Preparation and X-ray crystal structure of caesium imidodisulphuryl fluoride Cs[N(SO2F)(2)]

The salt Cs[N(SO2F)(2)] was prepared from a stoichiometric reaction of imidodisulphuryl fluoride, HN(SO2F)(2), and caesium hydroxide in high yield. The crystal structure of Cs[N(SO2F)(2)] was determined at room temperature. The compound is monoclinic, space group P2(1)/n, with four molecules in a unit cell of dimensions a = 7.884 0(3) Angstrom, b = 8.455 0(5) Angstrom, c = 10.659 0(5) Angstrom, and beta = 99.621(4)degrees with R = 0.024, R(w)(2) = 0.066, for 1234 observed [I > 2 sigma (I)] reflections (for all data: R = 0.025, R(w)(2) = 0.074). The nitrogen atom in the anionic moiety [N(SO2F)(2)](-) has trigonal planar coordination geometry with an S-N-S angle of 120.8(2)degrees.