HYBRIDIZATION EFFECTS IN SOME UX5 COMPOUNDS

The presence of the magnetic moments on the uranium atoms in some of the UX5-xYx compounds (X and Y are 3d, 4d or 5d transition element) is discussed using the hybridization strength of the s, p, d and f atomic orbitals. By using a semi quantitative band structure approach due to Straub and Harrison, the hybridization effects in these binary and ternary series of isostructural compounds were evaluated. Comparing the bandwidth with a theoretical critical energy (for f(2) and f(3)) in order to predict if the ground state is magnetically ordered it seems that f(3) is not the exact electronic configuration for uranium in this class. This fact is correlated with the suggestion that the U valence in the UCu5 group is a mixture of values where the tetravalent component (f(2) configuration) is a significant one.