Inorganic chemistry

INORGANIC CHEMISTRY. THEORETICAL advances of considerable importance in the interpretation of the structures of many types of inorganic compound have been reported during the year ; these mainly concern the participation of d-orbitals in covalent bonding, and the nature of the bonding in the higher hydrides of boron and in the cyczopentadienyls of the transition metals. The recognition over twenty years ago that d orbitals can combine with s and 9 orbitals to form hybridised groups of equivalent orbitals with strongly directional properties resulted in great advances in the understand- ing of inorganic stereochemistry. This success directed attention mainly to the angular properties of atomic orbitals, but recently it has been realised that d orbitals are likely to participate in bonding in other ways, for example by the formation of d,-p, bonds which would account for the double bonding apparent in groups like sulphate,l and by the formation of dn-dT bonds to account for the striking difference between co-ordination by oxygen and nitrogen on the one hand and heavier donors such as sulphur, phosphorus, and arsenic on the other.2 Quantitative investigations of these effects have directed attention more particularly to the radial parts of atomic orbitals. Thus it has been shown that the 3d orbitals of neutral atoms of phosphorus and sulphur are too diffuse to combine effectively with the more compact 3s and 3p orbitals, L e . , the radial parts of the d-orbitals diminish with dis- tance from the nucleus much more slowly than those of the s or p orbitals. This prevents effective overlap and the formation, for example, of satis- factory sp3d2 octahedral orbitals, though highly stable octahedral compounds of these elements are known (e.g., sulphur hexafluoride and the PF,- ion). The difficulty has been largely resolved by considering the relative polaris- abilities of the orbitals concerned. The d orbitals are more polarisable than s and 1) orbitals, and those of phosphorus and sulphur would contract more than s or p orbitals if the phosphorus or sulphur acquired a positive charge due to bonding to more electronegative atoms. This explains why these elements exert their highest covalencies only when bound to the most electronegative atoms, notably fluorine. This is true generally of elements in which d orbitals available for bonding are of the same principle quantum group as the s and p orbitals. Conversely, d orbitals available for bonding, which belong to a lower principal quantum group than the s and p orbitals also involved in bonding, are generally too compact for effective overlap. This occurs with the transition metals, and in such instances hybridisation involving d orbitals together with s and p orbitals is favoured by bonding to the less electro- negative elements. For example, it has been noted that nickel tends to form tetrahedral ( s $ ~ ) complexes with the more electronegative ligands and planar (as@*) complexes with less electronegative ligands ; likewise copper (11) which normally forms sp2d bonds with the electronegative atoms oxygen and nitrogen uses the 4d and not the 3d orbital. 1 G. M. Phillips, J. S. Hunter, and L. E. Sutton, I., 1945, 146. 2 U. K. Syrkin, Izvest. Akad. Nauk S.S.S.R., Otdel. Khinz. Nauk, 1948, 75; J . Chatt, Nature, 1950, 165, 637. Pu bl is he d on 0 1 Ja nu ar y 19 54 . D ow nl oa de d by U ni ve rs ity o f C al if or ni a - R iv er si de o n 29 /1 0/ 20 14 1 7: 30 :3 3. View Article Online / Journal Homepage / Table of Contents for this issue http://dx.doi.org/10.1039/ar9545100118 http://pubs.rsc.org/en/journals/journal/AR http://pubs.rsc.org/en/journals/journal/AR?issueid=AR1954_51_0 COATES AND GLOCKLING. 119 The overlap of d orbitals with 9, or d, orbitals, giving double bonds, has been found to be satisfactory in most cases in which i t has been supposed to occur, and appears to be rather less sensitive to changes in the radial parts of the atomic orbitals. It is mainly in connection with the formation of G bonds by hybridised orbitals involving d atomic orbitals that the very important influence of electronegativity has to be considered., Several discussions have appeared concerning the bonding in the higher boron hydrides,* most of the structures now having been determined experi- mentally, including that of the unstable pentaborane, B,H11,5 and there are preliminary results for hexaborane, B6H10.6 The nature of the bonding in the biscyciopentadienyl derivatives of the transition metals now seems to be fairly well understood, and the magnetic properties of the compounds have been e ~ p l a i n e d . ~ The extent to which 6 bonding, which bears the same relation to x bonding as x to G, takes part is not yet quite clear,,, and the structures of the interesting carbonyl- cyclopentadienyls of vanadium, molybdenum, and tungsten are not yet understood. The existence of two more hydrides of boron, octaborane and nonaborane, has been confirmed, and some hydrides and methylated nitrides of beryllium are reported. Subhalides have received considerable attention, particularly that of boron, B,Cl,, which reacts in an interesting way with ethylene, but the sub- halides of calcium, silicon, germanium, niobium, and tantalum have also been studied. The chemistry of nitrogen has been extended by the addition of numerous azides, e g . , BN,, SiN,,, and Na,SnN,,. Many of these are sensitive to shock. There have been more advances in the chemistry of sulphur, and of sulphimide (HN-SO,), in particular, and a new oxynitride, S,N205, has been described. The cyclopentadienyl group of compounds has been intensively studied and now includes several carbonyl-cyclopentadienyls, e.g., C,H,V(CO),, and some indenyls of which the yellow liquid bistetrahydroindenyliron, (CsH,1)2Fe is an example. Some of the most interesting advances during the year have again concerned carbonyls and mixed carbonyl-cyanides, particularly those of cobalt, e g . , the addition of dicobalt octacarbonyl to acetylenes. The series of isocyanide complexes of the transition metals has been extended and now includes such compounds as [Co(CNR),](ClO,), and W(CNR),. Review articles have been published on co-ordination compounds,8 the significance of magnetic measurements in inorganic chemi~t ry ,~ boron tri- fluoride co-ordination compounds, lo the reactions of inorganic iodine com- 3 D. P. Craig, A. Maccoll, R. S. Nyholm, L. E. Orgel, and L. E. Sutton, J., 1064, 332. 4 W. N. Lipscomb, J . Chem. Phys., 1054, 22, 985; W. H. Eberhardt, 13. Crawford, L. R. Lavine and W. N. Lipscomb, ibid. , p. 614. 6 K. Eriks, W. N. Lipscomb, and R. Schaeffer, ibid. , p. 764. 7 W. Moffitt, J . Anzer. Chem. SOC., 1954, 76, 3386; F. Cotton and G. Wilkinson, Z. Naturforsch., 1954, 9b, 453. 8 W. Wark, D. P. Craig, R. S. Nyholm, L. N. Short, D. P. Mellor, D. D. Brown, N. 13. Dsvies, E. C. Gyarfas, G. A. Barclay, B. J. Ralph, W, A. Rawlinson, and N. A. Gibons, Rev. Pure Apjd . Clzenz. (Australia), 1954, 4, 110. s R. S . Nyholm, Quart. Rev., 1953, '7, 377. 10 N. N. Greenwood and R. L. Martin, ibid., 1954, 8, 1. and W. N. Lipscomb, ibid. , p. 989; J . R. Platt, ibid., p. 1033. Pu bl is he d on 0 1 Ja nu ar y 19 54 . D ow nl oa de d by U ni ve rs ity o f C al if or ni a - R iv er si de o n 29 /1 0/ 20 14 1 7: 30 :3 3. View Article Online http://dx.doi.org/10.1039/ar9545100118 120 INORGANIC CHEMISTRY. pounds,ll isotopic exchange reactions in aqueous solution,12 the alkali- metal amides, 13 the polymeric inorganic phosphates, l4 zirconium,l5 and elements 85 and 87.16 Complexes.-Since so many complexes, whose formation constants are of interest, are only sparingly soluble in water, quantitative measurements have frequently been made in alcohols or in mixtures of water with organic solvents (often dioxan). Activity coefficients commonly depart very far from unity in such solvents and the effect of this on the calculation of form- ation constants has continued to receive attention. The difficulty can partly be overcome by the introduction of correction terms1' An ingenious procedure has been devised whereby proton-ligand formation constants (related to ordinary acid-base dissociation constants), which are required in the calculation of metal-ligand formation constants from experimental (generally pH) data, are not calculated from thermodynamic and accurate dissociation constants but are obtained by a set of experiments closely similar to those required to provide the metal-ligand stability data. In this way errors due to lack of knowledge of activity coefficients can be made to cancel, and accurate stoicheiometric formation constants can be obtained.ls The method has been applied to the determination of the formation constants of a number of metal chelates with several derivatives of 8-hydroxyquin- oline. l 9 However, experiments on the stabilities of S-hydroxyquinoline- 5-sulphonic acid complexes of eleven bivalent metals, the complexes being soluble in water, suggest that the sulphonic acid group has little influence on the stability of the Formation constants for a variety of complexes have been determined potentiometrically in 75% dioxan-25% water.21 Polarographic methods have also been applied to the measure- ment of formation constants, e.g., of complexes with ethylenediaminetetra- acetic acid (heat and entropy data have also been obtained 22), cyclohexane- 1 : 2-diaminetetra-acetic acid,23 and 1 : 3-diaminopropane.24 The view that the stability of metal chelate complexes decreases with increasing ring size has been strengthened by a careful study of the complexes formed by copper, nickel, and cadmium with some diamines, amino-acids, and dibasic acids .2g The decreased stability constants for N N - and NN'-dialkylethylene- diamine complexes with nickel, copper, and zinc ions (relative to ethylene- diamine complexes) illustrate the effect of steric hindrance on co-ordination, which also accounts for the preferential formation of basic or polynuclear complexes when highly substituted ligands are Substitution of Steric aspects of complex formation continue to be studied. l1 K. J. Morgan, Quart. Rev., 1954, 8, 123. l 3 R. Levine and W. C. Fernelius, Chem. Rev., 1954, 54, 449. l4 C. F. Callis, J. R. Van Wazer, and P. G. Arvan, ibid., p. 777. l5 W. B. Blumenthal, I n d . Eng. Chem., 1954, 46, 528. l6 E. K. Hyde, -1. Phys. Chem., 1954, 58, 21. l7 L. G. Van Uitert and W. C. Fernelius, J . Amer . Cheuvt. SOC., 1954, 76, 5887. H. M. Irving and H. S. Rossotti, J., 1954, 2904. l9 Idem, ibid., p. 2910. 2o R. Nasanen and E. Uusitalo, A d a Chem. Scand., 1954, 8, 112. 21 L. G. Van Uitcrt and W. C. Fernelius, J . Amer. Chem. SOC., 1954, 78, 375. 23 R. G. Charles, ibid., p. 5854. 23 G. Schwarzenbach, R. Gut, and G. Anderegg, Helu. Chim. Acta, 1954, 37, 937. 24 H. M. Irving, R. J. P. Williams, D. J. Ferrett, and A. E. Williams, J. , 1954, 3494. 2 5 H.M. Irving and J. M. iM. Griffiths, ibid., p. 213. l2 C. B. Rmphlett, ibid., p. 519. Pu bl is he d on 0 1 Ja nu ar y 19 54 . D ow nl oa de d by U ni ve rs ity o f C al if or ni a - R iv er si de o n 29 /1 0/ 20 14 1 7: 30 :3 3. View Article Online http://dx.doi.org/10.1039/ar9545100118 COATES AND GLOCKLING. 121 isopropyl groups (e.g., NHPri CH,*CH,*NHPri) even prevents the formation of the ordinary type of complex with nickel and copper.26 Similar effects have been observed with N-is~propylglycine.~' Substitution of the C-H groups in ethylenediamine has a much smaller effect, as might be expected. However, it is interesting to note that (&)-butylene- and (*)-stilbene- diamines are less strongly chelating than the corresponding meso-compounds, and that C-tetramethylethylenediamine forms a yellow diamagnetic complex with nickel(=) of the type [Ni diamine2]X2.28 An empirical relation has been found between electronegativitiy values as calculated by M. Haissinsky 29 and the stabilities of metal complexes ; 30 this is essentially in agreement with the Irving-Williams order mentioned in last year's Reports.31 o-Aminobenzaldehyde forms a number of tris-anhydro-complexes some- what analogous to the formation of phthalocyanines from I phthal~nitri le.~~ Kojic acid (I) forms chelated complexes with a variety of metal ions. These complexes are very HO.CH,I IFo stable, being comparable with those of tropolone and the p-diketones.= Aquation rate constants have been determined for the replacement of thiocyanate by water in the complexes Cr(NH,) ,SCN2+, Co(NH,),SCN2+, and trans-Co en,(SCN)2+.34 Formation constants have been determined for the complexes of methyl, isopropyl, and other t ropolone~,~~ aminothiols leg. , NH,*CH,*CH,*SH), and di~ulphides,~~ azomethine and formazyl compounds with the uranyl ion,37 and with chromium, cobalt, nickel, and copper,38 and hydrazinedzacetic acid with the lanthan~ns.~O Group 1.-Pure lithium hydrogen sulphide (LiSH) has been prepared from lithium n-pentyloxide and hydrogen sulphide in ether solution. It is sensitive to hydrolysis and to oxidation, and decomposes to the sulphide and hydrogen sulphide above about 50". Thermal and X-ray data were obtained .40 A further series of ternary phosphides and arsenides of lithium have been prepared and subjected to X-ray analysis. These compounds, Li,SiP,, Li5SiAs,, Li,GeP,, Li,GeAs,, Li5TiP3, Li,TiAs,, Li,GaP,, and Li,GaAs,, are readily hydrolysed by water with formation of phosphine and arsine.41 A study of the slow formation and decomposition of the compounds between graphite and potassium (and rubidium) has revealed a whole series of compounds which differ in the number of graphite sheets between the 0 ...--H 11 (1) 2 6 F. Bas020 and R. K. Murmann, J . AuPzer. Chem. SOC., 1954, 76, 211. 2 7 F. Basolo and Y . T. Chen, ibid. , p. 953. 28 F. Basolo, Y . T. Chen, and R. K. Murmann, ibid., p. 956. 29 M. Haissinsky, J . Phys. R a d i u m , 1946, 7, 7. 30 D. Chapman, Nature, 1954, 174, 887. 31 Anw. Reflorts, 1953, 50, 89 ; see also K. J. P. Williams, J . Phys. Chenz., 1954,58, 121. 32 G. L. Eichhorn and R. A. Latif, J . Arpzer. Chem. SOL, 1954, 76, 5180. 33 B. E. Bryant and W. C. Fernelius, ibid. , p. 5351. 34 A. W. Adamson and R. G. Wilkins, ib id . , p. 3379. 35 U. E. Bryant and W. C. Fernelius, ibid. , pp. 1696, 3783. 3G E. Gonick, W. C. Fernelius, and B. E. Douglas, ibid., p. 4671. 3 7 M. Seyhan, B e y . , 1954, $7, 396. 