AN ELECTRON SPIN RESONANCE STUDY OF S2O6F2-SO3F. EQUILIBRIUM . ENTHALPY OF CLEAVAGE

The fluorosulfate free radical (SO3F·, II) is produced by the homolytic thermal cleavage of neat liquid peroxydisulfuryl difluoride (S2O6F2, I), and its esr spectrum is investigated over the temperature range 4°  t  180°. The spectrum consists of a single structureless component with g = 2.0108 ± 0.0001 and a width which is unusually large and is temperature dependent [ΔHms ≍ 25 G (17°); ΔHms ≍ 48 G (180°)]. An analysis of measurements of the esr intensity as a function of temperature (125°  t  150°) leads to a determination of the enthalpy of thermal dissociation of I. The value obtained is 22.4 ± 0.9 kcal/mole. This result is in good agreement with values of the enthalpy change for this reaction in the gas phase which have been previously obtained using PVT and spectrophotometric techniques. © 1969, American Chemical Society. All rights reserved.