ANTIMONY(III) FLUORIDE FLUOROSULFATES - SYNTHESES AND MOLECULAR-STRUCTURES OF ANTIMONY(III) DIFLUORIDE FLUOROSULFATE [SBF2(SO3F)](X), ANTIMONY(III) FLUORIDE BIS(FLUOROSULFATE) [SBF(SO3F)(2)](X), AND ANTIMONY(III) TRIS(FLUOROSULFATE) [SB(SO3F)(3)](X)

Following unsuccessful attempts to confirm the existence of previously reported antimony(I) fluorosulfate, Sb(SO3F), the reaction of antimon y and fluorosulfuric acid is reinvestigated and synthetic routes are d eveloped that allow the preparation of polymeric [SbF2(SO3F)](x), [SbF (SO3F)(2)](x), and [Sb(SO3F)(3)](x). Recrystallization from fluorosulf uric acid is found to produce single crystals of all three materials, which are suitable for molecular structure determinations by single-cr ystal X-ray diffraction. Crystals of [SbF2(SO3F)](x) are orthorhombic, a = 13.4035(6) Angstrom, b = 7.1852(6) Angstrom, c = 5.0239(9) Angstr om, Z = 4, and space group Pna2(1). Crystals of [SbF(SO3F2)](x) are mo noclinic, a = 10.7302(8) Angstrom, b = 4.899(1) Angstrom, c = 13.671(1 ) Angstrom, b = 111.253(7)degrees, Z = 4, space group P2(1)/c. Crystal s of [Sb(SO3F)(3)](x) are hexagonal, a = 9.5718(9) Angstrom, c = 17.28 3(1) Angstrom, Z = 6, and space group P6(5). Data for all three compou nds were collected to high resolution (Mo radiation, 2 theta(max) = 10 0 degrees) in order to provide accurate structural information. The st ructures were solved by Patterson ([SbF2(SO3F)](x) and [SbF(SO3F)(2)]( x)) or direct methods ([Sb(SO3F)(3)](x)) and were refined by full-matr ix least-squares procedures to R = 0.025, 0.028, and 0.030 (R(W) = 0.0 26, 0.027, and 0.027) for 1807, 4572, and 2675 reflections with I grea ter than or equal to 3 sigma(F-2), respectively. The three structures, together with the previously reported structure of [SbF3](x), allow a detailed comparison for all four members of the series [SbFn(SO3F)(3- n)] for n = 0, 1, 2, or 3. In all structures, fluorines function as as ymmetrical, bidentate bridges between two different antimony atoms, wh ile the fluorosulfates are found to form asymmetric O-tridentate bridg es. Hence the coordination number for antimony increases from 6 for [S bF3](x) to 7 for [SbF2(SO3F)](x), 8 for [SbF(SO3F)(2)](x), and 9 for [ Sb(SO3F)(3)](x). All coordination geometries are highly distorted. Acc ording to Sb-O or Sb-F bond distances, the bonds are classified as pri mary (similar to 2.0 +/- 0.1 Angstrom), intermediate (similar to 2.5 /- 0.1 Angstrom), and secondary (similar to 2.9 +/- 0.1 Angstrom). The primary coordination geometries are trigonal pyramidal for SbF3, [SbF (SO3F)(2)](x), and [Sb(SO3F)(3)](x), and distorted square pyramidal fo r [SbF2(SO3F)](x).