Relating the energy of the †Xe‡5d configuration of Ce in inorganic compounds with anion polarizability and cation electronegativity

Recently, the energy of all five levels of the @Xe#5d configuration of Ce in 63 different fluorides and oxides have become available. It provides values for the barycenter shift of the 5d configuration. This shift was analyzed by a model that involves the polarizability of the anion ligands, and values for the in-crystal anion polarizability were obtained. In this work, for Ce in both the oxides and the fluorides, a linear relationship between the anion polarizability and the inverse square of the average electronegativity of the cations in the compounds is demonstrated. With few parameters, the magnitude of the nephelauxetic effect in inorganic compounds can now be predicted. More importantly, insights are provided on the relationship between physical and chemical properties of compounds and the luminescent properties of lanthanides.