. J. Phys. Chem., 1973, 47, 720. l 3 C. W. Hand and L. K. Derr, Inorg. Chem., 1974, 13, 339.

Elements of Group VI

405

removed in the sequence: O+B,H,+BH,+BH,O BH,O + 0 3 BH, + O2

(4)

2BH, + B,H,

(6)

(5)

A kinetic study of the oxidation of sulphite ions to sulphate ions by gaseous oxygen in melts of lithium and potassium chlorides at temperatures between 414 and 504°C has been carried out, and a possible reaction mechanism proposed.14 The interaction of oxygen at 20 "C with hydrogen sulphide presorbed at 55°C and vice versa has been in~estigated.'~ Ozone. The high-resolution photoelectron spectroscopy of ozone has been the subject of two recent publications. The first16was performed using both He I and Ne I (16.7 eV) radiation on a pure ozone sample. The second" used He I and He I1 radiation, on a slightly less pure sample, since the spectrum showed a signal from oxygen at a few percent intensity. The results of both investigations are shown in Table 1, and it may be seen that they differ not only in the proposed orbital ordering, but also in the positive identification of an extra band in the spectrum between 16.5 and 18.5 eV. Table 1 Ionization potentials of ozone. Frost et a1.16 I.P.IeV Orbital

1st 2nd 3rd

12.53 6a, 12.75 13.03 la, 13.57 4b2

4th,5th

20.3

-

-

-

lb1,3b2

Brundle l 7 LP./eV

1st 2nd

3rd 4th,5th,6th 7th

12.56 12.75 13.02 13.57 16.5-18.5 18.7-21.5

Orbital 6a1 4b2,lUz lbl,3b,,5al 4al

Several papers have been published on the chemistry of ozone in relation to studies of the atmosphere. Subjects covered include; the discrepancy between observed and theoretical concentrations of ozone in the mesosphere," energy processes involving O2 and 0 3 , 1 9 excited-state chemistry of 0,and 0 3 , ' 0 ozone distribution in the atmosphere,21and photochemistry in the upper atmosphere.2' The contradictory published data on the electrosynthesis of ozone from air have been discussed.23 Experimental kinetic P. Pacak, J. Novak, and I. Slama, Coll. Czech. Chem. Comm., 1973, 38, 3589. A. Rudajevova and V. Pour, Coll. Czech. Chem. Comm., 1974, 39, 2130. l6 D. C. Frost, S. T . Lee, and C. A. McDowell, Chem. Phys. Letters, 1974, 24, 149. l7 C. R. Brundle, Chem. Phys. Letters, 1974, 26, 25. l 8 M. Nicolet, Canad. J. Chem., 1974, 52, 1381. l9 R. L. Taylor, Canad. J. Chem., 1974, 52, 1436. 'O R. J. Cvetanovic, Canad. J. Chem., 1974, 52, 1452. '* H. U. Dutsch, Canad. J. Chem., 1974, 52, 1491. 22 P. Crutzen, Canad. J. Chem., 1974, 52, 1569. 23 0. M. Knipovich, Yu. M. Emel'yanov, and Yu. V. Filippov, Russ. J. Phys. Chem., 1973, 47, 1472. l4

l5

406 Inorganic Chemistry of the Main-group Elements curves obtained at constant air-flow rate and constant discharge power show a maximum, the concentration of ozone falling to zero as the specific energy increases. The role of the oxides of nitrogen, formed in the discharge, has been studied by the same authors? and by two independent groups25’26 The reaction of ozone with chlorine, where reaction is induced by light of wavelength 365-366.5 nm, has been s t ~ d i e d . ’The ~ only chlorine oxide observed was dichlorine heptoxide, in contradiction of previous studies. It was proposed that Cl,O, is formed by a step-wise, non-chain series of reactions involving ozone and a number of intermediate chlorine oxides. The key to the mechanism is the formation of a chlorine atom-ozone complex, c103, which can be stabilized by a third body, allowing further step-wise formation of Cl,07. It has been shownZs that ozone reacts with Cu(OH), at pH 7-9 and 50°C to give crystalline CuO, but does not react with CuX, (X = CI- or NO;; X, = SO:- or COZ-) in acid or neutral solutions.

