Abstract
The wide variations in lubricating properties among candidate solid lubricants with similar crystal structures are explained in terms of the distribution of valence electrons in the various materials. The electron distribution is inferred from a simplified chemical bonding scheme which is based on interactions between atomic orbitals and on the structural parameters of the materials. Comparisons in structure and properties are made between graphite and boron nitride, and between the disulfides and diselenides of niobium, molybdenum, tantalum, tungsten and rhenium.