38 R. Wizinger, 2. Naturforsch., 1954, 9b, 729. 40 R. Juza and P. Laurer, 2. anorg. Chenz., 1954, 275, 79. 41 R. Juza and W. Schulz, ;bid., p. 65. 30 R. C. Vickery, J. , 1954, 385. Pu bl is he d on 0 1 Ja nu ar y 19 54 . D ow nl oa de d by U ni ve rs ity o f C al if or ni a - R iv er si de o n 29 /1 0/ 20 14 1 7: 30 :3 3. View Article Online http://dx.doi.org/10.1039/ar9545100118 122 INORGANIC CHEMISTRY. layers of alkali-metal atoms. The maximum alkali-metal content, in C,K, is reached when alternate layers are carbon and potassium, but when there are 2, 3, 4, or 5 graphite layers between each potassium layer the ideal formulae are C,,K, C3,K, C4,I COATES AND GLOCKLTNG. 123 extensively in some solvents, the monomeric units (R,P) CdI, again requiring a metal covalency of three.% Group 11.-Hot-stage microscopy has been used to examine the poly- morphism and transition temperatures of sodium tetrafluoroberyllate, Na,BeF,; there are five solid forms of this salt.55 Lithium sodium tetra- fluoroberyllate, LiNaBeF,, prepared by slow evaporation of the aqueous solution, has strong crystallographic resemblance to monticellite, CaMgSiO,. 56 The vapour pressure of beryllium fluoride has been measured, and leads to an extrapolated boiling point 1159" (m. p. -803°).57 The complexity of aqueous solutions of beryllium salts has long been recognised, though the nature of the polynuclear ions which must be present has never been clarified. Recent pH measurements on beryllium perchlorate solutions at constant ionic strength have shown that a description of the system by means of only a few ionic species is incomplete; for the two simplest types (hydration being ignored) 58 [BeOH+][Hf]/[Be2'] = (0-3 5 0-1) x [Be,0H3+][H*]/[Be2+]2 = (0-31 & 0.06) x Methods have been developed for interconverting normal and basic Slow sublimation of the normal carboxylic acid derivatives of beryllium. salts leads to the basic derivatives : 4Be(O,C*H), = Be,O(O,C*H), + H,O + 2CO ~ B ~ ( O A C ) ~ = Be,O(OAc), + Ac,O The normal salts result when the basic derivatives are heated with a mixture of acid chloride and acid, e.g., Be,O(OAc), + 2AcCl+ 2AcOH = 4Be(OAc), + 2HC1 + Ac,O but the normal formate is obtained simply from anhydrous formic acid and the oxide or basic acetate.59 The chemistry of beryllium has been extended to diisopropylberyllium, m. p. -9.5", which is dimeric in benzene solution and forms a monomeric co-ordination compound with trimethylamine (involving a covalency of three for the beryllium). On thermal decomposition it affords propylene and the polymeric half-hydride (Me,CH*BeH),. Reaction with dimethyl- amine gives first dimethylaminoisopropylberyllium, which decomposes thermally to another polymeric half-hydride (Me,N*BeH),, and finally the fully methylat ed beryllium nitride 6o [Be (NMe,) ,I3. Di-tert. -bu tylberyllium, from the chloride and tert.-butylmagnesium chloride, loses isobutene very readily, yielding at -210' beryllium hydride containing a small amount (-4 moles yo) of alkyl group : (Me,C),Be = BeH, + 2Me,C:CH, 54 R. C . Cass, G. E. Coates, and R. G. Haytcr, Chem. and Itid., 1964, 1485. 56 W. Jalin and E. Thilo, 2. anorg. Chem., 1953, 274, 7 2 . 56 W. Jahn, ibid., 1954, 276, 113. G 7 K. A. Sense, M. J. Snyder, and J. W. Clegg, .[. Phys. Chew., 1954, 58, 233. 58 G. Mattock, .J. Amer. Chem. SOG., 1954, 76, 4835. 59 H. Hendus and H. D. Hardt, 2. anorg. Chew., 1954, 277, 127; J. Besson and II. D. Hardt, ibid., p. 188. 6o G. E. Coates and F. Glockling, J . , 1954, 22. Pu bl is he d on 0 1 Ja nu ar y 19 54 . D ow nl oa de d by U ni ve rs ity o f C al if or ni a - R iv er si de o n 29 /1 0/ 20 14 1 7: 30 :3 3. View Article Online http://dx.doi.org/10.1039/ar9545100118 124 INORGANIC CHEMISTRY, Beryllium hydride thus prepared is stable up to -240-290", and decom- poses rapidly at 300"; it gives the nitride derivative [Be(NMe,),], with dimethylamine. 61 Magnesium boride, prepared from the elements a t 800" in a hydrogen atmosphere, has the formula MgB, (not Mg,B,) and is isomorphous with A1B,.62 Three other crystalline phases exist, one being MgB4.63 Electrolysis studies using magnesium electrodes in a divided cell con- taining various aqueous salt solutions have provided some evidence for the existence of Mg+ ions; this is based on measurements of anodic dissolution rates.64 X-Ray diffraction has shown that the grey subchloride of calcium, CaCl, obtained by heating calcium metal and CaC1, in equivalent proportions to lOOO", is evidently an individual substance and not a mixture of Ca + CaCl,. In the presence of nitrogen transparent red crystals of the composition Ca,NCl are formed when calcium metal and CaCl, are heated together. 65 The reaction of calcium with water vapour in the range 177-369" proceeds by three consecutive steps : G6 2Ca + H20 = CaO + CaH, CaH, + 2H,O = Ca(OH), + ZH, CaO + H,O = Ca(OH), The pH of phosphate and citrate buffer sohtions is markedly reduced by the addition of calcium ions, on account of the formation of association products (ion pairs). Dissociation constants in water a t 25" are reported for CaH,PO,+, CaHPO,, CaH,Cit+, and CaHCit.67 Solubility studies on calcium phosphate solutions have been recorded,68 and the binary systems Sr(ClO,),-H,O, Sr(BrO,),-H,O, and Sr(IO,),-H20 have been in~es t iga t ed .~~ The barium salts of alloxantin, its tetramethyl derivative, and hydr- indantin are coloured deep blue or blue-violet. These compounds have been considered to be free radicals related to the metal ketyls, but magnetic experiments have convincingly shown the absence of radicals. 70 The equilibrium constant for the reaction Hg(1iquid) + Hg++ = Hg2++; K(25") = 83-4 has been measured from 0" to 40" a t various ionic strengths, together with heat and entropy data.71 The composition of the precipitate resulting from the addition of ammonia to aqueous mercuric bromide is rather sensitive to the ammonia concentration. Pure HgNH,Br is formed when the ammonia is between 0.07 and 0 . 0 9 ~ ; at higher concentrations some mercuric bromide 61 G. E. Coates and F. Glockling, J. , 1954, 2526. 62 M. E. Jones and R. E. Marsh, J . Amer. Chem. SOC., 1954, 76, 1434. 63 J. Russell, R. Hirst, F. A. Kanda, and A. J. King, Acta Cryst., 1933, 6, 870. 64 K. L. Petty, A. W. Davidson, and J. Kleinberg, J . Amer. Chem. Soc., 1854,76, 363. 6 5 G. Wehner, 2. anorg. Chem., 1954, 276, 72. 6 6 D. S. Gibbs and H. J. Svec, J . Amer. Chem. SOC., 1953, 75, 6052. 67 C . W. Davies and B. E. Hoyle, J., 1953, 4134. 6 8 J. D'Ans and R. Kniitter, Angew. Chem., 1953, 65, 578. 69 W. F. Linke, J . Amer. Chem. SOG., 1953, 75, 5797. 7 0 R. W. Asmussen and H. Soling, Acta Chenz. Scand., 1954, 8, 558. 7 1 G. Schwarzenbach and G. Anderegg, Helv. Chim. Ada , 1954, 37, 1,089. Pu bl is he d on 0 1 Ja nu ar y 19 54 . D ow nl oa de d by U ni ve rs ity o f C al if or ni a - R iv er si de o n 29 /1 0/ 20 14 1 7: 30 :3 3. View Article Online http://dx.doi.org/10.1039/ar9545100118 COATES AND GLOCKLING. 125 is held in solid solution.72 The nuclear magnetic resonance spectrum of infusible white precipitate shows that the protons are arranged in pairs, in support of the structure HgNH,Cl containing -Hg-NH,-Hg-NH,- chains, and excluding structures such as NHg,Cl,NH,Cl, or xHgO,(l - x)HgCl2,2NH, in which protons are arranged in threes or One of the numerous basic chlorides of mercuryhas been shown, by X-ray analysis, to be an oxonium salt [O(HgCl),]Cl. The three O-Hg-C1 bonds are collinear, but the three O-Hg bonds are apparently in one plane.74 Addition of mercurous nitrate solution to dilute potassium ferricyanide pre- cipitates the salt KHg,[Fe(CN),] ; reverse addition gives (Hg,),[Fe(CN),],.75 Group 1x1.-The existence of two new hydrides of boron has been con- firmed. The presence of octaborane, B&2, had earlier been suspected in residues from the decomposition of the unstable pentaborane B5Hl, ; 76 its existence, and that of nonaborane," B9H13, have been confirmed by mass- spectrographic methods. 78 Similar methods have been used to investigate the hydrolysis of stable pentaborane by water bound in silica gel. The first step appears to be the formation of the tetraborane B,H, by removal of a borine (UH,) fragment and its subsequent hydro ly~ i s .~~ A number of metal borohydrides may be conveniently prepared by metathetical reactions between sodium borohydride and the appropriate metal chloride in ethanol below Oo,80 e.g., 2NaBH, + MgCl, = Mg(BH,), + 2NaCl Alkali-metal borohydrides have also been obtained by the reaction (in methanol) ,81 -t- 4- NaBH, + MOMe = MBH, + NaOMe (M = K, Rb, CS) The preparation of sodium trimethoxyborohydride, from methyl borate and sodium hydride in tetrahydrofuran, has been improved. Its properties as a reducing agent for organic compounds have been studied.82 Interesting compounds containing arsenic-boron bonds have been described; these are formed from diborane and both arsine and its methyl derivatives. The compounds initially formed, e.g., AsMeH,,EH,, are less stable than the corresponding phosphorus compounds, but in common with them show an increase in stability with methylation. Diborane and arsine or methylarsine give polymeric products corresponding to the compositions (H,As~BH,). and (MeAsHaBH,),, but the reaction between diborane and dimethylarsine led to the isolation of tri-, tetra-, and poly-meric forms of (M~,AS*BH,),.~ Diborane and dimethyl sulphide form a fairly stable compound Me,S,BH, in contrast to the low stability of MeSH,BH, and the non-existence of H,S,BH,. The second compound readily loses hydrogen to 72 I 126 INORGANIC CHEMISTRY. forin polymers (MeS*BH,), which give a liquid adduct (m. p. 14") with tri- methylamine, Me3N,BH,-SMe.s4 Work on boron-sulphur ring compounds has been extended by the isolation of rnethoxyboron sulphide (MeOBS), from metathioboric acid (HS*BS), and methyl borate. The corresponding dimethylamino-compound has also been described. 85 Difficulties involved in the preparation of borazole by reduction of the readily obtainable B-trichloroborazole have been discussed : B6 3LiBH4 + B,N,H,CI, = B,N,H, + $B,H, + 3LiC1 Reactions of boron trifluoride in which B-F bonds are broken have been further investigated and, a t least in certain cases, boron trifluoride adducts are isolable intermediates. Dimethylaminodimethylborine, Me,N*BMe, forms with boron trifluoride the adduct Me,N-BMe,,BF, which at low tem- peratures dissociates into its components in a vacuum. But a t 0" or above, reaction occurs to give almost exclusively Me,BF and Me,N*BF,. The latter is monomeric and not dimeric as previously reported. With tri- methylamine it forms bisdimethylaminoboron fluoride : g7 2Me,N*BF2 + Me,N + (Me,N),BF + Me,N,Blt;, Vapour pressure-composition studies on the system BF,,NH3 have shown that at low temperatures the compounds (NH,),BF,, (NH,),BF,, and (NH,),BF, exist. It is suggested that in the stable compound &H3-EF3 the hydrogen atoms are sufficiently acidic to co-ordinate up to three additional molecules of ammonia. Dimethylamine only forms the 1 : 1 complex between 0" and --64".88 Boron trifluoride co-ordinates very strongly with the nitrogen atoms in bisdimethylamine sulphide, giving (Me,N),S,2BF3, and less strongly with ( Me2N),S0. The corresponding sulphone, (Me,N),SO,, only co-ordinates weakly with boron trifluoride. This is the order of stability expected owing to the inductive effect of the oxygen The tetrahydrofuran complex of boron trifluoride forms bi-complexes with ethylenediamine and hexa- methylenediamine, F,B,NH,*[CH,],*NH,,BF, (n = 2 or 6) A number of 1 : 1 compounds are reported between ethers and boron trifluoride. Dioxan also forms the complex C4H,02,2BF,.91 The Raman spectrum of dimethylaminodichloroborine, Cl,B*NMe,, indicates that the B-N bond is essentially a double bond (in the monomer). A more convenient preparative method has been devised, from boron tri- chloride and trisdimethylaminoboron, B(NMe,),.92 Tri-ut-propylboron and iodine react above 140" to give mainly di-n- propyliodoboron, which undergoes halogen exchange with antimony chloride or bromide.g3 84 A. E. Burg and 13. I. Wagner, J . Amev. Chem. SOC., 1964, 76, 3307. 8 6 E. M7iberg and W. Sturm, Z. Naturforsch., 1953, Sb, 689. 8 6 R. Schaeffer, M. Steindler, L. Hohnstedt, H. S . Smith, L. B. Eddy, and H. I. Schlesinger, ,I. Amer. Ghcm. SOC., 1954, 76, 3303. A. B. Burg and J. Ranus, ibid. , p. 3903. s 8 H. C. Brown and S. Johnson, ibid. , p. 197s. 89 A. B. Burg and H. W. Woodrow, ibid., p. 219. YO C. -4. Brown, E, L. Muetterties, and E. G. Rochow, ibid. , p. 2637. 91 J. Grimleyand A. I COATES AND GLOCKLING. 127 The preparation of diboron tetrachloride has been improved and interest- ing reactions of this compound are reported. Above 0" it partially decom- poses into B,Cl, and rather ill-defined products. With hydrogen a t room temperature in the absence of a catalyst diboron tetrachloride forms diborane and boron trichloride, probably by disproportionation of B,Cl,H,. The initial reaction with lithium borohydride is probably B,Cl, + 4LiBH, = B,H1, + B,H, + 4LiCl other boron hydrides being produced by secondary reactions. Ether forms a dietherate, in contrast to trimethylamine which gives a stable tetramer [B2C1,,2NMe,],. Diboron tetrachloride and ethylene form the compound Cl,B*C,H,*BCl, in which the B-B bond has evidently been broken since no hydrogen is produced with sodium hydroxide. The chlorine atoms in the ethylene compound can be replaced by methoxy-groups by means of meth- anol, giving (MeO),BC,H,*B(OR!le),, or by methyl groups with dimethyl- zinc, forming Me,B*C,H,*BMe,. Pyrolysis of Me,B-C,H,*BMe, resulted in cleavage of methyl groups as trimethylboron, and conditions were estab- lished whereby 75% or 100% of the methyl groups present formed tri- methylboron. Fairly volatile liquids and polymeric products were formed in each case, to which the following structures have been assigned : 94 Boron tricyanide, B(CN),, m. p. 146.5", has been isolated by sublimation froin a mixture of silver cyanide and boron trichloride which had remained at room temperature for forty years. The reaction is still very slow a t 60" and polymerisation takes place readily a t higher temperatures. Boron cyanide is said to be very The presence of polyborate ions in concentrated aqueous solutions of boric acid is indicated by pH measurements. The observed acidities agree with calculated values based on the assumption of a singly dissociated trimer and a singly dissociated h e ~ a m e r . ~ ~ Some dialkylboronic acids, R,B*OH, have been prepared by Grignard reaction^.