An investigation of the structures of the adducts of SF4 with BF3, PF5, AsF5, and SbF5 in the solid state and in solution in HF

The structure of the solid adducts of SF 4 with several fluoride acceptors has been studied by investigations of the 18 F exchange between S 18 F 4 and BF 3 and between SF 4 and B 18 F 4 , the infrared spectrum of SF 4 .BF 3 , and the Raman spectra of SF 4 .BF 3 , SF 4 .PF 5 , SF 4 .AsF 5 , and SF 4 .SbF 5 . The experimental observations are best accounted for in terms of an ionic structure SF 3 + .MX n − in each case, but there is good evidence for relatively strong fluorine bridging between the ions.In anhydrous hydrogen fluoride solution, SF 4 and the adducts SF 4 .BF 3 and SF 4 .SbF 5 were studied conductimetrically and by 19 F nuclear magnetic resonance. Both methods indicate complete ionization of the adducts to SF 3 + and the complex fluoroanion. SF 4 is a weak base in hydrogen fluoride ionizing to SF 3 + and HF 2 − .