ESR study on the structure of the ethylene radical cation stabilized in frozen SF6 and some fluoroalkanes: An evidence for a twisted structure

ESR spectra of the ethylene radical cation were detected at cryogenic temperatures in SF₆, C₂F₆ and C₃F₈. From the unusually small hyperfine couplings estimated for¹H and¹³C, it has been shown that the ethylene radical cation has a non-planar structure with a torsional angle in the range of 8°–23°. Upon annealing the sample at a temperature above 93 K, the ethylene radical cation in SF₆ changed into a monofluoroethyl radical through charge recombination with fluoride anion or SF ₆ ^? .