A 19F nuclear magnetic resonance investigation of the formation of Sb2F11− and SbnF5n+1− in the CsF–SbF5, t-butyl halide–SbF5, and tetraalkylammonium hexafluoroantimonate–SbF5 systems

Fluorine nuclear magnetic resonance spectra have been obtained for the t-butyl fluoride–SbF5, t-butyl chloride–SbF5, tetraethylammonium hexafluoroantimonate–SbF5, and cesium fluoride–SbF5 systems, both with and without SO2 solvent. In SO2 solution the anion is Sb2F11− for all the systems, any remaining SbF5 being converted to SbF5•SO2. It is concluded that in the systems that do not contain SO2, higher polymeric anions SbnF5n+1−, where n > 2, are present. t-Butyl chloride and t-butyl fluoride give the t-butyl carbonium ion, as has been previously reported. Tetrabutylammonium and benzyltri-methylammonium cations appear to decompose to a carbonium ion and an adduct SbF5•NR3 in the presence of SbF5.