The core levels and the valence-band region of CeN have been studied by x-ray photoemission. Clear evidence is found that Ce has a mixed valence between 3 and 4 in this compound. A comparison of the $4d$ spectra of the Ce pnictides and of pure Ce at different temperatures leads to the conclusion that the $\alpha$ phase of this metal corresponds very likely to an intermediate valence.

• Received 25 July 1977

DOI:https://doi.org/10.1103/PhysRevLett.39.956