Pentachlorotoluene: Rotational and Compositional Disorder

Abstract

The structure of pentachlorotoluene, which is isostructural with most other C6Cl n (CH3)_{6-n} derivatives, has been redetermined at 294 (1) K. The methyl group is distributed almost randomly among six sites; there is little discrimination between the Cl and CH3 substituents. The TL thermal-motion description suggests that the in-plane libration is moderate ( <\psi2> = 13 deg2); the barrier to in-plane rotation is estimated as 35 (3) kJ mol−1. Compositional disorder is a possibility.