Physical Properties of Actinide Metals up to Pu

The physical properties of actinide metals up to Pu - including the magnetic properties-are all governed by the complicated 5f-6d-7s conduction band. 

A pioneering work for their qualitative understanding was the covalent treatment of the 5f-6d hybridization due to FriedeP Like p orbitals, f orbital are antisymmetric (il)(— R) = — tl)(R)) thus by linear combination with symmetric d orbitals, they give rise to highly directive hybrid orbitals (like s-p hybrids). Thus in Pa, U, Np and Pu metals each atom has four nearest neighbours more or less coplanar and at 90°. Let s take the example of a-U and put the nearest neighbours along the x and z axes. Necessary hybrid orbitals for such positions are  

It allows also to explain, from covalency effects, the anisotropy of transport properties  

Detailed comparison between band structure calculations and experiments has been possible only for Th and to a less extent a-U. It is doubtful that such a level of sophistication will be reached for the low temperature, low symmetry, phases of Np and Pu metals. 

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