^' Boron acetate, prepared in several different ways, has tlie composition corresponding to the " pyroacetate " : 2B(OH), + 5Ac20 = (AcO),B*O*B(OAc), + 6AcOH and not the noriiial acetate as sometimes supposedb98 The preparation of calcium aluminium hydride, Ca(AlH,),, from alu- minium chloride and finely divided calcium hydride in tetrahydrofuran has been described. The product contains 40-50% of tetrahydrofuran.99 Some important reactions between a wide variety of oleiins and the alu- 94 G. Urry, T. Wsrtik, 13. E. Bloore, and H. I. Schlesinger, J . Anzer. Chem. SOC., !Iti 1 . 0. Edwards, J . -'lwei.. CJ~c?tt. SOC., 1953, 75, 6151. n 7 li. Id. I-etsiriger and I. Skoog, zbid., 1054, 16, 4174. W. Gerrard and 31. A. Wheelans, Ghem. apid Iiad., 1954, 758. )IT. Schwab and K. IX'intersberger, Z. ,hTafzufomch., 1963, Sb, 690. 19.34, '76, 52'33, 6299. y 5 M. Chaigneau, Coitapt. read., 1954, 239, 1220. Pu bl is he d on 0 1 Ja nu ar y 19 54 . D ow nl oa de d by U ni ve rs ity o f C al if or ni a - R iv er si de o n 29 /1 0/ 20 14 1 7: 30 :3 3. View Article Online http://dx.doi.org/10.1039/ar9545100118 128 INORGANIC CHEMISTRY. minium hydrides AlH,, LiAlH,, and Et,AlH have been reported. The diethylaluminium hydride used in this work was obtained from the chloride Et,AlCl and lithium or sodium hydride.100 Aluminium sulphide and selenide result from the reaction between trimethylaluminium and hydrogen sulphide or selenide ; the rather less reactive ether complexes give products containing methyl groups (or ethyl from Et,A1,0Et,).lo1 The presence of Al(OH),- ions in sodium aluminate solutions has been suggested in an investigation on the precipitation of crystalline aluminium hydroxide. lo2 Eight aluminium pentyloxides have been prepared from different pentyl alcohols and aluminium isopropoxide. All the aluminium alltoxides appear to be associated, the pentyloxides derived from primary alcohols being tetra- meric and those from secondary alcohols dimeric. The uteopentyloxy- compound is exceptional in being dimeric, and this is attributed to the steric requirements of the neopentyl group.lo3 Conflicting views on the compositions of complexes of aluminium bromide with various aromatic hydrocarbons have .been somewhat clarified. Vapour pressure-composition studies have revealed solid compounds Al,Br,, ArH with benzene and toluene, but not with m-xylene or mesitylene. However, both solution colours and molecular weights (in cyclopentane) indicate that similar complexes are formed by m-xylene and mesitylene. The compounds are formulated as 7;-complexes.104 Of interest in connection with the mechanism of Friedel-Crafts reactions, investigations of the complexes formed by the same four hydrocarbons with aluminium bromide and hydro- gen bromide have established the formation of carbonium-ion salts having the compositions [ArH,]+ [Al,Br,]- and [ArH,] + [AlBrJ, the former being the more stable. The stability of these complexes also increases with the number of methyl groups in the hydrocarbon. lo5 Aluminium halide-alkyl halide systems have been examined at temperatures between -78.5" and 0". At -78.5" aluminium bromide is monomeric in methyl bromide and forms a 1 : 1 addition compound in solution. At somewhat higher temperatures two solid phases occur, viz., MeBr,AlBr, and MeBr,AbBr,, but only the latter is present at -31.3". At 0" crystalline aluminium bromide separates. Aluminium chloride is dimeric in methyl or ethyl chloride, but aluminium iodide is monomeric in methyl iodide.lo6 Dissociation energies have been obtained for various 1 : 1 complexes between aluminium halides and several amines. The dissociation energy D(N-A1) is of the order 80 ltcal./mole for most of the complexes, the stability order being AlCl, > AlBr, > Al13, and pyridine > trimethylamine > ammonia.lo7 A new sodium aluminium fluoride, NaAlF,, has been obtained by passing a stream of inert gas over a mixture of sodium fluoride and aluminium fluoride at 1000" ; it is perceptibly volatile above 900°.108 100 K. Zieglcr, H. G. Gellert, H. Martin, K. Nagel, and J. Schneider, Annalen, 1954, lol K. Geiersberger and H. Galster, 2. aizorg. Chenz., 1953, 274, 389; see also E. lo3 R. C. Mehrotra, J . Indian Chent. SOL, 1954, 31, 85. Io4 H. C. Brown and W. J . Wallace, J . Amcr. Chenz. SOC., 1953, 75, 6265. lo5 Idem, ibid. , p. 6268. lo7 D. D. Eley and H. Watts, J. , 1954, 1319. lo8 E. H. Howard, J . Amev. Chem. Sot . , 1954, 76, 2041. 589, 91. Wiberg, BEY., 1942, 75, 2003. lo2 E. Herrmann, 2. anovg. Chem., 1053, 274, 81. Io6 Idem, ibid., p. 6279. Pu bl is he d on 0 1 Ja nu ar y 19 54 . D ow nl oa de d by U ni ve rs ity o f C al if or ni a - R iv er si de o n 29 /1 0/ 20 14 1 7: 30 :3 3. View Article Online http://dx.doi.org/10.1039/ar9545100118 COATES AND GLOCKLING. 129 Phase-rule studies have been reported on the systems Al,(S04),-H,0,109 Na,SO,-Al,(SO,),-H,O ,110 and Al,O,-P,O,-H,O. ll1 Anion-exchange experi- ments on the last system have indicated the presence of [A1(HP0,),I3- ions. Studies on several oxides in equilibrium with water at high temperatures and pressures have shown that scandium hydroxide, Sc(OH),, does not exist, but a well-crystallised salt ScO(0H) was obtained. The oxide S C , ~ , was the only other species detected. Thallic oxide afforded no hydrate but chromic oxide gave both CrO(0H) and Cr(OH),.l12 Following oxidation of cerium(1rr) and praseodymium(rI1) oxides by X-ray diffraction has shown that the oxides of the types Ce,O, and CeO, cannot depart appreciably from these compositions without the formation of a new phase. However, a phase of intermediate composition can have quite a wide range of oxygen content ; e.g., various oxides such as Ce40, and Pr,OIl, previously considered stoicheiometrically definite compounds, are particular examples of this single phase of variable composition. li3 Treatment of terbium and praseodymium oxides with oxygen a t up to 450" and 280 atm. has yielded light brown oxides of compositions TbO,.,, and PrO,.114 Terbium tetrafluoride has been obtained by the action of fluorine on terbium trifluoride at 320". It is monoclinic and structurally similar to the tetrafluorides of cerium, uranium, and thorium.l15 Lanthanons are displaced from their anionic complexes Ln enta- with ethylenediaminetetra-acetic acid by addition of cationic lanthanons. The lanthanon cations of higher atomic number and higher stability constant will displace from an anionic " enta '' complex a lanthanon of lower atomic number and stability constant. This method has been applied with some success to the problem of lanthanon separation.l16 The controlled hydrolysis of the trimethylgallium-ether complex leads to the formation of a trimeric dimethylgallium hydroxide (Me,Ga-OH),, which decomposes thermally to methane and an inert polymeric methyl- gallium oxide. 117 An amorphous and polymeric anhydride f (Me,Ga),O), is formed when a deficiency of water is used in the hydrolysis at a low tem- perature, and this is thermally much more stable.ll8 The solution phase in the systems gallium chloride-methyl halide (Cl, Rr, I) at low temperatures contains a 1 : 1 addition compound, while the solid phases (from methyl chloride) have the compositions MeCl,GaCl, and MeCl,Ga,Cl,. Halogen exchange between gallium trichloride and methyl bromide is slow (2% in 24 hours a t -80') and it has been suggested that the initial stage should be formulated RX + GaX, RX,GaX,, which may be followed by ionisation to R+GaX,-, as has been postulated in connection with Friedel-Crafts reactions. 119 The melting point of indium (156.17" -+ 0.05") has been recomniended log N. 0. Smith and P. N. Walsh, 1. Amer. Chem. Soc., 1954, 76, 2054. 110 J. A. Skarulis, H. A. Horan, and R. Maleeny, ibid., p. 1450. 111 13. F. Jameson and J. E. Salmon, J., 1954, 4013. M. TV. Shafer and R. Roy, 2. anorg. Chem., 1954, 276, 275. 113 G. Brauer and H. Gradinger, ibid., 1954, 277, 89. 114 TV. Simon and L. Eyring, J . Amer. Chem. SOC., 1954, 76, 5872. 115 B. B. Cunningham, D. C. Feay, and M. A . Rollier, ibid., 1954, 76, 3361. 116 R. C. Vickery, J., 1954, 1181. 117 M. E. Kenney and A. W. Laubengayer, .T. Amer. Chern. SOC., 1954, 78, 4839. 118 G. E. Coates and R. G. Hayter, persona1 communication. llS 13. C. Brown, L. P. Eddy, and R. Wong, J . Amer. Chem. SOC., 1953, 75, 6275. REP.-VOL. LI E Pu bl is he d on 0 1 Ja nu ar y 19 54 . D ow nl oa de d by U ni ve rs ity o f C al if or ni a - R iv er si de o n 29 /1 0/ 20 14 1 7: 30 :3 3. View Article Online http://dx.doi.org/10.1039/ar9545100118 130 INORGANIC CHEMISTRY. as a useful temperature for thermocouple calibration, since indium can now be obtained in a state of high purity.120 Group 1V.-Minute concentrations of methyl radicals are apparently formed in the decomposition of tetramethylammonium amalgam, as shown by the removal of tellurium mirrors : 121 Me,N --+ Me,N + Me. The polymeric and highly stable substance, paracyanogen, results from the decomposition of oxamide. I ts infrared spectrum is compatible with the structure (11), which involves no great distortion of bond angles.122 (11) Cyanogen chloride forms 1 : 1 addition compounds with a number of metal chlorides (Au3+, B, Al, Fe3+, Pt4+) and conductivity studies on these double halides dissolved in cyanogen chloride provide evidence for the existence of a positive cyanogen ion in solution, e.g., CNCl,AlCl, + CN+ + RlCI,-. The conductivities of liquid cyanogen halides are explained in terms of dissociation to free halogens and also by self-i0ni~ation.l~~ There is some evidence for the formation of free silicon in a particularly active form during oxidation of the various calcium silicides. These observ- ations agree with the strong reducing properties of metal silicides even at moderate temperatures. Thus even titanium(1v) oxide is reduced by CaSi below 700", forming TiSi, and Ti,Si,.lX If a cold finger is placed above a mixture of silicon and silica a t 1200-1500" in a vacuum, a new form of silica, " fibrous silica," is deposited as well as silica, silicon, and silicon monoxide. This form of silica (density 1.96-1.98 ; m. p. -1420") has a chain structure similar to that of silicon disulphide. When heated at 200-800" it slowly changes to tridymite, and to cristobalite a t 1390". It is hydrated to amorphous silica by water vapour, and to meta- silicic acid by liquid water.125 Of the silylamines SiH,-NMe,, (SiH,),NMe, and (SiH,),N, only SiH,*NMe, co-ordinates with trimethylboron, the heat of dissociation of the complex being about 6.5 kcal./mole. The decrease in electron-donor properties in the above series is attributed to partial double-bond character in the Si-N bonds.126 Silane and phosphine when heated in a sealed vessel a t 450" form the monomeric compound 12' SiH,*PH,. The complex reactions between silane and unsaturated hydrocarbons at 450-510" are explicable by assuming the formation of SiH, radicals as the primary step : From ethylene the main products are ethyl- and diethyl-silanes.128 Some acetylene derivatives of silicon, tin, and lead of the type exemplified by Et,Sn*CiC*SnEt, have been prepared by The yield is very small. SiH, _t SiH, + H. 120 S. Valentiner, Z. anorg. Chem., 1954, 277, 201. 121 G. B. Porter, J . , 1954, 760. 122 L. I,. Bircumshaw, F. M. Tayler, and D. H. Whiffen, J. , 1954, 931. 1 2 3 A. A. Woolf, J. , 1963, 4121; 1954, 252. 124 A. Chrktien, W. Freundlich, and M. Bichara, Cow@. rend., 1954, 239, 1046, 1141. 125 A. Weiss and A. Weiss, Z. anorg. Chem., 1954, 276, 96. 126 S. Sujishi and S. Witz, J . Amer. Chem. SOC., 1954, 76, 4631. 1 2 7 G. Fritz, Z . Natzqforsch., 1953, 8b, 776. 128 D. G. White and E. G. Rochow, J . Anzer. Chem. SOC., 1954, 76, 389i. Pu bl is he d on 0 1 Ja nu ar y 19 54 . D ow nl oa de d by U ni ve rs ity o f C al if or ni a - R iv er si de o n 29 /1 0/ 20 14 1 7: 30 :3 3. View Article Online http://dx.doi.org/10.1039/ar9545100118 C0.4TES AND GT,OCKT,ING. 131 several methods. Although the silicon compounds are unusually stable, yet the tin and more particularly the lead compounds are readily hydrolysed and are decomposed by cuprous and silver ions.129 Improved methods have been devised for the preparation of mono- and di-chlorosilanes in about 85 and 1576 yields respectively. Silicon tetra- chloride and formaldehyde are passed over a y-alumina catalyst a t 400- 450" : 130 SiCl, + 3H2C0 = SiH,Cl + 3HC1 + 3CO SiCl, + 2H2C0 = SiH2Cl, + 2HCl + 2 C 0 The isothermal dehydration of silicic acid prepared by the action of damp air on silicon disulphide clearly indicates a tetrasilicic acid H8Si,01, to which a ring structure is assigned. Dehydration by dioxan and by sulphuryl chloride provides less definite evidence for other silicic acids.131 Methyl orthosilicate cannot be obtained by the addition of silicon tetrachloride to methanol since it is immediately hydrolysed by water derived from hydrogen chloride and the excess of methanol. A good yield of the ortho-ester can be obtained by the reverse addition. The hydrolysis and disproportionation of these esters have been studied, and some di-, tri-, and tetra-silicic acids prepared.1332 That silicon can be transported in a stream of silicon tetrachloride has been known for some time,133 but numerous subchlorides might be respon- sible. A quantitative examination of the variation of pressure with temper- ature of silicon tetrachloride in equilibrium with silicon has shown that the reaction is Si + SiCl, _t 2SiC1,. Thermodynamic data have been obtained for this reaction, which becomes appreciable only above about 1100". The thermal decomposition of SKI, into SiC1, and chlorine takes place to a much smaller extent. l34 An interesting series of compounds is reported containing alternate Si-Siand Si-0-Si linkages formed by partial hydrolysis of Si,Cl, at -78". So far, three pure compounds have been isolated : 135 Si40C1,,( Cl3Si*SiC1,*0*SiC1,*SiC1,), Si,O,Cl,, , and Sis03Clls. Ammonolysis of hexachlorodisiloxane, Si,OCl,, leads to the formation of (Si,ON,H,) which, on pyrolysis, forms silicon oxy- nitride, (SiON,),, slightly contaminated with ~ i 1 i c a . l ~ ~ Silicon tetrahalides form a variety of complexes with pyridine and related compounds. These generally are of the type SiX,,Bpy, but silicon tetraiodide adds four moles of base. The formation of these complexes was followed by a simple method of calorimetric titration. The complexes are all water-sensitive, and decom- pose without melting when heated. 