The preparation and characterization of SeCl3SbF6, improved syntheses of MCl3(As/Sb)F6 (M = S, Se), and the X-ray crystal structure determination of SeCl3AsF6 and a new phase of SBr3SbF6

Alternative and, in some cases, improved syntheses of the salts MX 3 (As/Sb)F 6 (M = S, Se) and SCl 3 (SbCl 6 /AlCl 4 ) are described. In addition, the synthesis of SeCl 3 SbF 6 is reported. The compounds were characterized by FT-Raman spectroscopy and the X-ray crystal structures of SeCl 3 AsF 6 (also 77 Se NMR) and a new phase of SBr 3 SbF 6 were determined. Crystals of SeCl 3 AsF 6 and SBr 3 SbF 6 are monoclinic, space group P2 1 /c with [values for SBr 3 SbF 6 in brackets] a = 7.678(1) [8.137(1)] Å, b = 9.380(3) [9.583(2)] Å, c = 11.920(3) [12.447(2)] Å, β = 98.19(2)° [97.36(1)]°, V = 849.72(3) [962.6(3)] Å 3 ,z = 4, D x = 2.925 [3.502] Mg m −3 , R = 0.0525 [0.055], and R w = 0.0554 [0.060] for 1151 [1472] observed reflections. Key words: MX 3 + salts, FT-Raman spectroscopy, X-ray crystal structures of SeCl 3 AsF 6 , SBr 3 SbF 6 , and preparation of SeCl 3 SbF 6 .