(±)-3-Formyl-1-methyl-2-(2-phenylethyl)cyclohex-2-enecarboxylic Acid: an Investigation of Disorder

The structure of the title compound, C 17 H 20 O 3 , a substituted cyclohexene system, has been determined. The high degree of disorder in various substituent moieties results in two different orientations of the molecule in the crystal lattice which have unequal occupancy factors. Lattice-energy calculations based on van der Waals attractive and repulsive potentials clearly show minima at the observed disordered positions. The difference in occupancy factors between the two molecular orientations can be explained from the relative values of lattice energies.