Acta Crystallographica Section B

Structural Science

Volume 53, Part 4 (August 1997)

research papers

Acta Cryst. (1997). B53, 613-619 [ doi:10.1107/S0108768197004102 ]

Pentachlorotoluene: Rotational and Compositional Disorder

C. P. Brock and Y. Fu

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 ( < $\psi$ ²> = 13 deg²); the barrier to in-plane rotation is estimated as 35 (3) kJ mol^-1. Compositional disorder is a possibility.