The Preparation and Colors of Alkaline Earth Metal Cerium Molybdenum Oxides as Yellow Pigment

Abstract

M_II^0.5CeMo₂O₈ (M : alkaline earth metal) was prepared by a solid-state reaction for the improvement of chemical resistance of LiCeMo₂O₈. As a result, Ca_0.5CeMo₂O₈ was prepared by heating at 900°C, which had the most vividly yellow hue among the products. The absorption edge of spectral reflectance curve of Ca_0.5CeMo₂O₈ shifted to shorter wavelength by substitution of Sr²⁺ ion or W⁶⁺ ion. It was considered that the change of electronegativity gave a big influence to the absorption edge of spectral reflectance curve of Ca_0.5CeMo₂O₈, because of the yellow hue of Ce³⁺ ion based on 4f-5d transition. It is obvious that its chemical resistance was improved greatly by substitution of Ca²⁺ ion compared with LiCeMo₂O₈. Especially, Ca_0.5CeMo₂O₈ had good resistance equal to cadmium yellow and bismuth vanadate in alkali solution.