A spectroscopic investigation of cerium molybdenum oxides

Abstract

A detailed X-ray photoelectron, i.r., and Raman spectral study has been made of Ce₂(MoO₄)₃ and five novel cerium molybdenum oxides (α- and β-Ce₂Mo₄O₁₅, β- and γ-Ce₂Mo₃O₁₃, and Ce₈Mo₁₂O₄₉), which are of particular interest as they are closely related to the cerium molybdenum oxide species which are expected to play an active role in an industrial cerium molybdenum tellurium oxide acrylonitrile catalyst. The photoemission results add to the few existing previous data concerning cerium compounds and confirm the valence distribution in the compounds. With the exception of the tetrahedral oxomolybdenum co-ordination in Ce₂(MoO₄)₃ the cerium molybdates consist of highly irregular or mixed polyhedral arrangements with Mo–O bond strengths (in valence units) either below 0.3 v.u or above 1.0 v.u.