7 F CI Br I At and Noble Gases By M. J. K. THOMAS Chemical Laboratories University of London Goldsmiths' College London SE74 6NW 1 Introduction This chapter follows the format of last year in reviewing developments in the chemistry of the halogens and the noble gases that have appeared in the literature over the past year. The XIth International Symposium on Fluorine Chemistry was held in Berlin 5-9 August 1985 and included 13 plenary lectures. The abstracts of all papers and posters presented at this meeting can be found in reference 1. 2 Interhalogens and Related Ions The preparation of iodine on an industrial scale from brine has been investigated. The specificity and rate of oxidation of I- by hydrogen peroxide in the presence of catalytic amounts of iron(I1) sulphate is unaffected by large concentrations of C1- and Br-.'H and 19F n.m.r. spectroscopy and gas chromatography have confirmed that the oxidizing solution obtained from the reaction between F2 and NaOAc contains a single compound with a structure MeCOOF.3 Hypervalent iodine oxida- tion using PhI( OAc), of chromium tricarbonyl complexes of benzocycloalkanones and acetophenone occurs stereoselectively and regiospecifically to yield the Cr( C0)3 complex of the derived a-hydroxy dimethyl a~etal.~ I2 reacts with Ph,P=C=PPh in molar ratios of 1 1,2:3 and 1 :2 to give salt-like products containing the (Ph3P),CI+ cation and I- and/or If- anion^.^ The formation of a stable three-membered cyclic bromonium ion has been confirmed in the bromination of adamantylideneadamantane in CH2C12 (equation 1).6 The associated Br3-counterion forms a close contact with the Br+ which is suggestive of an ' Xlth international Symposium on Fluorine Chemistry J.Fluorine Chern. 1985 29. ' H. H. Weetall and W. Hertl Znorg. Chim. Acta 1984 104 119. D. Hebel 0.Lerman and S. Rozen J. Fluorine Chem. 1985,30,141; E. H. Appelman M. H. Mendelsohn and H. Kim J. Am. Chem. Soc. 1985 107 6514. R. M. Moriarty S. G. Engerer 0. Prakash I. Prakash U. S. Gill and W. A. Freeman J. Chem. SOC. Chem. Cornmun. 1985 1715. H. Schmidbauer Chr. Zybill D. Neugebauer and G. Muller Z. Naturforsch. Teil B 1985 40,1293. H. Slebocka-Tilk R. G. Ball and R.S. Brown I. Am. Chem. Soc. 1985. 107 4505. 175 176 M. J. K. Thomas intimate ion-pair.The mercury( 11) oxide-tetrafluoroboric acid system supported on silica gel reacts with pyridine in the presence of iodine to give I(PY)~BF~.' If this compound is allowed to react with alkenes in the presence of a nucleophile the corresponding 1,2-iodofunctionalized compounds are formed. Infrared studies of the complexes formed between ICl and carbonyl bases in dilute heptane solutions suggest the existence of two 1 :1 stereoisomeric complexes (1) and (2).8 When ICl is in excess a 1:2 complex (3) appears. The complexes c1 c1 R' I/-/ \ #I/ R' \ R' \ /'I /=ox c=o--ICI R2 I R2/ R2/c=o 'C1 formed between ClF and a variety of oxygen-containing bases have been character- ized by matrix-isolation infrared spectros~opy.~" The results suggest that the interac- tion in the complex is through the C1 of C1F to the oxygen of the base.Infrared spectra of mixtures of H2S and C12 or Br in low temperature matrices indicate that as well as the formation of the H2S-..X2 complexes reaction occurred between the two components to give the corresponding hydrogen halides.gb Species such as HSC1 HSBr and BrSSBr were also tentatively identified. Solutions of I in benzene toluene and mesitylene were excited at 532 nm and studied by picosecond spectros- copy. The results imply the formation of the radical-ion pair [Art IT] as an intermediate." Ab initio calculations have predicted that the T-shaped molecules C12F2 C13F and C14 are thermodynamically stable to atomization but not to dissociation into the appropriate mixture of C1F and Cl,." Quantitative yields of C1F5 can be obtained from the reaction of ClF3 and O,F at -78 OC.I2 The reaction illustrates the general utility of 02F2 in high-valent fluoride synthesis.Short-lived intermediates IF4[0C2H4Me,0]X and stable chelates IF3[0C2H4Me,0] and IF[OC,H4Me,0] (n = 0-4 X = SiMe3) are formed in reactions between IF and a,P-trimethylsily- lated ethanedi01ates.l~ Polyhalide anions containing Br and I have been prepared with 2,2'-bipyridylium (BPH+) as cation.14 In BPH+12 Br; the anion is V-shaped. It can be thought of as two IBr molecules linked to Br- with the longer I-Br bonds at the central atom. The I,Br2- anion is built up from IBr,- connected by I molecules. The reactions between R3P (R = butyl octyl and cyclohexyl) and I, Br, and ICl in MeCN have ' J.Barluenga J. M. Gonzalez P. J. Campos and G. Asensio Angew. Chem. ht. Ed. Engl. 1985 24 319. M. Berthelot M. Helbert and C. Laurence Can. J. Chem. 1985 63 958. 9a N. P. Machara and B. S. Ault Inorg. Chem. 1985 24 4251. 9b U. P. Agarawal A. J. Barnes and W. J. Orville-Thomas Can. J. Chem. 1985 63 1705. 10 E. F. Hilinski and P. M. Rentzepris J. Am. Chem. SOC.,1985 107 5907. C. J. Marsden J. Chem. SOC.,Chem. Commun. 1985 786. 12 S. A. Kinkead L. B. Asprey and P. G. Eller J. Fluorine Chem. 1985 29 459. l3 H. J. Frohn and W. Pahlmann J. Fluorine Chem. 1985,28 191. l4 A. Parlow and H. Hartl 2.Naturforsch. Ted B 1985 40,45. F Cl Br I At and Noble Gases fx2 tX2 x2 R3P __* R3PX -+ R,PX+X-R3PX'X; (2) been studied conductometrically.'5 There is evidence for the formation of 0.5 :1 1 :1 and 2 :1 adducts (equation 2).The F; ion is stable with respect to F-and F by about 45 kJ mo1-'.16 The formation of the trihalide anions Cl, ICl; 12C1- and 13 from the parent halogen molecules has been studied in methanol." Iodide has a much greater affinity than chloride towards halogen molecules and the reaction is best described as a redox reaction whereas the reaction between chloride and halogens is a simple addition. The vibrational spectra of the new compounds CsF-3BrF3 RbF.3BrF3 and RbF-2BrF3 suggest that they are salts having the general formulae M+Br,FL0 and M+Br2F;.'