Nature 283, 751 - 752 (21 February 1980); doi:10.1038/283751a0

Why noble metals favour the face-centred cubic structure

C. S. G. Cousins

Physics Department, Exeter University, Exeter EX4 4QL, UK

The noble metals (copper, silver and gold) crystallise in the face-centred cubic (f.c.c.) structure but attempts to calculate their cohesive energy¹ and stacking fault energies² predict that the stable structure is the hexagonal close packed (h.c.p.). By considering a collinear three-ion interaction I have identified a source of energy, of the correct sign and order of magnitude, that explains the stability of the observed structure. Its success is largely due to a distinctive difference in number and spatial disposition of close-packed lines of atoms in the two structures. The principal parameters of the calculation are the scattering phase shifts of the ions and it is therefore highly probable that three-ion interactions also play a significant part in the stability of the transition metals.

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