13' Chlorosilanes and trimethylamine form very weak 1 : 1 complexes. A comparison of the stabilities of these adducts indicates that the steric effect of the chlorine atoms predominates The existence of definite silicic acids has been a matter of dispute. 129 C. Beermann and H. Hartmann, Z. anorg. Ckem., 1954, 276, 20. I3O 0. Glemser and W. Lohmann, ibid. , 1954, 275, 260. lJ1 R. Schwarz, ibid., 1954, 276, 33. 132 R. Schwarz and K. G. Knauff, ibid., 1954, 275, 176. lJ3 L. Troost and P. Hautefeuille, Ann. Cham. phys., 1876, 7, 469. p. 265 ; P. F. Antipin and V. I-. Sergeyev, Zhztr. priklad. Khinz., 1954, 27, 784. 135 W. C. Schumb and R. A. Lefever, J . Amer. Chenz. Sor., 1954, 76, 2091. 136 Idem, ibid., p. 6882. lS7 U. Wannagat, R. Schwarz, H. Voss, and K. G. Knauff, Z. anorg. Chevz., 1954, H. Schafer and J. Nickl, 2. anorg. ChenL., 1953, 274, 250; H. Schiifer, ibid., 277, 73. Pu bl is he d on 0 1 Ja nu ar y 19 54 . D ow nl oa de d by U ni ve rs ity o f C al if or ni a - R iv er si de o n 29 /1 0/ 20 14 1 7: 30 :3 3. View Article Online http://dx.doi.org/10.1039/ar9545100118 132 INORGANIC CHEMISTRY. over its electronegativity effect, which should increase the strength of the N-Si bonding. 138 Silicon tetrachloride and ammonia, a t high temperatures (825"), yield two volatile products : a liquid iminochloride, Si,(NH)Cl,, and a crystalline compound which is probably a cyclic tetramer, Si,N,C1,0.139 Dimethyl- formamide co-ordinates by its nitrogen atom with silicon tetrafluoride, form- ing SiF,,H*CO*NMe,, which shows the characteristic CO absorption in the infrared. 140 Several new biscyclopentadienyl salts of titanium-(111) and -(Iv) and of zir- conium(1v) have been described. The zirconium(1v) bromide, (C5H5)?,ZrBr2, which is colourless and diamagnetic, could not be reduced to a zirconium(rr1) compound.141 If tetrapropoxytitanium in propyl alcohol is added to potassium a precipitate having the composition (PrO),Ti is formed. In the presence of air this forms the dialkoxytitanium oxide (PrO),TiO. Analogous butyl compounds are reported. 142 Tetra-tert.-butyl titanate complexes with several diols have been examined by cryoscopic measurements in tert.-butanol. A product having a titanium : glycol ratio of 2 : 3 is strongly suggested, and evidence for other complexes having 2 : 2, 2 : 4, and 3 : 6 ratios has been obtained.I& TitaRium trifluoride has been prepared by various methods, but most satisfactorily from titanium hydride and hydrogen fluoride at 700". It forms a blue solid which can be purified by sublimation in a vacuum at 950°, and is remarkably stable to air, water, and even concentrated sulphuric acid. Its magnetic susceptibility (1.75 B.M.) is appropriate for the Ti3+ ion.144 The well-known yellow colour obtained when hydrogen peroxide is added to acidified Ti(Iv) solutions was for some time thought to be H,[TiO,(SO,),]. The test, however, is equally sensitive in acids other than sulphuric, and anions have been shown to be absent from the complex, Ti02+-H,02, which is positively charged (dissociation constant 5 x Decomposition studies on M,TiCl, have led to heats of formation for the reaction 2MC1 4- TiCl, + M,TiCl, of 35 and 27 kcal. per mole for the rubidium and the potassium compound respectively. 146 Vapour-pressure measurements on zirconium dioxide give A HVaP. = 153-6 3: 1 kcal./mole. The heat of dissociation of ZrO,(g) into gaseous atoms is 365 rf 5 k~a l . /mo le . l~~ Zirconium and hafnium tetrachlorides form complexes with diethyl phthalate and other esters.143 The amidochloride ZrNH,Cl, is obtained from ZrC14 and ammonia in contrast to the behaviour of thorium tetra- chloride which only forms an unstable addition complex. 149 145 1 3 8 A. B. Burg, J . Amer. Chem. SOL, 1954, 76, 2674. 139 W. C. Schurnb and L. H. Towle, ibid., 1953, 75, 6085. 140 T. S. Piper and E. G. Rochow, ibid., 1954, 76, 4318. 1 4 1 G. Wilkinson and J. M. Birmingham, ibid., p. 4281. 1 4 2 A. N. Nesmeyanov, 0. V. Nogina, and R. K. Freidlina, Doklady Akad. X u u k 143 R. E. Reeves and L. W. Mazzeno, J . Amer. Cltem. SOC., 1954, 76, 2533. 1 4 4 P. Ehrlich and G. Pietzka, 2. anorg. Chenz., 1954, 275, 121. 1 4 5 E. Gastinger, ibid., p. 331 ; see also R. Schwarz, ibid., 1933, 210, 303. 1 4 6 P. Ehrlich and E. Framm, 2. Naturforsch., 1954, gb, 326. 1 4 7 M. Hoch, M. Nakata, and H. L. Johnston, J . Amer. Chem. SOC., 1954, 70, 2661. 1 4 8 R. V. Moore and S. Y . Tyree, ibid. , p. 5253. 3 4 9 G. W. A. Fowles and F. H. Pollard, ,I. , 1953, 4128. S.S.S.R., 1954, 95, 813. Pu bl is he d on 0 1 Ja nu ar y 19 54 . D ow nl oa de d by U ni ve rs ity o f C al if or ni a - R iv er si de o n 29 /1 0/ 20 14 1 7: 30 :3 3. View Article Online http://dx.doi.org/10.1039/ar9545100118 COATES AND GLOCKLING. 133 An improved method for the purification of zirconium and hafnium oxides has been described involving crystallisation of the sulphate tetra- hydrate.150 The hafnium silicides HfSi and HfSi, have been prepared by direct combination of the elements.151 In contrast to the other group IVA metals thorium tetrachloride reacts with the lower alcohols to form tetra-alcoholates of the type ThC1,,4ROH.152 Investigations of the alkoxides of group IVA metals have now been extended to the hitherto-unknown thorium alkoxides. The isopropoxide, obtained from ThC1,,4PriOH and sodium isopropoxide, had a degree of association of 3.8 and 1.8 in benzene and isopropyl alcohol, respectively, and could be sub- limed at 200" in vacuo. The methoxide and ethoxide were obtained from the isopropoxide by alcohol-exchange reactions ; both were involatile and insoluble in benzene. Those tetra-alkoxides Th(OR), having more complex alkoxy-groups (e.g., R = CMe,, CEt,) are liquids of low volatility. Their molecular weights in boiling benzene show degrees of association varying from unity (R = CEt,, CMeEtPr') to 3.4 when R = CMe,. This behaviour agrees with that found for other group IV metal alkoxides for which the molecular complexity is determined essentially by the size and shape of the alkyl group. 153 Thorium nitrate forms stable tetra- and penta-hydrates at 25", and an anhydrous solid, isolated from the low water region,l= had the composition Th(N0J4,2HNO3. Thorium nitrate and sodium citrate at pH 3 form the soluble complexes Th,Cit, in aqueous solution and ThCit, in 50% ethanol. An insoluble product had the composition (ThCit),, and was soluble in excess of sodium citrate.155 Dimethyl- and triphenyl-germanes, Me,GeH, and Ph,GeH, have been obtained from Me,GeS and Ph,GeBr by reduction with zinc amalgam and hydrochloric acid.156 Tetramethoxygermane, (MeO),Ge, b. p. 146", has been prepared by the action of germanium tetrachloride on sodium methoxide in methanol (the corresponding reaction with SiC1, does not occur). Tetra- isopropoxygermane was obtained by alcohol exchange : (MeO),Ge + 4PriOH + (PriO),Ge + 4MeOH. Several poly-esters of germanic acid have also been prepared.15' Further work on the acid reduction of germanium dioxide using the minimum amount of hypophosphorous acid has led to the isolation of germanous hydrogen phosphite, GeHPO,, and the two complexes 3Ge(H,PO,),,GeI, and Ge,(P0,),,2GeHP04.158 When germanium tetrachloride vapour, mixed with an inert carrier gas, is heated to 900-1000" and suddenly cooled, a brown subchloride, (GeCl),, is formed. This is insoluble in all solvents, but is decomposed by alkali with evolution of hydrogen : 2GeCl+ 6KOH = 2K,GeO, -t 2KC1+ 3H, lS0 A. W. Henderson and K. B. Higbie, J . Amer. Chem. SOL., 1954, 78, 5878. 151 B. Post, F. W. Glaser, and D. Moskowitz, J . Chem. Phys., 1954, 22, 1264. 152 D. C. Bradley, M. A. Saad, and W. Wardlaw, J. , 1954, 2002. 163 Idem, ibid., pp. 1091, 3488. 15* J. R. Ferraro, L. I. Katzin, and G. Gibson, J . Amer. Chew. SOC., 1954, 76, 90'3. 156 M. Bobtelsky and B. Graus, ibid., p. 1536. lSa R, West, ibid., 1953, 75, 6080. lS7 R. Schwarz and K. G. Knauff, 2. anorg. Chem., 1954, 275, 193. 15* D. A. Everest, J., 1953, 4117. Pu bl is he d on 0 1 Ja nu ar y 19 54 . D ow nl oa de d by U ni ve rs ity o f C al if or ni a - R iv er si de o n 29 /1 0/ 20 14 1 7: 30 :3 3. View Article Online http://dx.doi.org/10.1039/ar9545100118 132 INORGANIC CHEMISTRY. Heating in a vacuum causes disproportionation : 500" 6GeC1-+ GeCl, + 4Ge f- GeCl, whereas only Ge and GeC1, result at a higher pressure. Small amounts of Ge,Cl, (m. p. 32") have been obtained by thermal decomposition of GeCl- GeC1, mixtures. The hexachloride is soluble in benzene, and dissolves in alkali with evolution of hydrogen. 159 Germanium iodide, GeI,, and diethyl- mercury react exothermically in benzene solution , forming ethane and butane as gaseous products. Mercurous iodide, Hg,I,, EtHgI, and GeEt, were also isolated from the reaction mixture. Germanium iodide and di-n-butyl- mercury in acetone gave butylmercuric iodide and an oil considered to be Bu,IGe*GeIBu,. 160 Stannane is obtainable in 84% yield by the reduction of stannous chloride with sodium borohydride in acid solution.161 Tetrabutylstannane and stannic chloride disproportionate on warming, the main product being Bu,SnCl, which, with sodium ethoxide in ethanol, yields tetrabutyldichloro- dist annane, Bu,ClSn*SnClBu,. 162 Stannous oxide is more volatile than tin metal or stannic oxide; this is also true of GeO and SiO. The vapour pressure of SnO has been measured, and the condensate from SnO vapour consists of Sn, SnO, and Sn0,.163 A spectrophotometric and electromigration study on stannic ions in sulphuric acid has shown the following equilibria : Sn4+ + Sn(S04), __L H,Sn(SO,),. That involving H,Sn(SO,), only becomes appreciable in very concentrated sulphuric acid.164 Complex tartrates of tin, germanium, and titanium have been re-examined. Metal : tartrate ratios of 1 : 1 and 1 : 2 occur in each case.165 The lead-sodium compounds, K,PbNa, can be obtained by any of the following reactions in liquid ammonia : R,PbPbR, + 2Na __t 2R3PbNa R3PbC1 + 2Na+ R,PbNa 4- NaCl R4Pb + 2Na + R,PbNa + RH + NaNH, The relative merits of these methods have been discussed and the third reaction has been used to obtain Et,PbNa and Ph,PbNa. The reactivities of these two compounds towards alkyl halides have been studied. 166 A study of the basic lead azides has revealed the existence of five different species; in this connection the hydrolysis and solubility product (2.3 x loA9 a t 25") of lead azide itself has been investigated.16' Addition of sodium hydroxide to lead nitrate gives precipitates having the compositions Pb(NO,),,Pb(OH), and Pb(N0J2,5Pb(OH),. Lead hydr- oxide, Pb(OH),, is not precipitated.168 Normal and basic lead styphnate 159 R. Schwarz and E. Baronetzky, 2. anorg. Chenz., 1954, 275, 1. 160 G. Jacobs, Compt. rend., 1954, 238, 1825. 161 G. W. Schaeffer and M. Emilius, J . Amer . Chem. SOC., 1954, 76, 1203. 162 0. H. Johnson and H. E. Fritz, J . Org. Ckewz., 1954, 19, 74. lti3 H. Spandau and T. Ullricli, 2. nnorg. Chern., 1953, 274, 271. 1 6 4 C. H. Brubaker, J . Amw. Chenz. SOC., 1954, 76, 4269. 165 G. Mattock, J. , 1954, 989. 166 H. Gilman and E. Bindschadler, J . Org. Chern., 1953, 18, 1675. 167 W. Feitknecht and M. Sahli, Helv. Chim. A d a , 1954, 37, 1423, 1431. J . L. l'auley and M. R. Testerman, J . d m w . Chew. Sac., 1954, 76, 4220. Pu bl is he d on 0 1 Ja nu ar y 19 54 . D ow nl oa de d by U ni ve rs ity o f C al if or ni a - R iv er si de o n 29 /1 0/ 20 14 1 7: 30 :3 3. View Article Online http://dx.doi.org/10.1039/ar9545100118 COATES AND GLOCKLLNG. 135 (2 : 4 : 6-trinitroresorcinol) have been prepared in a pure state, and their infra-red spectra examined.169 Group V.-From vapour-pressure measurements over a wide temperature range the maximum sublimation point of ammonium hydrogen carbonate has been estimated as 19.5".170 The reactions between chlorine and ammonia leading to the formation of hydrazine have received further extensive s t ~ d y . 1 7 ~ tert.-Butyl hypo- chlorite, like the alkali-metal hypochlorites, reacts with aqueous ammonia to give hydrazine. It has been suggested that the chloramine, formed as an intermediate, reacts with added base to give the chloramide ion NHC1- and imide as reactive intermediates : NHCL- NH + C1-; NH + NH3 = N2H4 Hydrazine is also formed from urea and tert.-butyl h y p ~ c h l o r i t e , ~ ~ ~ and good yields of alkylhydrazines have been obtained by application of the Raschig synthesis to primary aliphatic a m i n e ~ . l ~ ~ . There is some evidence that hydroxylamine is formed as an intermediate in the decomposition of chlor- amine by sodium h y d r 0 ~ i d e . l ~ ~ More salts of hydrazine, e.g. , with antimony and bismuth halides, have been de~c r ibed .~ '~ Improved laboratory preparations of several oxides of nitrogen in a state of high purity have been described.177 Anhydrous nitrates of weakly basic metals are difficult to prepare. Several of these, and some other salts, have been obtained by the electro- lysis of silver or copper nitrate solutions in methyl cyanide, anodes of the appropriate metal being used. Substances prepared by this general method include Co(N03),,3MeCN, Ni(NO,),,ZMeCN, Zn(N03),,2MeCN, Cd (NO,),,ZMeCN, and Sn( C10,) ,,ZMeCN. 178 Liquid dinitrogen tetroxide containing a tetra-alkylammonium nitrate dissolves zinc, giving a solution which contains the ions [Zn(N0,)4]2-, R4N+, and NO k. This is explained by the equilibrium : 179 (K4N) 2+ [Zn (NO,) 4]2- + 2N20, t;l (NO) ,+ [ Zn + 2 R4N*N0, The crystalline complex nitrate (EtNH,),,[Zn(NO,),] is formed when zinc dissolves in a solution of ethylammonium nitrate in dinitrogen tetroxide.lsO The ion-radical K,(SO,),NO acts as an oxidising agent to hydrazine, 4K,(SO,),NO + N2H4 = N, + 4K,(SO3)2NOH as well as to a variety of organic compounds. The reaction, which can be used for analytical purposes, is practically quantitative in alkaline solution and is, of course, accompanied by the disappearance of the deep violet IG9 R. A. Zingaro, J . A m e r . C h e m . SOG., 1954, 76, 816. l i 0 J. Zernke, Rec. Trav. chim., 1954, 73, 95. 