* 3 NobleGases The reactions of XeF with Me,X (n = 3 X = N P As or Sb; n = 2 X = 0 S or Se; n = 1 X = C1 Br or I) have been s~rveyed.'~ The reactions all proceed smoothly the rate of reaction reflecting the basicity of the substrate Me,X.The difluoride Me,XF is formed in most cases when X = P As Sb Se or I. Where X is N 0 or S cleavage of C-H bonds to form CH2F derivatives is the main path and cleavage of C-X bonds to form MeF when X is C1 or Br. Reaction of Xe(OTeF,) with the halogenoalkanes CF,=CFCl CF2=CC12 and CF,=CFH results in the addition of two TeF,O groups to the double bond." For per- fluorobutadiene saturation of both double bonds occurs to give 1,2,3,4-(TeF50)4C4F6. The Cs' salts of the anions [XeOF,]- and [(XeOF4),F]- have been prepared and characterized.21 The Raman spectrum of XeOF; is consistent with a stereochemi- cally active lone-pair of electrons on the Xe resulting in a distorted octahedral arrangement (4).The structure of [(XeOF,),F]- (Figure 1) consists of octahedra of O=XeF4E (E = lone pair) linked through three fluorine bridges. The trigonally bonded fluorine is positioned above the plane defined by the three xenon atoms. Stable oxygen-bonded xenon(I1) and xenon(1v) derivatives of the O=IF40 group have been observed in solution [(5)-(9)] and the solid derivative cis,cis-Xe(OIF40) (10) isolated.'* lZ9Xe n.m.r. chemical shifts have established that the O=IF40 group is the second most electronegative group after fluorine. l5 G. S. Harris and J. S. McKechnie Polyhedron 1985 4 115. 16 P. A. Cahill C. E. Dykstra and J. C. Martin J.Am. Chem SOC.,1985 107 6359. L.-F. Olsson Znorg. Chem. 1985 24 1398. 18 L. Stein J. Fluorine Chem. 1985 27 249. 19 A. M. Forster and A. J. Downs Polyhedron 1985 4 1625. 20 C. J. Schack and K. 0. Christie J. Fluorine Chem. 1985 27 53. 21 J. H. Holloway V. Kaucic D. Martin-Rovet D. R. Russell G. J. Schrobilgen and H. Selig Znorg. Chem. 1985 24,678. 22 R. G. Syvret and G. J. Schrobiligen J. Chem. SOC.,Chem. Commun. 1985 1529. M. J. K. Thomas Figure 1 Structure of the [(XeOF,),]-anion FF F-1-F740 I/ O=I-0 ‘ F/IF Xe \ F P 4 Hydrogen Halides Experimental measurements of the gas-phase ion equilibria shown in equations 3 and 4 with a high-pressure mass spectrometer provide a complete set of hydrogen- bond dissociation energies and free energies for the hydrogen bihalide ions.23 For XHX-+X-+ HX there is a systematic decrease in the bond enthalpy values in the order F > C1 > Br > I.For X-HY where X-is kept constant and HY changed the general trend is that the bond energy increases as HY is changed from HF to HI paralleling the trend in gas-phase acidity of HY. X-+ HX -+ XHX-(3) X-+ HY -* XHY-(4) Theoretical studies of hydrogen-bonded compounds of the hydrogen halides have been used to calculate hydrogen-bond energies and equilibrium ge~metries.~~ For complexes of the type Me,NH~-,,..-F-H and Me,NH -,... H-F the conventional one-proton hydrogen-bond (11) is predicted to be more stable than two- and three-proton hydrogen-bonds [( 12) (13)]. In hydrogen-bonded complexes of HX 23 G.Caldwell and P. Kebarle Can.J. Chem. 1985 63 1399. 24a A. Hinchliffe J. Mol. Strucr. 1985 121 201. 24b H.T. Flakus and R. J. Boyd Can. J. Chem. 1985 63 1562. F Cl Br I At and Noble Gases (11) (12) (13) with methyl-substituted cyclopropanes the hydrogen-bonding occurs at the C-C bond adjacent to the substitution site.25 The vCIPH band in the solution infrared spectra of R2S and R,Se complexes with HC1 appears as a broad band. This feature may be assigned to complexes having 1:1 and 1:2 stoicheiometry.26 Matrix-isolation studies of complexes of the hydrogen halides with a wide variety of molecules have continued. Co-deposition of Ar/ether and Ar/HF (ether = Me20 or Et20) at 12 K results in a 1:1 complex in which the HF is hydrogen-bonded to (14) a lone pair on the ether oxygen.27a Annealing of the sample produces a 1:2 complex (14).Similar complexes are found for ethylene oxide and HX.27b HF forms 1 :1 complexes with conjugated dienes in which the a,cid hydrogen oscillates between regions of maximum .rr-electron density of both bonds.28 Spectroscopic evidence for the formation of 1:1 1:2 and 2 1 complexes of HX and H2Y (X = F C1; Y = S Se) has been presented.29 A stable reverse complex HF.-.HSH was also characterized in this study. Co-deposition of RCN and HF in Ar produces complexes of the form R-CN. -H-F.30 On warming the matrix above 18 K 1:2 and 1 :3 complexes were obtained. Irradiation of oxygen-swept aqueous solutions of HBr in the presence of catalytic amounts of anthraquinone derivatives gives molecular bromine with quantum yields of up to 0.07.3' 5 0x0-compounds The correlation between 0-F bond energies and I9F n.m.r.chemical shifts in fluoro-oxo compounds reported last year has been extended over a wider range of compounds. A plot of 0-F bond dissociation energy (D)us. n.m.r. chemical shift (4) is S-shaped. The plot may be fitted to the expression D = 37.1 + 18.1 tanh [(222.7 -4)/117.5] (5) This expression provides a useful way of obtaining the 0-F bond energies of fluoro-oxo compounds from readily accessible spectroscopic data.32 25 C. E. Trusscot and B. S. Auk J. Phys. Chem. 1985 89 1741. 26 M. Graindourze and G. Maes J. Mol. Spectrosc. 1985 114 97. 27 a L. Andrews G.L. Johnson and S. R. Davis J. Phys. Chem. 1985 89 1710. 27 b P. Bernadet and L. Schriver J. Mol. Struct. 1985 130 193. 28 K. 0. Patten and L. Andrews J. Am. Chem. Sac. 1985 107 5594. 29 G. Maes and M. Graindourze J. Mol. Spectrosc. 1985 113 410; R. T. Arlinghaus and L. Andrews Inorg. Chem. 1984 24 1523. 30 S. R. Davis and L. Andrews J. Mol. Spectrosc. 1985 111 219. 31 B. Fuchs W. J. W. Mayer and S. Abramason J. Chem. SOC.,Chem. Commun. 