A quantum description of the chemical bond

Abstract

Traditionally a molecule's structure and properties are seen as originating from its bonds, despite the fact that there is no rigorous quantum mechanical description of a bond. Here, the formalism of atoms in molecules is extended and the chemical bond is rigorously defined. Using this definition, it is possible to associate properties unambiguously with particular bonds, with its energy being one such property. With this definition for a bond, it is demonstrated that there are relationships between the bonding and the solid-state properties of a series of transition-metal aluminides. It is shown that these relationships correlate well with the computed difference between first- and second-neighbour bond energies. It is argued that the resulting bonding-property relationships provide the conceptual basis from which to alter bonds predictably and systematically and the properties that originate from these.