171 H. H. Sisler, F. T. Neth, R. S. Drago, and D. Yaney, J . Amer. Chenz. Soc., 1954, 76, 3906, 3909, 3912, 3914. 172 L. F. Audrieth, E. Colton, and M. M. Jones, ib id . , p. 1428. 1 7 3 I d e m , ib id . , p. 2672. 1 7 5 R. E. McCoy, ib id . , p. 144'7. l i 7 R. E. Nightingale, A. K. Downie, D. L. Rotenberg, B. Crawford, and R. A . Ogg, J . Pliys. Chenz., 1954. 58, 1047. 1 7 8 H. Schmidt, 2. anorg. Chem. , 1953, 271, 305; see also i d e m , ibid. , 1952, 270, 188. 17Q C . C. Addison, N. Hodge, and R. Thompson, J. , 1954, 1143. 180 C. C. Addison and N. Hodge, ib id . , p. 1138. 174 I,. F. Audrieth and L. H. Diamond, ib id . , p. 4868. W. Pugh, J . , 1954, 1385. Pu bl is he d on 0 1 Ja nu ar y 19 54 . D ow nl oa de d by U ni ve rs ity o f C al if or ni a - R iv er si de o n 29 /1 0/ 20 14 1 7: 30 :3 3. View Article Online http://dx.doi.org/10.1039/ar9545100118 136 INORGANIC CHEMISTRY. colour of the radical.lSl I n a similar way hydroxylamine is oxidised to nitrous oxide in alkaline solution. During this investigation solutions of hydroxylamine hydrochloride were observed to decompose slowly on boiling.ls2 A detailed kinetic study indicates that the nitrite-azide reaction proceeds through the formation of nitrosyl cations : 183 NO,- + 2H,O+ = NO+ + 2H20 NO+ + N,- __t [NO-N,] __t N, + N,O The range of nitrosyl salts has been considerably extended, mainly by preparations carried out in anhydrous liquid sulphur dioxide solution. For example, nitrosyl methosulphate has been prepared by the two reactions : (a) NO*SbCI, + Me,N*MeSO, = NO*MeSO, + Me,N*SbC16 Fluorides react in liquid sulphur dioxide as if present as fluorosulphinate, S02F-, which gives nitrosyl fiuorosulphinate with a suitable nitrosyl salt : Me,NF -1 SO, + NO-HSO, = NO*S02F + Me,N*HS04 Many of the reactions studied have a bearing on the lead-chamber process and the Rctschig hydroxylamine synthesis.184 The tendency for nitrosyl chloride to ionise in the sense NO' + C1- is well known, and it has been found that complete and rapid exchange takes place between chloride ions and nitrosyl chloride : 185 Me,NS6C1 f- NOCl + Me4NC1 + N03%l A highly interesting series of metal azides is reported. The main pre- parative method involved the reaction between a metal hydride or alkyl and hydrazoic acid in ethcr or tetrahydrofuran, e.g., ( b ) MeONO + SO, = NO-MeSO, AlH, + 3HN3 = A1(N& + 3H2 A12Me, + 4HN3 = 2MeA1(N3), + 4CH4 Similarly, beryllium azide, Be(N,)2, and magnesium azide were prepared from dimethyl-beryllium and -magnesium, and Ga(N3), and B(N3), from Ga,H, and B,H6. In certain cases, by controlling the temperature, the reaction could be made to proceed in two stages; e g . , with lithium boro- hydride at -80" one mole of hydrogen is evolved corresponding to the reaction LiBH, + HN, = LiN, + 4B2H6 + H, and at 0" 3 moles of hydrogen are produced 4B2H6 + 3HN3 == B(N3)3 + 3H2 the overall reaction being LiBH, + 4HN, = LiB(N,), + 4H2 181 H. Gehlen, H. Elchlepp, and J. Cermak, 2. anorg. Chem., 1953, 274, 293. 182 H. Gehlen and G. Dase, i t i d . , 1954, 275, 327. 183 F. Seel and R. Schwaebel, zbid., 1953, 274, 169. 184 F. Seel and H. Meier, ibid., p. 190, 197. 1 8 5 J. Lewis and R. G. Wilkins, Chem. and Ind., 1964, 634. Pu bl is he d on 0 1 Ja nu ar y 19 54 . D ow nl oa de d by U ni ve rs ity o f C al if or ni a - R iv er si de o n 29 /1 0/ 20 14 1 7: 30 :3 3. View Article Online http://dx.doi.org/10.1039/ar9545100118 COATES AND GLOCKLING. 137 Aluminium a i d e and silicon azide were also obtained from the halide and sodium azide. Stannic azide, Sn( N,),, resulted from stannic chloride and sodium azide, but excess of the latter gave the salt Na,Sn(N,),. When the trirnethylamine compounds of aluminium hydride were allowed to react with hydrazoic acid, complex azides were obtained, e.g., [ Me,NH] + [ Al( N3) 4]- and [Me,N H I,+ [Al( N,) J2- All these azides are white solids and as might be expected are shock- sensitive and readily hydrolysed.ls6 The monolithium derivative of phosphine, LiPH,, has been prepared in good yield by adding phenyl-lithium to ether through which phosphine is passing. It is precipitated as a white powder, which has found use in the preparation of primary organic phosphines. The primary product of the reaction between sodium and yellow phos- phorus in liquid ammonia appears to be Na,H,P, + 2NaNH,, and not Na,P,. Filtration from insoluble sodamide gives, on concentration, an orange-yellow solid whose composition is nearly Na,H,P,. lS8 Phosphorus(v) oxide reacts slowly with isopropyl ether a t room temper- ature (also with boiling ethyl ether), forming mainly isopropyl esters of tetraphosphoric acids. These esters are very much more easily hydrolysed to lower phosphoric acids than the salts of the higher polyphosphoric acids.lsD Tetraphosphoric acid is a major product of the controlled hydrolysis of phosphorus(v) oxide, e.g., with damp ether. 190 A new phosphorus(v) oxychloride, P,04C11,, has been described. lgl The triamide of orthophosphoric acid, OP(NH,),, and its thio-analogue, SP(NH,),, have been prepared from phosphorus oxychloride (or PSC1,) and ammonia, both in chloroform solution : POCl, + 6NH3 = OP(NH,), + 3NH,Cl They are both crystalline solids, easily soluble in water with gradual hydro- lysis, and are monomeric in aqueous solution.192 Esters of hypophosphoric acid have been prepared by the action of powdered sodium on esters of phosphorochloridic acid : lse 2(RO),P(O)Cl + 2Na = (RO),(O)P*Y(O)(OR), + 2NaCl Ammonia dissociation-pressure measurements have shown that sesqui- ammonium orthophosphate, (NH4),H,(P04),, does not exist lS4 as previously claimed. lS5 Solubility relations in the system NaP03-H,O up to the melting point of NaPO, have been determined,196 and two new sodium phosphates have been E. Wiberg and H. Michaud, 2. Naturforsch., 1954, 9b, 495-503. 113’ N. Kreutzkamp, Chem. Ber., 1954, 87, 919. 188 P. Royen and W. Zschaage, 2. Naturforsch., 1953, 8b, 777. laB E. Thilo and H. Woggon, 2. anorg. Chent., 1954, 277, 17. loo E. Thilo and W. Wieker, zbzd., p. 27. 1 9 1 R. Klement, 0. Koch, and K. H. Wolf, Naturwiss., 1954, 41, 139. lB2 R. Klement and 0. Koch, B e y . , 1954, 87, 333. 193 M. Baudler, 2. Naturforsch., 1954, 9b, 447. 194 J. A. A. Ketelaar, H. J. Rundervoort, J. L. Lobatto, and F. N. Hooge, Rec. Trav. 1Q6 G. W. Morey, J . Amev. Cbem. Soc., 1953, 75, 5794. chim., 1954, 73, 662. A. de Passillk, Compt. rend., 1934, 199, 356; 1935, 201, 344. Pu bl is he d on 0 1 Ja nu ar y 19 54 . D ow nl oa de d by U ni ve rs ity o f C al if or ni a - R iv er si de o n 29 /1 0/ 20 14 1 7: 30 :3 3. View Article Online http://dx.doi.org/10.1039/ar9545100118 138 INORGANIC CHEMISTRY. isolated from the reaction between sodium dihydrogen phosphate and ort hophosphoric acid. lg7 The system PC1,-AlCl, shows a sharp eutectic corresponding to PCl,,AlCl,. Ion-transport experiments indicate that the complex is likely to be [PCl,]+[AlCl,]-. Ferric chloride behaves similarly, giving [PCl,]+ [FeC1,]-.lg8 Addition compounds are reported between the tri- and penta-chlorides of phosphorus, arsenic, antimony, and bismuth (trichloride) and triethylamine. All the halides form 1 : 1 addition compounds, but some interesting com- plexes having more than one mole of amine per mole of halide were also obtained. Of these,, the most definite were (Et,N),,PCl, and (Et,N),,AsCl,, which are stable white powders. No molecular weight, solubility, or con- ductivity data were reported. lg9 Tetramethylammonium chloride dissolves readily in arsenic trichloride, and a crystalline solvate [Me,N]+[AsCl4]-,2AsC1, can be isolated, which readily loses arsenic trichloride to give the previously known compound 2oo [Me,N] +[AsCl,]-. Ultraviolet absorption spectra have been used to identify the complexes present in solutions of antimony(v) in hydrochloric acid of varying concentration. The extent to which hydroxy-groups are replaced by chlorine in the series Sb(OH),Cl,-, increases with hydrochloric acid concentration.201 A number of ammines of bismuth(rI1) have been prepared, e.g., with quinoline and dimethylaniline.202 The hydrides and deuterides of niobium and tantalum have been prepared directly from the elements, and examined by X-ray diffraction. The maximum hydrogen uptake corresponds to the formulae NbH,.,, and TaHo..s.203 BiscycZopentadienylvanadium, (C,H,),V, has been prepared as a violet, paramagnetic solid. One of its most interesting reactions is with carbon monoxide, when the orange monomeric and diamagnetic compound C,H,V(CO), is formed.2a Several halides of biscyclopentadienyl- vanadium(m), -vanadium(Iv), -niobium(v), and -tantalum(v) have also been investigated. 141 Niobium and tantalum pentoxides, which form solid solutions, have different crystal lattices. The change of lattice form of the solid solutions has been measured in terms of temperature and composition.205 A number of borovanadites, or double oxides of boron and vanadium(m), have been obtained by electrolysis of fused salt mixtures at 900" ; these include MgBVO,, Fe,BVO,, and CO,BVO,.~~~ The Raman spectrum of vanadium oxychloride (VOCl,) indicates the presence of a double bond (VZO) ; similarly Re0,Cl contains ReZO bonds.207 There has recently been considerable interest in the electrical conductivity of anhydrous halides. The conductivities of niobium and tantalum penta- lg7 E. J . Griffith, J . Amer. Chem. SOC., 1954, 76, 5892. lo* Y. A. Fialkov and Y . B. Bur'yanov, Doklady Akad. Nauk S.S.S.R., 1953, 92, 585. lgO IV. R. Trost, Canad. j. Chenz., 1954, 32, 356. 2oo I. Lindqvist and L. H. Anderson, Acta Chem. Scand., 1964, 8, 128. 201 14. M. Neumann, J . Awier. Chem. Soc., 1954, 76, 3611. 202 N. hI. Turkevich, Zhur. obshchei Khim., 1954, 24, 978. 203 G. Erauer and K. Hermann, 2. anorg. Chent., 1053, 274, 11. 204 E. 0. Fischer and W. Hafner, 2. Nalurforsch., 1954, gb, 503. f06 P. Blum and H. Bozon, Complpt. rend., 1954, 239, 811. 207 H. J . Eichhoff and F. Weigel, 2. anorg. Chem., 1954, 275, 267. H. Schafer, A. Durkop, and M. Jori, Z . anorg. Chem., 1964, 275, 289. Pu bl is he d on 0 1 Ja nu ar y 19 54 . D ow nl oa de d by U ni ve rs ity o f C al if or ni a - R iv er si de o n 29 /1 0/ 20 14 1 7: 30 :3 3. View Article Online http://dx.doi.org/10.1039/ar9545100118 COATES AND GLOCKLING. 139 fluorides, which have positive temperature coefficients, are consistent with partial ionisation,208 e.g., 2NbF, __ NbF,+ + NbF,-. The vapour pressure of niobium(1v) chloride, from the metal and the pentachloride, has been measured between 300" and 370". The extra- polated sublimation point is 456", but above about 420" disproportionation occurs : 209 2NbC1, = NbCl, + NbCl,. The preparation and properties of the lower chlorides of tantalum, from tantalum pentachloride and aluminium, have been investigated more closely than previously.210 The tetrachloride, TaCl,, is deposited from the vapour as black crystals isomorphous with NbC1, ; it gives a brown solution in water, which evolves hydrogen. Readily oxidised, it is a stronger reducing agent than niobium tetrachloride. At about 280" it disproportionates into gaseous tantalum pentachloride and solid trichloride ; at higher temperatures the dichloride TaC1, is formed.211 Group V1.-The trioxides, M203, of the alkali metals have sometimes been believed to contain 0,2- ions, and sometimes been regarded as lattice compounds containing 0 2 2 - and 0,- ions. The absence of any infrared absorption by K203 excludes the presence of a bent triatomic ion 03,- and supports the view that it consists of a mixture of K20, and K20,.212 A mixed peroxide-superoxide of potassium and barium ( K2Ba06) has been isolated from the reaction between barium salts and potassium superoxide in liquid ammonia.213 It should be noted that violent explosions can occur when activated alumina is used to dry oxygen, if the alumina has previously been used to dry hydrogen. The paramagnetic resonance absorption spectrum of liquid sulphur supports the view that chain-type polymers rather than large rings are present in the A study of the potassium sulphides.has confirmed the existence of all the sulphides from K,S to K2S,.216 Potassium thus differs from sodium in that neither Na2S3 nor Na,S, could be prepared.217 Potassium hexasulphide (red crystals) does not give a clear solution in water, but is partly decomposed with the precipitation of sulphur. The pentasulphide appears to be the most stable member of the series. Measurement of the densities of these sulphides indicates that the " chain " sulphur atoms are smaller than those at the ends of the chains, which is to be expected since the latter should carry the greater part of the negative charge.218 Polysulphides of several amines have been obtained by reaction of hydrogen sulphide with solutions of the amine and sulphur in organic (preferably non-polar) solvents. Compounds prepared in this way include (Me,N),H,S, and (Et3N),H,Sg; both form orange-coloured crystals. 219 The reaction between sulphur trioxide and ammonia has been investig- This can happen at room temperature.214 208 I?. Fairbrother, W. C. Frith, and A. A. Woolf, J. , 1954, 1031. 2oB H. Schafer and L. Bayer, 2. anorg. Chem., 1954, 277, 140. 310 0. Ruff and F. Thomas, ibid., 1925, 148, 1 . 211 H. Schafer and L. Grau, ibid., 1954, 275, 198. 412 P. A. GiguZ?re and K. B. Harvey, J . Amer . Chem. Soc., 1964, 76, 6891. 213 D. L. Schechter and J. Kleinberg, ibid., p. 3297. 214 D. J. C. Bailey, Chem. a9ad I n d . , 1954, 492. 215 D. M. Gardner and G. K. Fraenkel, J . Amer. Chem. SOC., 1954, 76, 5891. 217 Idem, ibid., p. 144. 219 H. Krebs, E. F. Weber, and 11. Balters, ibid., p. 147. F . F6her and H. J. Berthold, 2. anorg. Chem., 1953, 274, 223. 