The anisotropy of the Cl₂−Cl₂ pair potential as shown by the crystal structure Evidence for intermolecular bonding or lone pair effects?

Abstract

The intermolecular forces which determine the structure of crystalline chlorine were investigated using a variety of anisotropic interrnolecular potentials. The electrostatic interaction was represented by a set of distributed multipoles calculated from an ab initio wavefunction.

It was not found necessary to invoke the existence of intermolecular bonding in solid Cl₂; excellent structural predictions, with r.m.s, errors in the lattice parameters of better than 0.1 per cent, could be obtained with suitable models for the anisotropy of the repulsion forces. For an atomatom potential, the required anisotropic form can be interpreted as modelling the lone pairs on Cl₂.