1985 1711. 32 E. Ghibaudi A. J. Colussi and K. 0.Christe Znorg. Chem. 1985 24 2868. 180 M. J. K. Thomas HOCl can be prepared on a laboratory scale from the reaction of Cl with aqueous CaC03. It should be used before it equilibrates to Cl2O and water.33 Electronic spectra for 01- HOI and H,OI+ in aqueous media have been reported.34 Evidence is presented for the disproportionation of OI-/HOI/H201+ to I-and 10-4in basic media and to 1 and IOW4in acid media.I reacts with O3 in the gas phase to form a solid iodine oxide having the stoicheiometric composition 1409.35The reaction rate is first order with respect to both I2 and 03.Co-deposition of Me1 and O3 in Ar at 17 K leads to the formation of a molecular complex which on irradiation photodissociates to MeI0.36"Further photorearrangements occur as show,n in Scheme 1. Similar reactions occur between CF31 and O3 (Scheme 2),36bThe disproportionation of Cloy has been studied in HC104 at 25 0C.37The results are consistent with at least three reaction paths the first is catalysed by C1-ions the second gives a second-order rate,law,and the third is catalysed by iron(rI1).The complete mechanism can be represented by Scheme 3. Aminolysis of C1207with N,N'-disubstituted diamines gives new compounds containing two perchloryl groups in the molecule.38 HI \ / '\ H-C 'H \/ -9 0 H \ hu H-C-I / \ 290-420nm I 0 \ H I \/ H-C-0 / H/ H H HTI \ warming \ ' /c=o - c& / H 'H H \ I \ Scheme 1 The structures of ST(XO~)~= C1 Br) show that the ClO ions and one of the (X two crystallographically non-equivalent BrO ions are distorted.39 The Raman spectra of solutions of alkali metal perchlorates in DMSO and water can be explained on the basis of formation of ion pairs of MC104 in DMSO and ion hydrates in water.40Anhydrous transition-metal perchlorates and their chloryl and nitryl salts C102M(C104)3and (N02)2M(C104)4(M = Ni Co Cu) have been prepared by the 33 C.A. Ennis and J. W. Birks J. Phys. Chem. 1985 89 186. 34 J. Paquette and B. L. Ford Can. J. Chem. 1985 63 2444. 3s A. C. Vikis and R. MacFarlane J. Chem. Phys. 1985,89 812. 360 M. Hawkins and L. Andrews Inorg. Chem. 1985 24 3285. 36b L. Andrews M. Hawkins and R. Withnall Znorg. Chem. 1985 24 4234. 37 G. Schmitz and H. Rooze Can. J. Chem. 1985 63 975. 38 W. Hennricks and J. Jander 2.Anorg. Allg. Chem. 1985 526 186. 39 H. D. Lutz W. Buchmeier E. Alici and W. Eckers 2. Anorg. Allg. Chem. 1985 529 46. 40 M. I. S. Sastry and S. Singh Can. J. Chem. 1985 63 1351.181 F Cl Br I At and Noble Gases F \ ,c-I--0-0 \ FF/ 0 F \ ,c-0 F / \I F L J 11 I F 240-420 nm ,c-I \ + 02 -F / \o F F \ /c=o F' F I\ F Scheme 2 Cl02 c1-/ HClO -ClZO2 HClO2 y* cloy c1 (Fe) c1-c10 c10; Scheme 3 action of C1206 on the corresponding metal chloride or nitrate.41 The vibrational spectra of M(C104)* are consistent with a strong metal-perchlorate interaction explained by two types of bidentate perchlorate group in CU(C~O~)~ and tridentate coordination in the nickel and cobalt compounds. 6 Structural Chemistry of Solid Complex Halides Containing Main-group Elements Four different crystalline compounds can be obtained from the PCl,-SnCl system viz.(PC14)2(SnC16) (PCLJ3( SnCI,)( pC16) (pCI4)2( Sn2cl,J and (PCI,)(S~CI,).~~ 41 J.-L. Pascal J. Potier and C. S. Zhang J. Chem. Soc. Dalton Trans. 1985 297. 42 J. Shamir S. Luski A. Bino S. Cohen and D. Gibson Inorg. Chem. 1985 24 2301. M. J. K. Thomas All four compounds are ionic with tetrahedral PClt cations and appropriate anions. Similar reactions between PCl and either SbC15 or NbCls in POC13 or SOCI lead to the corresponding SbC1 or NbC1 compounds.43 An X-ray crystal structure determination of Fe(TPP)(sbF,).C,H,F shows that the complex is not ionic.@ The hexafluoroantimonate ligand coordinates to the iron in a monodentate fashion with an Fe-F bond length of 0.2105 nm. The spin state is nearly pure S = 3/2. The mean S-Cl stretching frequency of SCl in a series of SC13X salts is proportional to the mean S-C1 distance the force constant and the S-a-anion di~tance.~' Se612(ASF,),.2S02 has a cation which contains a hexaselenium ring of chair conformation with iodine substituents in the axial 1,Cpositions (Figure 2).46 The structure of TeCI has been determined by electron diffraction completing the series XC1 (X = 0 S Se Te).47 The structural data are in Table 1.Figure 2 The structure of the Se61;+ cation Table 1 Structural parameters for the chalcogen dihalides Compound oc1 El-C1 (pm) 169.3 ClEzl (") 11 1.2 Cl.-.Cl(pm) 280 SCl 200.5 103.0 314 SeCl 215.7 99.6 330 TeCl 232.9 97.0 349 7 Group IV Halides A6 initio molecular orbital calculations on SiF show that it is bent in both its ground and excited states.No minimum in the calculations could be found for F,Si-SiF,; the stable species is singlet :FSiSiF3.48 Photoelectron spectroscopy has been used to optimize the synthesis by various routes of SiC12?9 Insertion of SiH2 into Si-F bonds has been studied using ab initio calculations." When SiH 43 J. Shamir S. Luski A. Bino S. Cohen and D. Gibson Inorg. Chim. Acta 1985 104 91. 44 K. Shelly T. Bartczak W. R. Scheidt and C. A. Reed Inorg. Chem. 1985 24 4325. 4s R. Minkwitz K. Janichen H. Prenzel and V. Wolfel Z. Naturforsch. Teil B 1985 40 53. 46 J. J. Passmore P. S. White and C.-M. Wong J. Chem. SOC. Dalton Trans. 1985 1178. 47 L. Fernholt A. Haaland H. V. Volden and R. Kniep J. Mol. Struct. 1985 128 29.48 K. Krogh-Jespersen J. Am. Chem. SOC.,1985 107 537. 49 H. Bock B. Solouki and G. Maier Angew. Chem. Int. Ed. Engl. 1985 24 205. so H. B. Schlegel and C. Sosa J. Phys. Chem. 1985,89 537. F Cl Br I At and Noble Gases approaches SiH,F a stable complex (15) is formed in which the lone pairs on F donate into an empty p-orbital on the silylene group before insertion occurs. 