Crystal structure of trifluoro-oxosulphur(VI) hexafluoroarsenate(V), OSF3+AsF6–

Abstract

The crystal structure of the title compound has been determined from three-dimensional diffractometer data. Crystals are orthorhombic, unit cell dimensions: a= 10·88(1), b= 7·366(7), and c= 8·473(9)Å, Z= 4, space group Pnma. The atomic parameters were refined by block-diagonal least-squares to R 0·046 for 331 observed reflections. The structure consists of discrete OSF₃⁺and AsF₆^– ions. The OSF₃^– group is a distorted tetrahedron with bond lengths (corrected for liberation in parentheses) S–O 1·35(1)(1·37), S–F(5) 1·44(1)(1·45), and S–F(6) 1·45 (1)(1·46)Å; bond angles F(6)–S–O 116·3(6), F(5)–S–O 115·5(6), and F(5)–S–F(6) 102·0(5)°. The S–F bond length is the-shortest so far reported. The S–O bond length is also shorter than those determined previously, but is not significantly different from the axial S–O in S₃O₉. The structure of OSF₃⁺ is compared with those of some related species.