The Symmetry of the Benzene Molecule

Abstract
The melting points of various isomeric organic compounds indicate that molecular symmetry has an important effect on physical properties. With R. H. Fowler's statistical treatment of the crystal state, the symmetry number has been calculated for benzene and cyclohexene. The data employed are the vapor pressure, the heat capacity of the crystal, the heat capacity of the vapor as calculated from Raman spectra, the heat of sublimation and the moments of inertia. According to this calculation the symmetry number for benzene has the value 6±0.5 indicating that the molecule is not plane. The symmetry number for cyclohexene is 2±0.2 as is to be expected.