The cerium peculiar valence charge in CeN

Rare earth nitrides are very interesting due to a well-behaved ionic radii-dependent physical observables. However, cerium nitride is different in many ways, for example, its lattice parameter does not “match” with Ce ionic radius in comparison with other rare-earth nitrides. To contribute to this issue, here I propose three models, based on very accurate classical calculations, which take into account charge transfers and/or contamination by Ce4+ ions to describe valence states in cerium nitride compounds from T=0 K to T>1500 K. This thermal dependence of the Ce valence charge has permitted to calculate many temperature-dependent physical observables. Such information is useful to clarify the Ce valence state in cerium nitride as well as give some estimations concerning experimental data in a very large temperature range of cerium nitride compounds.