1 :1 molecular complexes are formed between MeCN or HCN and MF4 (M = Si,Ge) in Ar matrices at 14K514 All of the complexes are bound through the N atom of the -CN group to the Si or Ge atom. 1 :1 complexes are also formed between the fluorides and the cyclic ethers (CH2),0 (n =2").'lb SiF undergoes exchange reactions with PC13 and P0Cl3 at 500-600 "C to give mixed chlorofluorides of silicon and pho~phorus.~~ Unbranched chlorinated tri- tetra- and penta-silanes with internal hydrogen substituents can be prepared from the corresponding phenyl silanes by cleavage of the phenyl groups using HCl/AlC13.53 SiC14 reacts with R2NPH2(R =SiMe,) according to equation 6.54 (Me,Si),NPH +SiCl -+(Me,Si),N-P(H)SiCl, 1 -HSiCI H SiC1 \/ P-P /\-(Me3Si),N N(SiMe& The structure of SiH3F at 96 K comprises chains of molecules formed by inter- molecular F- ..Si interaction^.^^ There are no close F.-.Hcontacts and a lengthening of the Si-F bond relative to the gas-phase value is observed. The structures of the cyclic compounds Si,Brlo and Si5IlO at room temperature and low temperature are isomorphous and show Si,-ring conformations intermediate between envelope and SnF2 reacts with AsF5 and SbF in a 2 :1 ratio to give salts containing the Sn2Fl cation." 8 Fluoro- and Perfluoro-carbon Derivatives of Nitrogen The gas-phase structure of perfluoronitrosocyclobutane has been determined by electron diffraction measurement^.^^ Of the six possible conformations for this compound the equatorial-exo conformer (16) is slightly favoured over the axial-em conformer but a mixture of both is likely.An X-ray photoelectron spectroscopic 510 B. S. Auk J. Mol. Struct. 1985 130 215. 5'bB. S. Ault J. Mol. Struct. 1985 127 343. 52 B. S. Suresh and D. K. Padma J. Fluorine Chem. 1985 29 463. 53 H. Hengge and F. K. Mitler 2.Anorg. AIIg. Chem 1985 529 22. 54 E. Niecke W.Guth and M. Lysek 2. Naturjorsch. Teil B 1985 40,331. 55 A. J. Blake E. A. V. Ebsworth S. G. D. Henderson and A. J. Welch Acta Crystallogr. Sect. C 1985 41 1141. 56 Ch. Kratsk H. Hengge H. Stuger and A. L. Rheingotd Acta Crystallogr. Sect. C 1985 41 824. 57 T. Birchall J. E. Veknis B. Frlec D. Gantar and D. Hanzel J. Fluorine Chem. 1985 27 61. H.M. Marsden H. Oberharnmer and J. M.Shreeve Inorg. Chem. 1985 24 4756. M. J. K. Thomas study of CF3NC indicates that it is almost as strong as CO as a n-acceptor ligand.59 The results also give an isomerization energy for the reaction CF3NC to CF,CN of -97kJ mol-'. Hydrogen halide addition to CF,NC gives both isomers of the compounds CF,N=CHF CF,N=CHCI and CF,N=CHBr with the E-isomer predominant.60 All of these compounds dimerize slowly to give CF,N=C(H)N(CF,)(CX,H).CF3N=C(Br)SF can be prepared by addition of SF5Br to CF,NC. The pyrolysis of F2HCN3 leads to the formation of N2 + FCN + HF.61 The pyrolysis is complete at 940 K and may provide a convenient route to pure FCN. (CF3)2 NONO reacts with (CF3),M (M = P As Sb) to give mainly the corre- sponding bis(trifluoromethy1)nitroxyl derivatives.62" (CF,),P gives (CF,),NOP(O)-(CF3)2 and (CF3)2NN0. (CF,),As gives (CF,),NNO in good yield as well as (CF3)2NOA~(CF3)2, CF3N=CF2 COF2 and a polymeric solid. (CF3)2AsX (X = F C1) reacts with (CF,),NO to give (CF,),NOAs(CF,)X and (CF3)2NOCF3.62b With X = Br the final product is [(CF3)2N0]3As(CF3)2. 9 Halides of Phosphorus Arsenic and Antimony and their Derivatives The molecular structure of PC12F3 in the gas phase has the chlorine atoms in equatorial positions as predicted from other experiment^.^^ Although no evidence could be found for Berry inversion isomers in which chlorine atoms are in axial positions can not be discounted.The low-temperature structure of C6F5PC1 has been confirmed by "Cl n.q.r. as trigonal bipyramidal with the aryl group in an axial position.64 At temperatures between -20 and 15 "C F3CP=CF2 reacts as a dienophile with cyclopentadiene butadiene and 1,3-~yclohexadiene to give the Diels- Alder adducts in high yield.65 The reaction of PCl, PSCl, POCl, and PC15 with urethane in 1:1 and 1 :2 ratios gives compounds of the type C1,-,P[HNC(O)OEt] and CI,-,P(X)- [HNC(O)OEt] (X = 0 S or C1; n = 1 or 2).66 The basic methanolysis of (CF3PCF2)2 has been studied and new bis(phosphino)difluoromethanes and (difluoromethy1)phosphines identified.67 The reaction of PCI with alkylammonium fluorides in the presence of secondary amines gives adducts PF,.NHR2 instead of 59 D.B. Beach W. L. Jolly and D. Lentz Inorg. Chem. 1985 24 1892. 60 D. Lentz and H. Oberhammer Inorg. Chem. 1985 24 4665. 61 H. Bock and R. Dammel Inorg. Chem. 1985 24 4427. 62a H. G. Ang and K. K. So J. Fluorine Chem 1985 27 411. 62b H. G. Ang and K. K. So J. Fluorine Chem. 1985,27,433. 63 R. J. French K. Hedberg J. M. Shreeve and K. D. Gupta Inorg. Chem. 1985 24 2774. 64 K. B. Dillon and J. Lincoln Polyhedron 1985 4 1333. 65 J. Grobe and D.LeVan 2.Naturforsch. Teil 8 1985 40,467, 66 R. P. Narain and M. Z. Siddiqui Polyhedron 1985 4 467. 67 A. B. Burg Inorg. Chem. 1985 24 148. F Cl Br I At and Noble Gases hexafluorophosphates.68 In the additional presence of alcohols or phenols ROPFS is formed. Alkyl diaminodifluorophosphoranes react with BF,.OEt to give the corresponding alkyl diaminodifluorophosphonium tetrafl~oroborates.6~ The structure of the As2C1g- anion of (PPh,),[As2C18] is centrosymmetric with two square pyramids sharing basal edges (Figure 3). The As-C1 bond lengths show a marked ~rans-effect.~' The Raman spectrum of (/3)6SbF3.5SbF5is identical to that of a compound designated SbF5.SbF3(/3) by earlier The structure consists Figure 3 The structure of the As,Cl;-anion 20 2.1 Figure 4 Bond distances (pm) and angles (") of the Sb,F:T cation in (p)6SbF3.5SbF of discrete Sb6F:T cations and SbF anions.The cation (Figure 4) can be considered as being built up of Sb2Ff and SbFl units. A series of adducts between BiF and SbF5 having formulae BiF5.