Elastic-constant systematics in f.c.c. metals, including lanthanides-actinides

For f.c.c. metals, using Blackman's diagram of dimensionless elastic‐constant ratios, we consider the systematics of physical properties and interatomic bonding. We focus especially on the lanthanides–actinides La, Ce, Yb, Th, U, Pu, those for which we know some monocrystal elastic constants. Their behavior differs from the other f.c.c. metals, and all except La show a negative Cauchy pressure, contrary to most f.c.c. metals, which show a positive Cauchy pressure. Among the lanthanides–actinides, δ‐Pu stands apart, consistent with its many odd physical properties. Based on elastic‐constant correlations, we suggest that δ‐Pu possesses a strong s‐electron interatomic‐bonding component together with a covalent component. Elastically, δ‐Pu shows properties similar to Yb. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)