2 1 s Idem, ibid., 1954, 275, 241. Pu bl is he d on 0 1 Ja nu ar y 19 54 . D ow nl oa de d by U ni ve rs ity o f C al if or ni a - R iv er si de o n 29 /1 0/ 20 14 1 7: 30 :3 3. View Article Online http://dx.doi.org/10.1039/ar9545100118 140 INORGANIC CHEMISTRY. ated several times and is not a t all simple. The previously supposed 220 intermediate formation of sulphamic acid, NH,*SO,H, and iminodisulphonic acid, NH(SO,H),, has been disproved. The reaction appears to consist of the formation of sulphimide, SO,:NH, which partly polymerises to ring compounds, and partly forms polymeric chains,221 H0,S-(-NH-SO,-),-OH. Trisulphuryl chloride, S,O,Cl,, has been isolated from the reaction be- tween sulphur trioxide and carbon tetrachloride. Pyrosulphuryl chloride, S,O,Cl,, which is well known, is also formed.222 The preparation of thionyl bromide, which now becomes a reagent of value for the substitution of bromine for hydroxy-groups in organic com- pounds,223 has been much improved. It is formed when thionyl chloride is added to a solution of potassium bromide in sulphur dioxide.224 A mixture of sulphur bromides, S,Br, (n varies from 4 to ll), has been obtained by the action of hydrogen on sulphur monobromide, S,Br, ; hydro- gen bromide is eliminated. Higher sulphur chlorides have also been prepared.225 A new oxysulphide of nitrogen, S,N,O,, has been prepared by the reaction between nitrogen sulphide and sulphur trioxide ; it is colourless, crystalline, easily sublimed, and soluble without reaction in nitrobenzene. The oxysulphide is very sensitive to moisture, and a study of the hydrolysis products has shown that two of the sulphur atoms are Pyridine vapour is absorbed, with formation of two moles of the betaine C,H,N*SO,-, which, together with the fact that the sulphur dioxide obtained by the hydrolysis of samples prepared from radioactive sulphur trioxide and normal nitrogen sulphide is inactive, suggests the constitution (111) .226 Addition of potassium amide to a liquid ammonia solution of sulphur nitride gives a yellow precipitate, K3N,S2, which takes fire in the air and is very reactive to water and alcohols. The reaction is thought to take the course N4S, + GKNH, = 2KNS + 2(KN),S + 4NH,. The substance is soluble in formamide, and the molecular weight in this solvent agrees with dissociation into 3K+, NS-, and N,S2- ions.227 The preparation of ammonium sulphimide, (NH4*NS02),, by the thermal rearrangement of sulphamide has been improved, and a variety of other salts obtained. The silver salt Ag3(NS02).,,3H,0 can be dehydrated and converted into the free acid by hydrogen chloride in dry ether. Sulphimide (HN*SO,), polymerises readily, and is rapidly hydrolysed. Dilute solutions, however, are relatively stable and can be titrated electro- or conducto-metrically ; the first two dissociation constants are fairly large, the third being much smaller, but sulphimide can be titrated as a tribasic acid with 0-IN-sodium hydroxide (phenolphthalein) .228 fs\\sT (111) Oas\ /SO2 in the +6 oxidation level, the other +a. 0 + s20 P. Baumgarten and A. H. Krummacher, Ber., 1934, 67, 1257. aal R. Appel and W. Huber, 2. anorg. Chem., 1954, 275, 338. 22a H. A. Lehmann and G. Ladwig, Chem. Tech., 1953, 5, 455. 223 M. J. Frazer, W. Gerrard, G. Machell, and B. D. Shepherd, Claem. and Ind., 1954, 2 2 6 F. FCher and G. Rempe, 2. Naturforsch., 1953, Sb, 688; F. FCher and J. Kraemer, 226 M. Goehring, H. Hohenschutz, and J. Ebert, 2. anorg. Chem., 1954, 276, 47. 2 2 7 W. Berg and M. Goehring, tbid., 1954, 275, 273. 228 G. Heinze and A. Meuwsen, ibid., p. 49. 931. ibid., p. 687. 224 M. J. Frazer and W. Gerrard, ibid., p. 280. Pu bl is he d on 0 1 Ja nu ar y 19 54 . D ow nl oa de d by U ni ve rs ity o f C al if or ni a - R iv er si de o n 29 /1 0/ 20 14 1 7: 30 :3 3. View Article Online http://dx.doi.org/10.1039/ar9545100118 COATES AND GLOCKLING. 141 Dithio-acids combine readily with many heavy metals giving coloured compounds, some of which are useful analytically. There is evidence that the four-membered rings considered to be present in these compounds open easily in the presence of electron donors : 229 PY is\ J. R.C\ 7M, ,C*R + 2 py e- R*CS.S*M-S*CS*R s s + PY Tetrapyridinecopper(11) tetrathionate is very much less soluble than the tri- or penta-thionate, and is suitable both for the separation of tetrathionate from other polythionates, and for the gravimetric analysis of copper. Tri- and penta-thionate ions can be precipitated as salts of the hexammino- cobalt(II1) ion.230 The yellow dioxide of polonium, PoO,, formed by decomposition of the nitrate or oxidation of the metal a t 300°, provides further evidence (by X-ray analysis) for the existence of quadrivalent Po4+ ions.231 Chromium and molybdenum cyclopentadienyls have been prepared by new methods. Tetrahydrofuran has been found an excellent reaction medium for the interaction of cyclopentadienylsodium with anhydrous metal chlorides, and the red, exceedingly air-sensitive chromium compound /C,H,),Cr, reported last year, has been obtained in 70% yield by this method. Compounds containing cyclopent adienyl-molybdenum and -tun@ en ions were similarly obtained.232 The other method involves the interaction of cyclopentadiene itself with the hexacarbonyls of these elements a t 280- 340". Chromium hexacarbonyl [as well as Fe(CO),, Co,(CO),, and Ni(CO),] afforded normal biscyclopentadienyl derivatives of the metals, but the hexa- carbonyls of molybdenum and tungsten under similar conditions gave the remarkable mixed cyclopentadienyl-carbonyls C,H,Mo(CO) ,MoC,H, and C,H,W(CO)6WC,H,. Both are quite stable and have molecular weights corresponding to the formulze given above, and they are diamagnetic. The structures of these compounds are formulated as three-tiered sandwiches, each metal atom being bonded to a cyclopentadienyl ring, with carbonyl groups bridging the atoms. Preliminary X-ray data are consistent with this interpretation .% In its reactions with transition metals the isocyanide molecule RNC is remarkably similar to carbon monoxide, and a series of hexaisocyanide deriv- atives of chromium,234 molybdenum,235 and tungsten 236 has been obtained, eg . , Cr(CN*C,H5) 6 from chromous acetate and W(CN*C,H,) g from tungsten hexachloride and phenyl isocyanide. These are closely analogous to the carbonyls M (CO) 6. Many oxides of chromium of compositions between Cr203 and CrO, have been described at various times, but there has been much doubt about the identity of many of them. The slow decomposition of both chromium(v1) 229 H. Krebs, E. F. Weber, and H. Fassbender, 2. anorg. Chem., 1954, 276, 128. 230 G. Heinze, ibid., p. 146. 232 F. A. Cotton and G. Wilkinson, 2. Naturforsch., 1954, 9b, 417. 233 G. Wilkinson, J . Amer. Chem. SOC., 1954, 76, 209. z34 L. Malatesta, A. Sacco, and S. Ghielmi, Gazzetta, 1952, 82, 516. 235 L. Malatesta, A. Sacco, and M. Gabaglio, ibid., p. 548. 2a6 L. Malatesta and A. Sacco, A?m. Chim. (Italy), 1953, 43, 622. asl A. W. Martin, J . Phys. Chem., 1954, 58, 911. Pu bl is he d on 0 1 Ja nu ar y 19 54 . D ow nl oa de d by U ni ve rs ity o f C al if or ni a - R iv er si de o n 29 /1 0/ 20 14 1 7: 30 :3 3. View Article Online http://dx.doi.org/10.1039/ar9545100118 142 INORGANTC CHEMISTRY. trioxide and chromyl chloride in a stream of oxygen has been followed by X-ray analyses and magnetic measurements. The first oxide formed is Cr02.6(Cr5013) which is followed by an oxide of continuously variable com- position Cr02.38-2.48. The ferromagnetic dioxide CrO, is formed in small amounts and is best obtained from chromyl chloride; it has a rutile-type structure, the radius of the W+ ion being 0.55 A. Similar oxides are formed by the cautious thermal decomposition of ammonium dichromate, but the dioxide is not produced in this reaction. Chromium dioxide has also been prepared by the decomposition of the trioxide at 420-450" under an oxygen pressure of 200-300 atm.237 Spectrophotometric examination of the de- composition of blue " perchromic acid " has shown that chromium(II1) dichromate appears to be the main product, rather than chromium(v1) tri- oxide or chromium(r1r) chromate as had earlier been supposed.238 The exchange between the green chromium(1n) chloride and chloride ions, examined by means of radioactive chlorine, is extremely slow, so the complex [CrC1,(H20)4]+ is essentially covalently bound.239 Solutions of molybdenum(v) change colour from green to brown as the acidity changes from 8 to 2~ (HCl).240 Magnetic evidence shows that at hydrochloric acid concentrations greater than 7 ~ , molybdenum(v) ions exist as monomers (one unpaired electron). A t lower concentrations of hydro- chloric acid the magnetic susceptibility falls as electron pairing takes place, and below 26~-hydrochloric acid all the molybdenum(v) ions are present as dimers linked by an electron-pair bond, Mo(v)-Mo(v) .241y 242 A number of fluoromolybdates have been prepared by the action of aqueous potassium fluoride on molybdenum(vr) trioxide. These include K,MoO,F,, K2Mo0,F,,H,0, K3Mo,O,,F,3H2O, and K,Mo02F4,H20 ; the fluorotungstate K2W0,F2,H20 was also obtained.243 More data on tungsten bronzes (Na,WO,) have been reported.2M Uranium and the Transuranic Elements.-Published work on the in- organic chemistry of uranium has mainly concerned its complexes in aqueous solution or in mixtures of water with organic solvents. Visible and ultra- violet spectra of uranyl complexes with p-diketones in anhydrous and aqueous organic solvents provide evidence for the existence of strong covalent bonds between the metal and the ligands. The high degree of hydration and solvation supports the view that the U(VI) atom in such complexes has a co-ordination number greater than ~ i x . ~ 5 The conduc- tivity of the uranyl nitrate complex with benzoylpicolinoylmethane suggests the presence of covalent U-N bonds.246 Uranyl nitrate combines with citric, malic, and tartaric acids a t pH 3.5 to form binuclear complexes by tridentate chelation involving oxygen or hydroxy-bridges between uranium atoms. In slightly alkaline solution similar trinuclear complexes are formed.=' Data 237 0. Glemser, U. Hauschild, and F. Triipel, 2. anorg. Chem., 1954, 277, 113; S. M. Ariya, S. A. Shchukarev, and V. B. Glushkova, J . Gen. Chem. (U.S .S .R . ) , 1953, 23, 1107 (U.S. trans.). 239 H. van der Straaten and A. H. W. Aten, Rec. Trav. chim., 1954, 73, 157. 240 I. M. Issa and H. Khalifa, J. Indian Chem. SOC., 1964, 31, 91. 2 4 1 M. M. Jones, J. Amer. Chem. SOC., 1954, 76, 4233. 242 L. Sacconi and R. Cini, ibid., p. 4239. 243 0. Schmitz-Dumont and P. Opgenhoff, Z . anorg. Chem., 1954, 275, 21. 944 B. W. Brown and E. Banks, J . Amer. Chem. SOC., 1954, 76, 963. 2 4 5 L. Sacconi and G. Giannoni, J., 1954, 2751. 2 4 7 I Feldman, J . R. Havill, and W. F. Neumann, J . Asner. Chem. SOC., 1954, '96,4726. 238 R. C. Rai and S. Prakash, 2. anorg. Chem., 1954, 275, 94. 246 Idem, ibid., p. 2368. Pu bl is he d on 0 1 Ja nu ar y 19 54 . D ow nl oa de d by U ni ve rs ity o f C al if or ni a - R iv er si de o n 29 /1 0/ 20 14 1 7: 30 :3 3. View Article Online http://dx.doi.org/10.1039/ar9545100118 on the stability of uranyl complexes with 2-thenoyltrifluoroacetone have been obtained and related to the use of that complexing agent for the solvent extraction of uranium.24s Uranium selenide and the tellurides, Use, UTe (both with the NaCl structure), U,Te4, and UTe,, have been prepared by heating the elements together, and their structures have been determined. The oxyselenide UOSe results when potassium cyanide, selenium, and uranium oxide are melted together : 249 SKCN + U,O, + 3Se = 3UOSe + FiKCNO Three solid phases have been identified from solubility studies on uran- ium(v1) orthophosphate in phosphoric acid. These are (UO2),(P0,),,6H,O, U0,HP04,4H,0, and U0,(H,P0,),,3H,0.250 Five allotropes of plutonium are reported having densities between 16.4 and 19. The negative temperature coefficient of expansion of &plutonium is of interest as possibly being unique for a polycrystalline pure The hydrates of uranium and plutonium tetrafluorides have been re- investigated : both form salts MF4,2-5H,O, and a lower hydrate with 2H20 or less.,S2 Plutonium dioxide or oxalate and anhydrous hydrogen fluoride give the tetrafluoride (PuF,) in the presence of oxygen and the trifluoride in its absence. The tetrafluoride is readily reduced to the trifluoride by hydro- gen. The hydrate PuF4,26H,O decomposes to the trifluoride when heated.253 The direct fluorination at 500' of americium-(Irr), -(Iv), and -(v) compounds has led to the isolation of AmF, and KAmF,.254 Evidence that actinides form complex ions with chloride to a greater extent than the lanthanides has been obtained from cation-exchange studies at high hydrochloric acid concentration. The actinide complex ions are considered as partly covalent, with hybridisation involving the 5f orbitals.255 Group VI1.-The heat of atomisation of fluorine, which has been in dispute, has been measured by an effusion method; AH0298 = 37.6 & 0.8 kcal. /mole.256 The possible ability of fluorine to exert a covalency of two is of consider- able interest. A compound H2F*CI04, m. p. 56-58', prepared from an- hydrous hydrogen fluoride and anhydrous perchloric acid was described in 1930.257 Recent experiments, however, conducted with carefully dried materials indicate that this compound does not Fluorine converts dry sodium nitrite almost quantitatively into nitryl fluoride, N0,F : 2NaN0, + F, + 2NaF + 2N0, Nitryl fluoride reacts with most metals below 300" to yield either the fluoride ZNO, + F, -ID- 2N0,F 2 4 8 R. A. Day and R. M. Powers, J . Amer. Chem. SOC., 1954, 76, 3895. 21y R. Ferro, 2. anorg. Chem., 1954, 275, 320. 260 J . M. Schreyer and C. F. Baes, J . Awser. Chem. SOL-., 1954, 76, 354. z61 W. B. H. Lord, ,Valure, 1954, 173, 534. Z 5 2 J. K. Dawson, R. W. M. D'Eye, and A. E. Truswell, J., 1954, 3922. 2 5 3 J. K. Dawson, R. M. Elliott, R. Hurst, and A. E. Truswell, J . , 1954, 555. z 5 4 L. 13. Asprey, J . ,4mer. Chem. SOC., 1954, 76, 2019. 2 5 5 M. Diamond, K. Street, and G. T. Seaborg, ibid., p. 1461. 2 j s €1. Wise, J . Phys. Chem., 1954, 58, 389. 2 5 8 G. Rrauer and €I. Distler, 2. atlorg. Chem., 1954. 275. 