(SbF5) (n = 1.5 2 or 3) and (BiF5),SbF (n = 2 3 or 20.6) have been prepared.72 The vibrational spectra of BiF5(SbFS) are all similar and indicate the presence of BiF5 and SbF5 groups linked by cis-bridging fluorines. (BiF5),SbF5 are isomorphous with polymeric trans-bridging BiF5 groups. 68 L. Reisel and M. Kant Z. Anorg. Allg. Chem. 1985 530 207. 69 J. Svara and E. Fluck 2.Anorg. Allg. Chem. 1985 529 137. 70 A. T. Mohammed and U. Muller Actu Crystullogr. Sect. C 1985 41 329.71 W. A. Shantha Nandana J. Passmore and P. S. White J. Chem. Soc. Dalton Trans. 1985 1623. 72 G. S. H. Chen J. Passmore P.Taylor T. K. midden and P. S. White J. Chem. SOC. Dalton Trans. 1985 9. M. J. K. Thomas 10 Perfluoroalkyl and Alkyl Sulphur Selenium and Tellurium Halides CF3SI can be prepared from CF3SH and N-iodos~ccinimide.~~ It behaves chemically like ICl and at higher temperatures it decomposes to CF3SSCF3 and I,. Hydrolysis of CF3-,,C1 SCI with water gives the corresponding thiosulphinates CF3-,Cl,SS(0)CF3-,C1,, and thiosulphonates CF3-,Cl,SSO2CF3-,C1, as stable intermediate^.^^ The cyclic compounds R&S2 (17) (R = F C1 Br and CF,) have attracted considerable attention this year.75 Scheme 4 illustrates some of the reactions that these compounds undergo.F4C2S2 reacts with AsF or SbF5 to give the ion ( 18).76" The cation has mm symmetry with no short intermolecular interactions. The C-F and C-S bonds to the cationic carbon are significantly shorter than the R RO CI I I R,C=S ACI-C-S-Cl + Cl-C-S-C1 It I I R R I 1 I I I I I Scheme 4 S S / \+ FZC C-F MF 'S' 73 R. Minkwitz and R. Lekies Z. Anorg. Allg. Chem. 1985 527 161. 74 A Haas W. Wanzke and N. Welcman 2. Naturforsch. Teil B 1985 40,32. 75 A. Elsasser W. Sundermayer and D. S. Stephenson Chem. Ber. 1985 118 116; A. Elsasser and W. Sundermayer Chem. Ber. 1984 118,4553; R. Schark and W. Sundermayer Chem. Ber. 1985,118,1415. 76a A. Waterfeld and R. Mews Chem. Ber. 1985 118 4991.F Cl Br I At and Noble Gases other C-F and C-S bonds.76b The sulphoxylates S[OCH(R)CF,] and the disul- phides S2[0CH(R)CF3] (R = CF, H) are obtained by reacting SC12 or S2C12 respectively with the lithium alkoxides LiOCH( R)CF3.77 C12 reacts with S[OCH2CF,l2 to give C1S(0)OCH2CF3 and CF3CH2C1 whereas the S-S bond is cleaved in the corresponding disulphide. The structure of ClSCOCl has been deter- mined in the gas phase at 35 "C by electron diffraction (Figure 5).78 The major Figure 5 Bond distances (pm) and angles (") in ClSCOCl CI F F I 'As F'l F Figure 6 The structure of CF,SCl + AsF conformer has C1 atoms anti to each other. A small amount of a second form may also be present. CF,SCI;AsF (Figure 6) has been prepared by three methods (equations 7-9) and characterized by infrared Raman and 19F and 13C n.m.r.79 so2 2CF,SCl + 3AsF + C1 -2CF3SCl;AsF + AsF (7) CF3SCl + AsF + ClF -CF,SCl;AsFi (8) 2CF3SCI + AsF + Cl,F+A,F -2CF3SCl;AsF (9) The first species with a sulphur-carbon triple bond CF,C_SF, has been prepared by dehydrofluorination of CF3CH=SF4 or CF3CH2SF5." It is a colourless gas having a melting point of -122.8 "C and an estimated boiling point of -15 "C.The molecule has a very short C-S bond of 0.1393 nm and an almost linear C-CES geometry. It reacts with HF to form the starting materials and on slow heating to -20°C it dimerizes to give the butene CF,(SF,)C=C(CF,)SF with a trans-configuration. The new alkenes CF3SF4CF=CF2 and CF,SF4CH=CF2 are obtained by the dehydrochlorination of CF3SF,CHFCF2Cl and CF3SF4CH2Cl respectively.*l A series of CF,SF4-substituted compounds can be prepared from the alkenes.76 b J. Antel K. Harms P. G. Jones R. Mews G. M. Sheldrick and A. Waterfeld Chem. Ber. 1985 118 5006. 77 H. Hacklin E. Baltruschat and G.-V. Roschenthaler Z. Anorg. Allg. Chem. 1985 522 155. 78 Q. Shen and K. Hagen J. Mol. Struct. 1985 128 41. 79 R. Minkwitz U. Nass A. Radunz and H. Preut Z. Naturforsch. Ted B 1985 40 1123. 80 B. Potter K. Seppelt A. Simon E.-M. Peters and B. Hettich J. Am. Chem. SOC.,1985 107 980. 81 K. D. Gupta and J. M. Shreeve Inorg. Chem. 1985 24 1457. 188 M. J. K. Thomas Ethynylsulphur pentafluoride SF,C_CH can be prepared by the dehydrobromina- tion of SF5CH=CFBr with a yield of ca.50% .' It can also be prepared in a four-step synthesis but the 'overall yield is then only 9%. Infrared spectroscopy shows that SF has approximately the same electronegativity as chlorine. The molecular struc- ture of CF3SF is based on a slightly distorted ~ctahedron.~ The axial S-F bond trans to CF, is shorter than the equatorial bonds and the mean S-F distance is 0.0008 nm longer than that in SF,. The gas-phase structure of monomeric (CF,),SeF has the CF ligands occupying the equatorial sites of a framework derived from a trigonal bi~yramid.~~ The change from SeF to (CF,),SeF results in an increase in the equatorial bond angle in agreement with the predictions of the valence-shell electron-pair repulsion model.Selenium and tellurium bis(trithiocarb0nates) react with Br or I to give the corresponding halogenoselenium- and halogenotellurium-trithiocarbonates.85 Reac-tion of (C2F5),Te and XeF in a slurry of S0,ClF gives (C2FJ2TeF2 which has a trigonal-bipyramidal geometry in which the lone pair and the organic groups are equatorial.' C2F,TeF3 can be obtained from C,F5TeTeC2F and XeF,. In the structure of C2F5TeF each tellurium atom is surrounded by two terminal F atoms two bridging F atoms and a C2F5 group in an axial position around the apex of a distorted square pyramid. The geometry around the tellurium is consistent with the steric activity of a lone pair of electrons. 