Covalency in cubic lanthanide sesquioxides

Abstract

The overlap integrals (2s mod 4f), (2p sigma mod 4f), and (2p pi mod 4f) have been calculated for the entire series of cubic lanthanide sesquioxides (C-Ln 2 O 3 ) through analytical five-term (2s, 2p: O 2- ) and four-term (4f:Ln 3+ ) ground-state wavefunctions. The set of distances used for C 2 and C 3i cation sites is reported for the first time. It has been found that only pi -type electron delocalisation is feasible within the fragment Ln 3+ -O 2- ; the respective overlap integrals vary from 0.12 to 0.03.