Oxygen Fluorides.-An open-shell CNDO treatment has been employedz9 in order to interpret the electronic spectra, ionization potentials, and electron affinities of radicals containing 2, 3, and 4 atoms, including FOz and HO,. Raman spectra of O,F, in CClF, have been measured for the first time .30 Hydrogen Peroxide.-Thermochemical measurements of the heat of reaction of hydrogen peroxide with MnO,, Ce4+,I-, Fez+,and Mo”’ in H2S0, medium have been carried The He I photoelectron spectrum of hydrogen peroxide shows a splitting of 1.0 eV between the first two bands, due to the oxygen non-bonding orbital~.~’ CND0/2 calculations indicate that the non-bonding orbital splitting, as well as the orbital assignment, depend largely upon the dihedral angle between the two halves of the molecule. A systematic investigation has been carried of the vibrational spectra of the hydrogen peroxide crystal and its deuteriated analogue, using both i.r. and Raman spectroscopy, over the range 4000-50cm-’. Mixtures of the two isotopic species up to approximately 95% deuteriation were also studied to identify the fundamentals of the hybrid molecule HDO,. Nearly all the 0-H stretching components predicted by the factorgroup analysis were observed, but a satisfactory identification of all components of the OOH deformation modes could not be achieved. The 0-0 24

0. M. Knipovich, Yu. M. Emel’yanov, and Yu. V. Filippov, Russ. J. Phys. Chem., 1973, 47,

1474. C. H. Wu, E. D. Morris, and H. Niki, J . Phys. Chem., 1973, 77,2507. 26 D. D. Davis, J. Prusazcyk, M. Dwyer, and P. Kim, J . Phys. Chem., 1974, 78, 1775. ’’ R. W. Davidson and D. G. Williams, J . Phys. Chem., 1973, 77,2515. 2R A. F. Chudnov, Zhur. obshchei Khim., 1974, 44, 1207. 2Q P. Carsky, M. Machacek, and R. Zahradnik, Coll. Czech. Chem. Comm., 1973, 38, 3067. 30 J. K. Burdett, D. J. Gardiner, J. J . Turner, R. D. Spratley, and P. Tchir, J. C. S . Dalton, 1973, 1928. 3 1 J. Brandstetr and P. Sapakova, Coll. Czech. Chem. Comm., 1973, 38, 2249. 3 2 K. Osafune and K. Kimura, Chem. Phys. Letters, 1974, 25, 47. 33 J . L. Arnau, P. A. Giguere, M. Abe, and R. C. Taylor, Spectrochim. Actu. 1974, 30A, 777. 25

Elements of Group VI 407 stretching frequency in D z 0 2 (872~11-l)is slightly higher than in H20, (871 cm-I), contrary to expectations. The hydrogen bonds in the HzOz crystal appear somewhat less strong than those in ice. The pyrolysis of H20, has been followed mass spectrometrically under conditions such that a steady-state concentration of the HO, radical, equal to or exceeding times the concentration of the Hz02,would have been detected.34The actual concentration of the HO, in the reacting mixture was found to be below the detection limit; from which it was concluded that the simplest mechanism that provides an entirely quantitative description of the pyrolysis is : H,02+M+20H+M

(7)

OH+H,O,+HO,+H,O

(8)

2HO2 + HzOz + 0,

(9)

The decomposition of hydrogen peroxide on the surface of cobalt sulphide has been studied.” An investigation of the kinetics of the catalytic decomposition of hydrogen peroxide in the presence of the hydroxides of the Group I11 p, d, and f elements, and of the synthesis and properties of the peroxide products, has been carried The principal conclusions drawn from a combination of experimental and literature data were: (i) the formation of a series of peroxide products, the stability of which is inversely proportional to the peroxide oxygen content, and which decompose consecutively, is a property of all the elements. (ii) In most cases the kinetic curves for the decomposition of the peroxides, in the solid state and in distilled water, have similar shapes. (iii) The hydroperoxide structure for the d and f elements was not confirmed. (iv) The peroxides of indium and gallium may, however, have the structure of peroxyhydrates. (v) Many properties of the peroxides, and hence their structures, are functions of the conditions of their preparation and subsequent storage. Other Hydrogen-Oxygen Compounds. Ab initio (LCAO-MO) calculations of experimental force constants, bond lengths, and energies have been to discuss the nature of the inter-oxygen bonding in 0,, HO,, K O 2 , 03, HO,, and H,. The species HO, is estimated to be approximately 15 kcal mo1-I unstable with respect to O,+OH, thus making unlikely its potential role as a reaction intermediate. HzO, is calculated to have 0-0 bonds slightly shorter (- 1.44 A) than in H,O, (1.48 A), but with 0-0 force constants simil