11 Sulphur Selenium and Tellurium Oxofluorides and their Derivatives The fluorinating ability of SOF is very similar to that of COF2.87 It replaces active hydrogen with fluorine in P-H and C-H bonds but with N-H bonds NS(0)F is formed.The 1 1 molecular complexes between SF4 SOF, and S02F with a wide variety of N-and 0-containing bases have been studied in nitrogen matrices.88 The complexes are covalently bonded from the S atom to the 0 or N atom of the base with the sulphur compound acting as a dr* acceptor of the lone pair of electrons of the base. The order of the Lewis acidity is SF4 > SOF > S02F2. The enthalpies of formation of SeC1 and SeOC1 are -184.4 and -182.9 kJ m01-l.~~ Electron diffraction measurements have demonstrated that the compound formulated as pentafluoroselenium isocyanate F5Se-N=C=O is in fact F5Se-O-C=N.90 This has been confirmed by vibrational and 77Se and 14,15 N n.m.r.spectroscopy. Raman spectroscopy indicates that solutions of SeO in HBr contain H2Se03 HSeO,Br SeOBr, SeBrT and SeB~-i-.~l The ease of formation of halogenoselenate species in aqueous HX solutions HBr > HC1 > HF correlates with the magnitude of the HX activities in water. 82 J. M. Canich M. M. Ludvig W. W. Paudler G. L. Gard and J. M. Shreeve Inorg. Chem. 1985,24,3668. 83 C. J. Marsden D. Christen and H. Oberhammer J. Mol. Sfrucf.,1985 131 299. 84 P. L. Baxter A. J. Downs A. M. Forster M. J. Goode D. W. H. Rankin and H. E. Robertson J. Chem. SOC.,Dalton Trans. 1985 941. S. Karo K. Kaga M. Ishida and T. Murai 2. Naturforsch. Teil B 1985 40 273. 86 C. Lau J. Passmore E.K. Richardson T. K. Whidden and P. S. White Can. J. Chem. 1985,63 2273. T. Mahmood and J. M. Shreeve Inorg. Chem. 1985 24 1395. 88 C. S. Sass and B. S. Ault J. Phys. Chem. 1985 89 1002. 89 H. Oppermann U. Hanke and G. Kunze 2. Anorg. Allg. Chem. 1985,530 163. 90 K. Seppelt and H. Oberhammer Znorg. Chem. 1985 24 1227. 91 J. Milne and P. Lahaie Inorg. Chem. 1985 24 840. F Cl Br I At and Noble Gases 189 This year has seen continued interest in the preparation and characterization of teflate complexes. NO+OTeF is obtained from NOCl and Hg(OTeF5)2?2 It is ionic in the solid state and in MeCN but in the gas-phase it is a covalent molecule ON-OTeF,. The OTeF; ion-donor properties of Te(OTeF,) have been studied in the presence of AsF and As(OT~F,),.~~ 12,Te n.m.r.spectroscopy has been used to characterize the mixed cations [TeF,(OTeF,),-,]+ (x = 0-3) and the neutral species TeF,(OTeF,),- (x = 0-2) and the novel anion As(OTeF,) has also been identified. Two laboratories have independently claimed the first observation of bridging -OTeF groups in the solid state. The structure of [AgOTeF5(C6H,Me)2]2 contains planar Ag202 cores with two OTeF groups bridging two Ag atoms (Figure 7). The teflate group is a much stronger ligand than perchlorate in this type of complex.940 X-Ray analysis of the structure of Au(OTeF,) suggests that the molecular units X2AuX2AuX (X = OTeF,) exist in the solid.94b 0 A Figure 7 Structure of the centrosyrnrnetric molecule [AgOTeF,(C,H,Me)212 12 Sulphur-Nitrogen Halides and their Fluorocarbon Derivatives Thiazyl pentafluorooxotellurate NSOTeF, has been prepared from NSF and B(OTeF,) or from NS+SbF and CSOT~F,.~ It is unstable and isomerizes readily to give TeF,NSO and polymeric materials.The BF,-catalysed elimination of SO2 from TeF,NSO gives F,TeNSNTeF,. The reactions of (NSCl) continue to attract considerable attention. The products of reactions between (NSCl) and Ga,96" VC1,,96b ZrClq,96c MoCl or MoC~,,~~~ Re2(C0),o,96e Ru~(CO),~,~~~ 92 J. S. Thrasher and K. Seppelt Z. Anorg. AZZg. Chem. 1985 529 85. 93 M. J. Collins and G. J. Schrobilgen Inorg. Chem. 1985 24 2608. 940 S. H. Strauss M. D. Noiret and 0. P. Anderson Znorg. Chem. 1985 24 4307. 94b P. Huppmann H. Had and K. Seppelt Z.Anorg. A&. Chern. 1985 524 26. 95 R. Hoppenheit and R. Mews Chem. Ber. 1985 118 4276. 960 P. Klinzing W. Willing U. Muller and K. Dehnicke Z. Anorg. Allg. Chern. 1985 529 35. 96 b G. Beber J. Hanich and K. Dehnicke Z. Naturforsch. Teil B 1985 40,9. 96c J. Eicher U. Muller and K. Dehnicke Z. Anorg. AZZg. Chem. 1985 521 37. 96d U. Muller P. Klingelhofer U. Kynast and K. Dehnicke Z. Anorg. AZZg. Chem. 1985 520 18. 96e D. Fenske A. Berg F. Weller and K. Dehnicke Z. Anorg. Allg. Chem. 1985 527 105. A. Berg K. Dehnicke and D. Fenske Z. Anorg. AZlg. Chem. 1985 527 111. 190 M. J. K. Thomas [RUC~(PP~,)~X]= C1 Br CN SCN or S~IC~,),~' have (X and [RUC~~(PP~,),]~~ been isolated and characterized. The reaction between (NSCl) and PPh in CH2C12 gives [Ph3PNH2]C1.CH2C12 and Ph3PNH.No thionitrosyl complexes were obtained from the reactions of (NSCl) and [ RhCl( PPh,),] trans-[Rh(CO)Cl( PPh,),] or [Rh( NO)( PPh3)3 1-Oxidative halogenation of CF,SN( SiMe3)2 with F2 or C12 gives CF,S(X)=NX (X = F Cl).99 In the chlorination reaction CF3S(C1)=NSiMe3 was isolated as an intermediate. It reacts with CF,SCl to give CF3S(Cl)=NSCF3. [S3N2Cl]+C1- reacts with Hg(SCF,) to give CF3SSN=S=NSSCF3. The products of the reactions between CF3SCl and a series of heterocyclic bases have been isolated and character- ized (Scheme 5).'0° Analogous reactions occur with CF3SO2C1 and with CF,S(O)Cl. The synthesis and stability of Me,NSF,+AsF; have been described."' The coordina- tion around the sulphur of the cation is trigonal bipyramidal and the activation energy for pseudorotation is ca.55 kJ mol-' at 35 "C. CF3S\ f'l/SCF3 QJ II CF3S SCF3 J I SCF3 I Me2Si-N-SiMe2 I HNI NH I I Me2Si-N-SiMez I SCF3 Scheme 5 13 Binary Halides of the &Block Elements The molecular structures of VC12 CrCl, and CoBr have been determined in the gas phase by electron diffraction.lo2 The first two compounds have bent structures 91 M. Gupta R. F. N. Ashok A. Mishra V. B. S. Chauhan and U. C. Aganuala J. Chem. SOC.,Dalton Trans. 1985 2449. 98 M. B. Hursthouse N. P. C. Walker C. P. Warrens and J. D. Woollins J. Chem. SOC.,Dalton Trans. 1985 1043. 99 A. Hass and R. Walz Chem. Ber. 1985 118 3248. I00 0.D. Gupta W. A. Kamil and J.M. Shreeve Inorg. Chem. 1985 24 2126. 101 T. Meier and R. Mews Angew. Chem. Int Ed. Engl. 1985 24 344. 