Crystal structure of rubidium fluoroxysulfate. Characterization of the fluoroxysulfate anion

The rubidium salt of the recently identified fluoroxysulfate anion, FOSO/sub 3//sup -/, has been characterized by single-crystal X-ray diffraction. RbFOSO/sub 3/ crystallizes in the centrosymmetric triclinic space group, Pl, with unit cell constants a = 5.503 (2) A, b = 5.623 (1) A, c = 7.603 (3) A, ..cap alpha.. = 100.64 (2)/sup 0/, ..beta.. = 106.72 (2)/sup 0/, ..gamma.. = 93.22 (2)/sup 0/, and Z = 2. The X-ray data refine to an R/sub F/ = 0.067 for 664 reflections with F/sup 2/ > sigmaF/sup 2/. The fluoroxysulfate anion has distorted tetrahedral coordination with each central sulfur atom bound to four oxygens. The S-O bond distances are 1.435 (8), 1.426 (8), 1.441 (7), and 1.652 (9) A. The O-F bond distance is 1.412 (10) A, and the S-O-F bond angle is 107.8 (6)/sup 0/. Each Rb/sup +/ cation is coordinated to nine oxygen atoms and two fluorine atoms.