Ring inversion in solid fluorocyclohexane

Inversion of the cyclohexane ring system in the solid state has been directly observed in a 19F nmr study of solid fluorocyclohexane. The barrier to ring inversion in the orientationally disordered solid phase, ΔG≠e→a = 44.1 ± 0.9 kJ mol−1 at 263 K is found to be only slightly larger than the value previously reported for a CFCl3 solution of fluorocyclohexane. The population of the equatorial conformation is slightly favored over the axial conformation with K = Pe/Pa = 1.56 at 281 K; similar values have been obtained in CFCl3 and in the gas phase.