102 M. Hargittai 0. V. Dorofeeva and J. Tremmel Inorg. Chem. 1985 24 3963; M. Hargittai 0. V. Dorofeeva and J. Tremmel Inorg. Chem. 1985 24 245. F CZ,Br I At and Noble Gases 191 with bond angles of ca. 110 "C and CoBr is linear. Theoretical investigations of the structure of MnC1 in the gas phase are consistent with it being linear.103 A new synthesis of /?-MoC12 has been described. The spectroscopic properties of this compound are consistent with it containing tetranuclear units in the Single crystals of NdC1 have been obtained by reaction of NdC1 with Li."' The corresponding reaction with K leads to KNd2Cl5. The vapour pressures at 600 K of NbC1 and NbBr4,lo6O the enthalpies of formation of NbBr and NbI4,lo6' and the sublimation pressures of NbBr, Nb15 and Ta15106c have been determined.OsBr can be obtained from OsCl and Br2 in a closed system. The structure contains OsBr octahedra connected by two common edges with a cis-arrangement of the non-bridging bromine atoms."' Spectroscopic evidence has been reported for the dimerization of TiC14 in argon matrices.lo8 The solid-state infrared and u.v.-visible spectra of CrF and CrF indicate fluorine-bridged poly- meric structure^.'^^ In low temperature matrices CrF and CrF are tetrahedral and octahedral respectively. The vaporization of CrF yields CrF and CrF by dispropor- tionation. Small amounts of NbCl and larger amounts of NbC1 are formed in the reaction of Nb3C18 with HCl at 500-600 oC.llo The reduction of VCl,(THF) with zinc in refluxing THF gives VC12.ZnC12.4THF.''' The crystal structure contains discrete molecules of (THF),V( p -C1),ZnC12 in which the coordination around V is approximately octahe- dral and around tetrahedral Zn.The octahedron and tetrahedron are linked by two chloride bridges. 14 Halogenometallates of the &Block Elements Nb61, reacts with a solution of MeNH to give a product of composition Nb,Ig( MeNH,),.1'2 The structural data are consistent with there being a 22-electron cluster system having the metal in the lowest oxidation state observed in niobium clusters. Aqueous solutions of [~a,Cl,~]~+ are reduced spontaneously to [~a,~l,,]~+ by concentrated HCl or HBr with the simultaneous oxidation of some cluster units to hydrated tantalum(v) oxide.' l3 CrF reacts with an excess of NF4HF2 to give the new stable salt NF4CrF6."4 It also reacts with FNO to give NO+CrF; and with H20 in HF hydrolysis occurs to give CrF,O.The compounds M(02PF2)2.HP02F2 (M = Mn Fe Co or Ni) Cr(02PF2)3.HP02F2,and two new forms of Fe(O2PF2) have been prepared and 103 M. Hargittai and A. R. Rossi Inorg. Chem. 1985 24 4758. 104 W. W. Beers and R. E. McCarIey Inorg. Chem. 1985 24 472. 105 G. Meyer and T. Schleid Z. Anorg. Allg. Chem. 1985 528 55. 1060 H. Schafer W. Loose and B. Monheim Z. Anorg. Allg. Chem. 1985 522 99. 106h B. Monheim and H. Schafer Z. Anorg. Allg. Chem. 1985 520 87. 106' H. Schafer B.Monheim and W. Loose 2.Anorg. Allg. Chem. 1985 522 108. 107 G. Thiele H. Wochner and H. Wagner Z. Anorg. Allg. Chem. 1985 530. 178. 108 E. Rytter and S. Kvistle Inorg. Chem. 1985 24 639. 109 E. G. Hope P. J. Jones W. Levason J. S. Ogden M. Tajik and J. W. Turf€ J. Chem. SOC.,Dalton Trans. 1985 1443. 110 H. Schafer and H. Lesaar Z. Anorg. Allg. Chem. 1985 523 187. Ill P. D. Smith J. L. Martin J. C. Huffman R. L. Bansemer and K. G. Caulton Inorg. Chem. 1985,24,2997. 112 F. Stollmaier and A. Simon Inorg. Chem. 1985 24 168. 113 J. Bricevic Z. Ruzic-Toros and B. Kojic-Prodic J. Chem. SOC.,Dalton Trans. 1985 455. I14 R. Bougon W. W. Wilson and K. 0. Christe Inorg. Chem. 1985 24 2286. M. J. K. Thomas characterized.' l5 All the compounds are polymeric with bidentate bridging difluorophosphate groups and octahedral environments for the metals.The [os2c18]2- anion can be prepared from 0~~(0~CMe)~Cl~ and HCl under anhydrous conditions.l16 The 0s-0s distance is very short and the anion may have a triply bonded diamagnetic ground-state. The reaction between [h-C16]- and BrF3 in liquid HF gives a mixture of [IrF,C16-,]-with n =14 from which the first chloride-containing Ir" compound Cs[ IrF,Cl] was isolated.' [IrCl Br6-,t]2- and [IrCl Br6-,,l3- can be separated by ion-exchange ~hromatography."'~ Treatment of [IrC&l3- with Br- gives nearly pure trans/ mer-isomers and reaction of [1rBr6l3-with C1-gives cislfuc-isomers for n =24 due to the stronger trans-effect of Br- compared with C1-.The structures of the following copper-containing anions have been determined and [CU~B~~]~-.~~~~ this year [CU~B~,]~-,"~~ Aqueous solutions of copper(1) iodide potassium iodide and crown ether form complexes having novel structures depending on the identity of the crown ether."' The structures of the HgBr and HgI ions have been determined. In MeNH3HgBr3 the Hg is in trigonal- bipyramidal coordination and the anion in the corresponding iodide complex is made up of corner-sharing chains of tetrahedra.120a In PPh4Hg13 however the unit cell contains a centrosymmetric [Hg2I6I2- anion (19).120b The structure of (NBu,)-I I I [Pt2Ag2C14(C6F5)4],first reported last year (see 1984 report) has been confirmed and the properties of this compound investigated.121 It reacts with PPh3 to give the new anionic compound (NBu,)[ PtAgC12(C6F5)2PPh3].15 Oxohalides Chalcogen-halides and Oxohalogenometallates of the &Block Elements A series of vanadium(v) oxide fluoride complexes have been characterized by "V and ''F n.m.r. spectroscopy.122 The niobium(1v) compounds Nb2X4S (X =C1 B,r) are formed by the reaction of NbX5 and Sb2S3 in CS2.123 They contain the [Nb-S-Nb-S2I4+ moiety and 115 M. F. A. Dove R. C. Hibbert and N. Logan J. Chem. SOC. Dalton Trans. 1985 707. 116 P. E. Fanwick M. K. King S. M. Tetrick and R. A. Walton J. Am. Chem. SOC. 1985 107 5009. 1176 W. Preetz and H.-J. Steinbach Z. Naturforsch. Teil. B 1985 40,745. 