157 z 6 7 A. Hantzsch, Ber. , 1930, 63, 1789. Pu bl is he d on 0 1 Ja nu ar y 19 54 . D ow nl oa de d by U ni ve rs ity o f C al if or ni a - R iv er si de o n 29 /1 0/ 20 14 1 7: 30 :3 3. View Article Online http://dx.doi.org/10.1039/ar9545100118 144 TNORGANIC CHEMISTRY. and oxide or the oxyfluoride. Non-metals, with the exception of bromine and tellurium, form nitronium salts : e.g., (N0,)SeF,.259 A number of fluorosulphonyl complexes have been formed by reactions between metal halides and fluorosulphonic acid in the complete absence of water. Those characterised include TiCl,(SO,F),, ZrF,(SO,F), TaCI,(SO,F),, and SF,(S0,F).260 Oxidative hydrolysis of di-iodo( trifluoromethy1)arsine with aqueous hydrogen peroxide readily yields trifluoromethylarsonic acid, which under- goes progressive dehydration in uucuo forming first a pyro-acid and then an anhydride : 3 5'1 1 0-* 73'1 lo-* m. mm . CF,*AsI, _t CF,*ASO(OH)~ + (CF,*AsO*OH*),O + CF,*AsO, Both trifluoromethylarsonic acid and the previously described bistrifluoro- methylarsinic acid, (CF,),AsO(OH), are almost completely ionised in aqueous solution and are therefore much stronger acids than methylarsonic and cacodylic. Interesting use is made of infrared spectra for characterisation purposes.261 Trifluoromethyl-phosphonous and -phosphonic acids, CF,*P(OH), and CF,*PO(OH),, have also been prepared and studied. Like the corresponding arsenic compounds they are remarkably strong acids. The phosphonous acid was obtained by hydrolysis of the halides CF,*PX, or (CF,),PX (X = C1 or I) or by controlled hydrolysis of (CF,),P, and the phosphonic acid by oxidative hydrolysis ( H202-H,O) of these three compounds. Oxidation of the phosphonous acid yields trifluoromethylphosphonic acid. Trifluoro- methylphosphonous acid is monobasic and the structure, CF,*PH(:O)*OH, is also indicated by its infrared spectrum; i.e., i t is really trifluoromethyl- phosphinic acid. In contrast to CF,*P(O)(OH), the phosphonous acid is volatile in water vapour at reduced pressure. Bistrifluoromethylphos- phinous acid, (CF,),P*OH was also prepared. I t is unstable in water, yielding fluoroform and CF3*PH(0)*OH.262 Compounds containing fluoro- carbon radicals were reviewed in the Liversidge Lecture.a6a Reactions of fluorine with various metals and their oxides are reported. Titanium, zirconium, tin, and their oxides react at moderately low tem- peratures forming the tetrafluorides. Vanadium(v) oxide, V205, yields the oxyfluoride VOF, at 475". Copper and a number of its compounds form cupric Aredcrystallineoxy-sulphateof chlorine, dichloryl trisulphate (ClO,),S,O,,, has been prepared from potassium chlorate (or chlorite) and sulphur trioxide. It is perceptibly volatile in a vacuum and is formulated as a salt of the chloryl ion C102+ .265 Chloryl fluoride C10,F has been further studied.266 2 5 Q E. E. Aynsley, G. Hetherington, and P. L. Robinson, J. , 1954, 1119. 260 E. Hayek, J . Puschmann, and A. Czaloun, Monatsh., 1954, 85, 359. *61 H. J . Emelhs , R. N. Haszeldine, and R. C. Paul, J . , 1954, 881. 262 F. W. Bennett, H. J . Emelkus, and R. N. Haszeldine, ibid., p. 3598. 263 H. J. EmelCus, ibid., p. 2979. 264 H. M. Haendler, S. F. Bartram, R. S. Becker, W. J. Bernard, and S. W. Bukata, J . Amer. Chew. SOG., 1954, 76, 2177; H. M. Haendler, L. H. Towle, E. F. Bennett, and W. L. Patterson, ibid. , p. 2178; H. M. Haendler, S. F. Bartram, IV. J . Bernard, and D. Kippax, ibid., p. 2179. 2 6 5 H. A. Lehmann and G. Kriiger, 2. anorg. Chent., 1953, 274, 141; see also A . .4. Woolf, Chewz. and Ind., 1954, 346. 266 M. Schmeisser and F. L. Ebenhoch, Angew. Chem., 1954, 66, 230. Pu bl is he d on 0 1 Ja nu ar y 19 54 . D ow nl oa de d by U ni ve rs ity o f C al if or ni a - R iv er si de o n 29 /1 0/ 20 14 1 7: 30 :3 3. View Article Online http://dx.doi.org/10.1039/ar9545100118 COATES AND GLOCKLTNG. 145 Several physical properties of iodine pentafluoride have been measured 267 including the dielectric constant 268 which is surprisingly high (41.1 a t 0"). Experimental procedures are given for the preparation of metallic chlorides [Co, Ni, Mn, Zn, and C~(III)] by chlorination of the metal in the presence of a donor solvent such as ethanol or ether.269 The bright yellow substance formed when 100% nitric acid acts on iodine is iodyl nitrate, IONO,, not neutral iodine nitrate I(NOJ,, as often Phase studies on the ternary system BaBr,-WgBr,-H,O at 25", 10*4", and 4.5" are reported. At the lower two temperatures a solid phase con- taining all three components is present.271 Manganese carbonyl, Mn,(CO),,, has been obtained from manganese iodide, magnesium, and carbon monoxide in ether under high pressure. It forms volatile golden-yellow crystals (m. p. 155" in sealed tube) which are soluble in organic solvents. With iodine it forms Mn(CO),I as ruby-red crystals, m. p. 115". X-Ray and infrared data were obtained for Mn,(CO),,. The absence of an absorption band in the 5.5 p region (see ref. 287) suggests that manganese carbonyl, like Re,(CO),, but unlike Fez( CO),, dimerises through the formation of metal-metal bonds rather than bridging carbonyl groups .272 From the reaction between manganese chloride and cyclopentadienyl- magnesium bromide both biscyclopentadienyl-manganese and -magnesium can be separately isolated. Biscyclopentadienylmanganese forms a mixed cyclopen tadien yl-carbonyl, C,H,-Mn( CO),, m. p. 77 ", with carbon monoxide under pressure, which is monomeric in benzene solution. At normal temperatures it is diamagnetic, but is remarkable in that it becomes para- magnetic a t low temperatures.273 Biscyclopentadienylmanganese, from cyclopentadienylsodium and man- ganese(r1) bromide in tetrahydrofuran, presents an interesting case of isomer- ism since the brown paramagnetic form (three unpaired electrons) stable a t room temperature becomes white sharply a t 158-159", and then melts a t the characteristic temperature 172-173". The white form, which has only one unpaired electron, reverts to the brown form on slow cooling, but the process can be halted by sudden cooling. It has been suggested that the bonding in the brown form, which is highly reactive, is similar to that which obtains in, for example, an alkyl derivative of an electropositive metal, the white form on the other hand having the typical biscyclopentadienyl structure.274 Salts of the univalent ion containing manganese(I), e.g., [Mn(CNR),]+I-, have been obtained by reaction of aromatic isocyanides with manganese(I1) iodide. Treatment with iodine does not oxidise the stable (diamagnetic) hexaisocyanidemanganese(1) ion, but gives the periodide [Mn(CNR)6]+13-.275 267 M. T. Rogers, J. L. Speirs, H. B. Thompson, and M. B. Panish, J . Amer. Chem. SOL., 1954, 76, 4843. 2 6 8 31. T. Kogers, H. B. Thompson, and J. L. Speirs, ibid., p. 4841. 203 R. C. Osthoff and R. C. West, ibid., p. 4732. 2 7 0 T. Kikindai, Compt. rend., 1954, 288, 1229. 2 7 1 H. J. V. Tyrrell and J. Richards, J . , 1953, 3812. 2 7 2 E. 0. Brimm, M. A. Lynch, and W. J. Sesny, J . Amer. Chewz. SOC., 1954,76, 3831. 273 E. 0. Fischer and R. Jim, 2. Naturforsch., 1954, 9b, 618. 2 7 4 G. Wilkinson and F. Cotton, Chem. and Ind. , 1954, 307. 2 7 5 A. Sacco, Atti Accad. naz. Lincei, Rend. Classe Sci . f is . mat. nat., 1953, 15, 421. . stated.270 Pu bl is he d on 0 1 Ja nu ar y 19 54 . D ow nl oa de d by U ni ve rs ity o f C al if or ni a - R iv er si de o n 29 /1 0/ 20 14 1 7: 30 :3 3. View Article Online http://dx.doi.org/10.1039/ar9545100118 146 INORGANTC CHEMISTRY. Potassium manganate is not readily obtained in a pure state, but has recently been purified to 9943%. Its thermal decomposition is complex, but proceeds mainly by the reaction 3K,Mn04 = 2K3Mn0, .+ MnO, + 0,. A certain amount of K2Mn0, is also formed together with oxides of variable The highly reactive fluorides of permanganic and per-rhenic acids, MnO,F and ReO,F, have now been isolated in a pure state and characterised. The former was obtained from potassium permanganate and hydrogen fluoride or fluorosulphonic acid : KMnO, + 2HF = Mn0,F + K F + H,O KMnO, + 2F*SO,H = Mn0,F + KS03F + H,SO, It forms dark green crystals, m. p. -38", b. p. (extrap.) -60"; the vapour is an intense green. The rhenium oxyfluoride, ReO,F, was prepared from the corresponding chloride and anhydrous hydrogen fluoride. It formed a yellow solid melting (at 147') to a very viscous Reduction of potassium per-rhenate, KReO,, with potassium in aqueous ethylenediamine leads to the isolation of potassium rhenide KRe in an impure state as a grey hydrated solid. Its paramagnetism was less than is required for an atom with one unpaired electron. Since rhenium contains five un- paired electrons this magnetic evidence suggests that the Re- ion exists as a hydrated complex having four water molecules co-ordinated at the corners of a ~quare.~78 Rhenium and germanium are shown by X-ray and vapour- pressure measurements to form only the highly inert compound, ReGe, (AH = -2 & 10 kcal.).,,, Group VII1.-The extensive work reported last year on cyclopent adienyl- metal complexes is now being extended to indene, which forms metal com- plexes, a t least with iron and cobalt, which are analogous to the cyclopenta- dienyl complexes. Bisindenyliron( 11) , Fe(C,H,),, has been prepared from ferric chloride and indenyl-lithium or indenylmagnesium bromide as a deep purple diamagnetic solid soluble in organic solvents. It sublimes in a vacuum at go", sinters in nitrogen at 160", and melts a t 179-181". Unlike biscyclopentadienyliron, Fe(C5H,),, it is not oxidised to the corresponding water-soluble cation, Fe(C,H,),+, because of decomposition.280 Catalytic reduction 281 gives bistetrahydroindenyliron, Fe(C,H,,),, as a diamagnetic oil, m. p. 18.5-19", which can be distilled in V ~ C U O at 125". Bisindenyl- cobalt, Co(C,H7),, has been prepared from indenyl potassium and CO(NH,)~(SCN), in liquid ammonia solution. The initially formed complex, [CO(NH,)~][C,H,], loses all its ammonia in a vacuum. Bisindenylcobalt forms black paramagnetic crystals, and is monomeric in benzene solution. It sublimes in a high vacuum at 100" and sinters about 160". Oxidation with hydrogen peroxide or potassium persulphate gives the corresponding composition, M1101.75-1.8~. 276 Above 0" it decomposes explosively. 2 7 6 R. Scholder and H. Waterstradt, 2. anorg. Chem., 1964, 277, 172. 2 7 7 A. Engelbrecht and A. V. Grosse, J . Amer. Chem. SOC., 1954, 76, 2043. 2 7 8 J . B. Bravo, E. Griswold, and J. Kleinberg, J . Phys. Chem., 1954, 58, 18. 27e A. W. Searcy, R. A , McNees, and J. M. Criscione, J . Amer. Chem. SOC., 1954, 76, 280 E. 0. Fischer, D. Seus, and R. Jira, 2. Natwforsch., 1953, 8b, 693, 694: 1'. I.. 5287. Pauson and G. Wilkinson, J . Amer. Chem. SOG., 1954, 76, 2024. E. 0. Fischer and D. Sew, 2. A'aturforsch., 1954, 9b, 386. Pu bl is he d on 0 1 Ja nu ar y 19 54 . D ow nl oa de d by U ni ve rs ity o f C al if or ni a - R iv er si de o n 29 /1 0/ 20 14 1 7: 30 :3 3. View Article Online http://dx.doi.org/10.1039/ar9545100118 COATES AND GLOCKLTNG. 117 cation [Co(C,K,) 2]+, which also results from treatment of indenylmagnesium bromide with cobalt(1r)-acetylacetone. Bisindenylnickel has been mentioned as a deep red-brown solid.280 Further reports have appeared on biscyclopentadienyl compounds of iron, cobalt, and nickel. They are obtained in poor yields from the metal carbonyls and cyclopentadiene. The heat of formation of Ni(C,H,), from the elements is 62.8 & 0.5 kcal./mole [compare AH” for Fe(C5H5)2, 33.8 kcal. /mole]. Magnetic-susceptibility measurements on Ni(C5H5)2 and [Ni(C,H,),]+ show the presence of two and one unpaired electrons, respec- tively.282 Ferrocene and n-butyl-lithium form a mixture of mono- and di- metallated products, indicating that the hydrogen atoms are more acidic than in benzene.283 Small yields of ferrocene and of (C5H5)2TiC12 have been obtained by the interaction of cyclopentadiene and the metal chloride in the presence of a hydrogen halide acceptor such as an amine : 284 2C,H, + FeC1, + 2Base - Fe(C,H,), + 2Base, HC1 Phase-diagram studies on the system Fe2O3-P,O5-H2O have revealed the four stable solid phases : Fe20,,P20,,5H20 ; Fe20,,2P205,8H20 ; Fe203,3P20,,10H20 ; Fe203,3P20,,6H20, the last probably being H3[Fe(HP0,),]. Diferric tetraphosphate was found as a metastable solid phase.285 Equimolar mixtures of citric acid and ferrous or ferric perchlorate 0 0 Ill Ill 111 111 0 0 Reproduced, by permission, from J. W. Cable, R. S. Nyholm, and R. K. Sheline, J . Amer. Chern. Sor., 1954, 76, 3373. (IV) form a variety of complexes depending on the pH of the solution, and formation constants have been calculated. The species identified from ferrous are FeHCit, (FeCit)-, and (FeOHCit)2-, and from ferric, (FeHCit)+, FeCit, (Fe0HCit)-, and [ Fe (OH) ,CitI2- .286 Further important advances have been made in the chemistry of carbonyl com- pounds, A spectral examination of dicobalt octacarbonyl has revealed absorption in the 5.5-p region of the spectrum, strongly indicating the presence of bridged carbonyl groups in the molecule, in addition to carbon monoxide-type carbonyl groups. Of various possible structures a trigonal bipyramidal configuration (IV) about each cobalt atom is favoured. The bridged carbonyls are considered to be similar to those in strained cyclic ketones.287 With acetylene and a number of substituted acetylenes, dicobalt octa- carbonyl undergoes a remarkable reaction, quantitative at room temperature, whereby the two bridge carbonyl groups are replaced by one molecule of the acetylene : R-CiC-R’ + CO~(CO), _t C~RR’CO~(CO), -1 2CO a82 G. Wilkinson, P. L. Pauson, and F. A. Cotton, J , Amer. Chem. SOC., 1954, 76,1970. 283 R. A. Benkeser, D. Goggin, and G. Schroll, ibid., p. 4025. 2 8 5 R. F. Jameson and J. E. Salmon, r., 1954, 28. 288 R. E. Hamm, C. M. Shull, and D. M. Grant, J . Amer. Chem. Soc., 1954, 76, 2111. 2 8 7 J. W. Cable, R. S. Nyholm, and R. I 148 INORGANIC CHEMISTRY. The diphenylacetylene compound (R = R' = Ph) formed deep purple crystals, m. p. 110", which sublimed at 90" under 1 mm. pressure. It is diamagnetic and monomeric in cyclohexane, and its dipole moment is re- ported as 2.1 D. Examination of the infrared spectrum of this and related compounds showed bands corresponding to the terminal carbonyl groups in dicobalt octacarbonyl. The characteristic bridge carbonyl frequency was absent, as also were bands corresponding to acetylene groups. Certain of the derivatives such as that from ethylene itself showed a band a t 3096 cm.