Understanding metal bonding.

This theoretical discussion covers several effects of metallic bonding based on a simple formula. It comes from the first steps in the Moment Method for calculating the local electronic structure of a solid (such as at a surface or in a random alloy), and depends on the square root of the total coordination numberCof near neighbours. Each atom is covalently bonded to its cluster of near neighboursas a whole. The properties of metals touched on include malleability, crystal structure and phase transitions, vacancy formation energy, surface catalysis, surface reconstruction, graphite stability, and some aspects of the benzene molecule seen as an atomic metal ring. In most of these, the 'saturation' type of curvature of the square root function plays a crucial role. A short historical survey indicates the development of the ideas from Bloch (1929Z. Phys.52555) to recent times.