117b W.Preetz and H.-J. Steinbach Z. Naturforsch. B 1985 40,745.1180 S. Anderson and S. Jagner Acta Chem. Scand. Ser. A 1985 39 181; M. Asplund S. Jagner and M. Nilsson Acta Chem. Scand. Ser. A 1985 39 447. 1186 S. Anderson and S. Jagner Acta Chem. Scand. Ser. A 1985 39 423. 118c M. Asplund and S. Jagner Acta Chem. Scand. Ser. A 1985 39 47. 119 N. P. Rath and E. M. Holt J. Chem. SOC. Chem. Commun. 1985 665. 12Oa M. Korfer H. Fuess J. W. Bats and G. Klebe 2.Anorg. Allg. Chem. 1985 525 23. 1206 B. Zacharie J. D. Wuest M. J. Olivier and A. L. Beauchamp Acta Crystallogr. Sect. C 1985,41 369. 121 R. Uson J. Fornies B. Menjon F. A. Cotton L. R. Falvello and M. Tomas Inorg. Chem. 1985,24,4651. 122 R. C. Hibbert J. Chem. SOC. Chem. Commun. 1985 317. I23 M. G. B. Drew D. A. Rice and D. M. Williams J.Chem. SOC. Dalton Trans. 1985 417. F Cl Br I At and Noble Gases 193 form a range of adducts Nb2X4S3.nL (n = 4 L = NCMe SMe, or tetra-hydrothiophene; n = 2 L = PhSCH2CH2SPh). The complexes TcOCl, TcOClt- TcOBr, TcOBr:- and TcIi- have been charac- terized by EXAFS'240 and EPR.'24b The observed Tc=O and Tc-X bond lengths are consistent with the known dependence of bond length on coordination number the structural trans-effect of the Tc=O linkage and existing data on TcOCl and related moIybdenum species. WOCl can be prepared from tungstic acid in refluxing SOC~~.~~~ 16 Lanthanide Halides Anhydrous Ti Sc Y Er and Yb bromides can be prepared by the bromination of the corresponding hydrides.'26 The structural magnetic and electronic properties of EuX2 (X = C1 Br I) have been determined by "'Eu Mossbauer spectro~copy.'~~ The linear correlation observed between the isomer shift and the saturation hyperfine field indicates changing bonding ionicity.Covalency effects proceed mainly via charge transfer from the ligands' s or p orbitals to the empty Eu 6s orbital. The structure of Nd3Br5S2 is built up of Nd4S tetrahedra linked in ribbons and surrounded by Br atoms.'28 The Nd atoms in the middle of the ribbon are bonded to 4s and 4Br atoms and those at the edge to 2s and 5Br. The new compound Gd2NC13 is formed from GdCl and GdN or from GdC1 with N2 and Gd.'29 GdBr reacts with Cd and C to give Gd2C2Br Gd2CBr2 and Gd6C2Br7.13' 17 Actinide Halides The vaporization behaviour of U02F2in the range 900-1050 K shows that the total vapour pressure is made up of U02F2 and UFS 02,and solid U308formed by decomp~sition.'~~ Two additional processes give UF and UOF,.When F atoms are passed over U02 or U308the only products are UF and 02.13, Kinetic results indicate that the F atoms react immediately on contact with the surface and that both F2 molecules and F atoms react with the sample. Application of a pressure of 3.4GPa to the monoclinic form of CfBr gives the orthorhombic m~dification.'~~ 18 Graphite-Halide Intercalation Compounds and Graphite Fluorides The product of the reaction between graphite HS03F and F2 has an empirical formula C800,8F3,6.134 Treatment of this product with F2 gives CF1,23-1,25. The Raman infrared and n.m.r. spectra of graphite hydrofluorides C,F1-,( HF) (2 < 1240 R.W. Thomas M. J. Heeg R. C. Elder and E. Deutsch Inorg. Chem. 1985 24 1472. 1246 R. Kirmse J. Stach and U. Abram Inorg. Chem. 1985 24 2196. 125 R. H. Crabtree and G. G. Hlatky Polyhedron 1985 4 521. 126 A. I. Golovanova and A. I. Konstantinova Russ. J. Inorg. Chem (Engl. Trunsl.) 1985 30 320. 127 J. P. Sanchez J. M. Friedt H. Barnighausen and A. J. van Duyneveldt Inorg. Chem. 1985 24 408. 128 M. Julien-Pouzol S. Jaulmes P. Laruelle and C. Dagron Actu Crystullogr. Sect. C,1985 41 1286. 129 U. Schwanitz-Schuller and A. Simon 2.Nururforsch. Ted B 1985 40 705. 130 U. Schwanitz-Schuller and A. Simon Z. Naturforsch. TeilB 1985 40 710. 131 K. H. Lau R. D. Brittain and D. L. Hildenbrand J.Phys. Chem. 1985 89 4369. 132 W. H. Beattie and M. A. Salopek J. Fluorine Chem. 1985 30 59. 133 J. R. Peterson J. P. Young R. G. Haire G. M. Begun and U. Benedict Inorg. Chem. 1985 24,2466. 134 A. M. Danilenko A. S. Nazarov and 1. I. Yakovlev Russ. 1. Inorg. Chem. (Engl. Trunsl.) 1985,30 458. M. J. K. Thomas x < 5) have been obtained and peaks in the spectra assigned to graphitic and C-F ~arb0ns.l~~ The bonding of fluorine to carbon is highly ionic and the carbon atom sheets in these materials are very similar to those in graphite itself. Reaction of BrF with graphite followed by thermal treatment in a stream of inert gas gives a graphite compound of composition C26BrF12.1 (equation Graphite + BrF5(g) -. C,F(BrF,) + Br,(g) (10) Intercalation of SbC1,F into the graphite lattice is accompanied by dilation of the graphite crystals and a change of colo~r.'~' The compound is of stoicheiometry Clo,6SbC14F and the resistance of SbC1,F to hydrolysis is increased.Aqueous HCl ether ethanol acetic acid and acetonitrile extract part of the SbC1,F. Kinetic and isotherm data for the weight increase of some graphites in AsF vapour support the production of CsAsF5 followed by the post-intercalation conversion into C12ASFg and AsF3.13* Magnetic and structural properties of graphite compounds with MF6 (M = Re Tc) and previous data provide evidence for the existence of a correlation between the graphite layer spacing and the charge transfer of the he~aflu0rides.l~~ The layer spacing decreases with increasing charge transfer.This may be explained by a balance between coulombic attractive and elastic repulsive interactions. T. Maliouk B. L. Hawkins M. P. Conrad K. Zilm G. E. Maciel and N. Bartlett Philos. Trans. R. SOC. London Ser. A 1985 314 179. V. F. Sukhoverkhov Yu. I. Nikonorov and E. L. Zhuzhgov Russ. J. Inorg. Chern. (Engl. Trans/.) 1985 30,793. 137 H. Preiss Carbon 1985 23 595. 138 J. G. Hooiey Carbon 1985 23 579. 139 H. Selig D. Vaknin D. Davidov and Y. Yeshurun J. Chem. SOC.,Chem. Commun. 1985 1689.