-l, characteristic of an ethylenic or aromatic C-H bond. This evidence leads to two types of possible structure (V and VI). In (VI), which cannot be 0 R 0 \\ I 2 o=c=co:;- j -;;g=c=o HC \c R c\\ ,c.. 0=c=co=c \ I R0 \o // \ RC 1 , Nc c=co=c=o // 'F' ".., R' 0 flC 0 (V) (VI) represented by localised bonds, the C-C and Co-Co bonds may be coplanar or perpendicular.28 Further investigations on the reactions of cobalt carbonyls with a variety of bases have shown that the tricarbonyl [Co(CO),], is quantitatively trans- formed into a [Co(CO),] derivative : ~[CO(CO),], + 24C5H5N = ~[CO(C,H,N),][CO(CO),], + 4CO Dicobalt octacarbonyl not only reacts with pyridine and amines in the manner reported last year, but also with such weak bases as acetone : ~[CO(CO)~], + 12COMe, = ~[CO(COM~,),][CO(CO)~]~ + 8CO The ions [Co(COMe2),l2+, [CO(M~-CN),]~+, and [c~(hfe*NH,),]~+ have been obtained in this way. The reaction with methylamine is of particular interest : 289 ~[CO(CO),]~ + 20Me*NH2 = ~[CO(M~=NH,) , ] [CO(C~)~] , + 8Me*CO*NH, A solution of cobalt (11) chloride in aqueous potassium cyanide absorbs carbon monoxide in the presence of much hydroxide ion, the cobalt being reduced by part of the carbon monoxide with formation of carbonate and the [Co(CN),C0I2- ion containing cobalt(1). The only solid salt of this ion was formed with tris-o-phenanthroline-iron(xr), [Fe phenan,][Co(CN),CO], as a bright red precipitate.2w Compounds of cobalt(0) have been prepared by the reduction of K,Co(CN), suspended in liquid ammonia containing potassium, K,Co(CN) 6 + 3K = K4Co(CN), + 2KCN. The potassium tetracyanocobalt(0) is obtained as a brown-violet hygroscopic powder, very sensitive to air (in which it is pyrophoric) and moisture. It immediately liberates hydrogen on addition to water. The ion CO(CN),~- would contain an odd number of electrons, 2 8 8 R. A. Friedel, H. Greenfield, R. Markby, H. W. Sternberg, I. Wender, and J. Wotiz, J . Amer. Chem. SOC., 1954. 76, 1457. 290 W. Hieber and C. Bartenstein, 2. anorg. Chem., 1954, 276, 1 . W. Hieber and J. Sedlmeier, Chern. Ber., 1954, 87, 25, 789. Pu bl is he d on 0 1 Ja nu ar y 19 54 . D ow nl oa de d by U ni ve rs ity o f C al if or ni a - R iv er si de o n 29 /1 0/ 20 14 1 7: 30 :3 3. View Article Online http://dx.doi.org/10.1039/ar9545100118 COATES AND GLOCKLING. 149 but the weak paramagnetism (043 B.M.) of the potassium salt, which is difficult to keep pure, indicates a dimeric structure analogous to that of dicobalt octacarbonyl, viz., K,[Co,(CN),]. This compound, when suspended in ammonia, absorbs carbon monoxide : K,[Co,(CN),] + CO = K,[Co,(CN),CO] + KCN Dicobalt octacarbonyl similarly reacts with potassium cyanide with partial displacement of carbon monoxide and formation of a mixture of K,[Co,(CN),(CO),] and K,[CO,(CN),(CO)~]. Of particular interest is the reaction between sodium tetracarbonyl cobalt and sodium cyanide in liquid ammonia, which results in the partial formation of sodium tricarbonyl cyanocobalt(-I) : NaCo(CO), + NaCN = N~,[COCN(CO),].~~~ There have been considerable advances in the chemistry of the isocyanide derivatives of the transition elements (see also Cr, Mo, W, and Mn). Addi- tion of $-tolyl isocyanide to an alcoholic solution of ferrous chloride gives two isomeric compounds, Fe(CNR),Cl,, one deep blue-violet, the other brown ; both are diamagnetic.292 These compounds are evidently octahedrally co- ordinated and non-electrolytes. Pentaisocyanide derivatives of cobalt (I), [Co(CNR),]+X-, were reported last year. Several derivatives of cobalt(11) have now been described; addition of an aromatic isocyanide to cobalt(I1) iodide affords two isomeric compounds Co(CNR),12, one metastable, green or blue, and diamagnetic, the other stable, reddish , and paramagnetic. With silver perchlorate a 1 : 1 electrolyte is formed, [Co(CNR),I]C104, in a disproportionation reaction. In this compound the unusual five co-ordin- ation of the CO(I) complexes disappears but is present again in [Co(CNR),] (ClO,),, obtained from the isocyanide and cobalt(@ perchlorate. The pentaisocyanidecobalt (11) complexes are paramagnetic to an extent corresponding to the presence of one unpaired electr0n.~~3 Mixed isocyanide-carbonyls of cobalt have been described, and are cobalt carbonyl salts of the pentaisocyanidecobalt (I) cation, e.g. ,,* CO,(CO)~ + SRNC = [CO(CNR),][CO(CO)~] + 4CO NaCo(CO), + [Co(CNR),]ClO, = [Co(CNR),][Co(CO),] + NaC10, by several methods, viz., (1) the displacement of carbonyl by isocyanide, Fe(NO),(CO), + 2RNC = Fe(NO),(RNC), + 2CO (2) reaction between isocyanides and other nitroso-compounds (q., Roussin’s salt), K,Fez(NO)4S, + 4RNC = 2Fe(N0)2(RNC), + K,S, [CO(NO)(NH~)~]C~~ + SRNC + *N2H4 = Co(NO)(RNC), + 2NH4C1 (3) the reaction between isocyanide complexes and hydroxylamine in alkaline solution, isocyanide-nitrosyl derivatives of both iron and cobalt have been obtained (black form) + 2NH, + p 2 Co(CNR),X + 2NH2*OH = Co(CNR),NO + 2RNC + H,O + NH4X 2s1 W. Hieber and C. Bartenstein, 2. araorg. Chem., 1954, 276, 12. 2s2 L. Malatesta, A. Sacco, and G. Padoa, Ann. China. ( I ta ly ) , 1953, 43, 617. ag4 A. Sacco, ibid., 1953, 83, 632. L. Malatesta and A. Sacco, Gazzetta, 1953, 83, 499; L. Malatesta, ibid., p. 958; A. Sacco, ibid., 1954, 84, 370. Pu bl is he d on 0 1 Ja nu ar y 19 54 . D ow nl oa de d by U ni ve rs ity o f C al if or ni a - R iv er si de o n 29 /1 0/ 20 14 1 7: 30 :3 3. View Article Online http://dx.doi.org/10.1039/ar9545100118 1 ti0 INORGANIC CHEMISTRY. The last reaction may well involve the disproportionation of hydroxylamine, 2NH2-OH = NH, + NOH + H,O. Many of the isocyanide-nitrosyls are quite stable compounds ; they are diamagnetic, monomeric, and soluble in organic solvents. The dipole moments of several derivatives containing fiara-substituted phenyl isocyanides have been measured ; the positive end of the dipole is in the direction of the phenyl isocyanide Nickel carbonyl and sodium in liquid ammonia give the dimeric carbonyl hydride [NiH(CO),],. The reaction involves also the formation of sodium carbonyl : BNi(CO), + 3Na -1- ZNH, = [NiH(CO),], -$- CO + NaCO -1- 2Na-NH2 Sodium carbonyl and sodamide separate from the reaction mixture, leaving the carbonyl hydride in solution. The hydrogen atoms in nickel carbonyl hydride appear to be non-a~id ic . ,~~ The reaction between nickel carbonyl and phosphorus trihalides giving complexes of nickel(O), Ni(PX,),, has now been extended to phosphorus tri- isocyanate and triisothiocyanate (X = NCO and NCS). The crystalline products are quite stable and A variety of nickel carbonyls in which one to four carbonyl groups have been replaced by phosphorus(rr1) has been described. These include such compounds as [ ($-MeO*C6H,*O),P],NiC0, [ (fi-N0,*C,H4*O),P],NiC0, and Ni(C,H,*PC&),, which are all prepared from the appropriate phosphorus(II1) compounds and nickel c a r b ~ n y l . ~ ~ ~ Attempts have been made to separate racemates by chromatographic adsorption. Several octahedral cobalt (111) complexes have now been separated on columns of ordinary potato starch. The separation is facilitated if the complexes contain hydroxyl or other groups which can associate with the hydroxyl groups of starch. Complexes such as cobalt(m) tris(amino- acetate) and trisethylenediaminecobalt (111) chloride were separated into optical isomers, as well as several ~anthates. ,~g Trisethylenediamine- cobalt (111) salts are racemised in the presence of decolorising The compound previously believed to be N~,[CO(NO,)~NO],ZH,O, is now considered to be N~,[CO(NO,),,NO,H,O].~~~ A potentiometric investigation of the reduction of potassium nickel@) cyanide by potassium in liquid ammonia shows that, with excess of salt pre- sent, two single-electron reactions occur : [Ni(CN)J2- -++ [Ni(CN),I3- [Ni(CN),I4-, whereas in the presence of excess of potassium a two-electron reaction occurs.3o2 Some quadridentate cobalt(I1) complexes and the 1 : 10-phenanthroline complex undergo isotopic exchange with labelled cobalt (11) ions, indicating ionic or weakly covalent bonding. I n contrast bistripyridylcobalt (11) shows Zg5 L. Malatesta and A. Sacco, 2. anorg. Chem., 1953, 274, 341. z96 H. Behrens and F. Lohofer, 2. Naturforsch., 1953, 8b, 691. 2g7 G. Willrinson, ibid., 1954, 9b, 446. 298 L. Malatesta and A. Sacco, Ann. Chim. (Italy), 1954, 44, 134. z9* H. Krcbs and R. Rasche, Z. anorg. Chem., 1954, 270, 236. 300 €3. E. Douglas, J . Amer. Chem. SOC., 1954, 70, 1020. 301 R. Nast and M. Rohmer, 2. anorg. Chem., 1954, 275, 162; see also J. 12. Frazer 302 G. W. Watt, J , L. Hall, G. R. Choppin, and P. S. Gentile, J . Amer. Chent. SOC., and N. 0. Long, J . Chem. Phys., 1938, 6, 462. 1954, 76, 373. Pu bl is he d on 0 1 Ja nu ar y 19 54 . D ow nl oa de d by U ni ve rs ity o f C al if or ni a - R iv er si de o n 29 /1 0/ 20 14 1 7: 30 :3 3. View Article Online http://dx.doi.org/10.1039/ar9545100118 WATES AND GLOCKLlNG. 151 a very slow rate of exchange.303 Cobalt inner complexes with salicylidene- anilines are suggested to possess a tetrahedral structure in contrast to the established planar configuration of the copper c o m p l e ~ e s . ~ ~ Sexadentate chelate compounds between cobalt (111) and various complex Schiff's bases such as the salicylidene derivative of (VII) have been investigated.3o5 If oxygen is bubbled through sodium or lithium hydroxide contained in nickel tubes a t 800°, the alkali-metal nickelates result, MNi0,.306 N=F-Ph --I- / -N, 2- / O Nickel forms red-to-brown diamagnetic complexes with acylhydrazones of a number of diketones and related compounds, some of which are mono- nuclear (e.g., VIII), and others polymeric, polynuclear complexes.307 A preliminary communication has appeared on certain bis-salicylaldimine complexes of nickel which are apparently solvated in pyridine, alcohol, or dioxan, and acquire an octahedral structure. The same complexes in chloroform, benzene, toluene, or xylene give interesting equilibria between planar diamagnetic and tetrahedral paramagnetic forms .308 The Platinum Metals.-The complex fluorides of ruthenium have been further investigated. Ruthenium and bromide trifluoride react vigorously a t room temperature forming RuBrF,, i.e., (BrF,)+(RuF,)-, from which ruthenium pentafluoride is readily obtained by heating at 120" in a vacuum. Mixtures of potassium bromide and ruthenium react with bromine trifluoride to form the new complex, potassium hexaffuororuthenate(v), KRuF,. With water, these complex salts of quinquevalent ruthenium evolve oxy- gen and form a hexafluororuthenate(1v) : ~ R u F , ~ - + 6H,O = 4RuFG2- + 4H30+ + 0,. The simultaneous formation of some ruthenium tetroxide is accounted for by the disproportionation reaction : 309 4Ru(v) _t Ru(vi1r) + 3Ru(1v). What appears to be a remarkable co-ordination compound of palladium(1) has been obtained from 2-phenylisophosph- A4 indoline (IX) and potassium palladochloride, having the j\/j/r..nl composition (C1,HI3P),,PdC1. Under different conditions the ( 1x1 normal complex ( Cl4HI3P),PdCl, is formed. The colourless complex of palladium@), which is dimorphic, melts to a scarlet liquid. Its solutions in warm ethanol or acetone are bright yellow, and on boiling become bright red. These colour changes are reversible and suggest dissociation, but molecular-weight determinations in boiling solvents indicate a six-fold association to [(Cl,H13P),PdC1],.310 Two series of isocyanide complexes of palladium, Pd(CNR),X, and Pd(CNR)4X2, have been obtained. Compounds of the first type, which are 303 R. 0. West, J , , 1954, 395, 678. 305 F. 1'. Dwyer, N. S. Gill, E. C. Gyarfas, and I;. Lions, J . ,4?ner. Chem. SOL., 1964, 307 L. Sacconi, Gazzetta, 1953, 83, 884, 894; Z. anorg. Cheni., 1954, 275, 449. 308 H. C. Clark and A . L. Odell, Chew. and Iwd., 1954, 1510. 30D M. A. Hepworth, R. D. Peacock, and P. L. Robinson, J . , 1954, 1197. 310 F. G. Rlann, I. T. Millar, and F. H. C. Stewart, ibid., p. 2833. 304 I d e m , Naiurr, 1964, 173, 1187. 76, 383. 30G L. D. Dyer, H. S. Borie, and G. 1'. Smith, ibid., p. 1499. Pu bl is he d on 0 1 Ja nu ar y 19 54 . D ow nl oa de d by U ni ve rs ity o f C al if or ni a - R iv er si de o n 29 /1 0/ 20 14 1 7: 30 :3 3. View Article Online http://dx.doi.org/10.1039/ar9545100118 152 INORGANIC CHEMISTRY. soluble in chloroform, have been reduced to derivatives of palladium(O), Pd(CNR),. These are probably polymeric, and are insoluble in solvents other than pyridine and nitrobenzene, in which they are decomposed to the metal ; with iodine, Pd(CNR),I, is formed.311 Reduction of pentamminoiridium bromide, (NH3)&Br, and of tetr- amminoplatinum dibromide, (NH,),PtBr,, with potassium in liquid ammonia gives pentamminoiridium (0) which is insoluble in ammonia, and tetr- amminoplatinum(0) , respectively. Decomposition results in formation of the metal and ammonia.312 Dichlorodicarbonylplatinum(11) can be obtained readily from platinum(rr1) chloride and carbon monoxide at 125" under high pressure. The pure com- pound, PtCl,(CO), loses carbon monoxide irreversibly in a vacuum. Further evidence in favour of the cis-configuration has been obtained.313 cycZoPropane appears to form compounds with platinum analogous to the normal olefin compounds. Thus chloroplatinic acid in acetic anhydride absorbs cyclopropane rapidly, forming (PtC1,,C3H6), and probably HPtC13,C3H,,H20, from which cyclopropane is evolved on treatment with potassium cyanide. Potassium bromoplatinite, K2PtBr4, and potassium nitritoplatinite, K,Pt(NO,),, form mixed cis- and trans-forms of the complex K,[Pt(NO,),Br,] which were found to undergo the following reactions : Pyridine forms the stable complex PtC1,1C,H6,2py.314 NH3 3C.I K2[Pt (NO,),Br,] _t trans-Pt (NO,),(NH,), -+ trans-Pt (NH,),T, Radioactive tracer techniques have been used to investigate exchange reactions between chloroplatinite and chloroplatinate ions. The catalysed exchange reactions are interpreted in terms of a chloro-complex of Pt (111) .31G There is some evidence for the existence of a perceptibly volatile platinum silicide, which may be responsible for attack on platinum in some high- temperature experiments in which both silica and platinum are used.317 G. E. COATES. F. GLOCKLING. 311 L. Malatesta, Atti Accad. naz. Lincei, Rend. Classe Sci.fis. mat. nat., 1954, 16, 364. 312 G. W. Watt, M. T. Walling, and P. I. Mayfield, J . Amer. Chem. Soc., 1953, 75, 313 J. M. Lutton and R. W. Parry, ibid., 1954, 76, 4271. 314 C. F. H. Tipper, personal communication. 315 A. I. Dobroborskaya and G. A. Shagisultanova, Izzvest. Akad. Nauk S.S.S.R., 316 R. L. Rich and H. Taube, J . Amer. Chem. Soc., 1954, 76, 2608. 317 R. E. Carter and F. D. Richardson, Research, 1954, 7, S3. 6175; G. W. Watt and P. I. Mayfield, zbid., p. 6178. Odtel. Khim. Nauk, 1953, 968. Pu bl is he d on 0 1 Ja nu ar y 19 54 . D ow nl oa de d by U ni ve rs ity o f C al if or ni a - R iv er si de o n 29 /1 0/ 20 14 1 7: 30 :3 3. View Article Online http://dx.doi.org/10.1039/ar9545100118