CaMoO

Calcium molybdate, commonly referred to as CaMoO4, is an inorganic compound that forms as a white, crystalline solid. The shorthand CaMoO is sometimes found in older literature, but the accepted chemical formula is CaMoO4. It is primarily known for its role as a pigment and as a host lattice for luminescent materials.

CaMoO4 crystallizes in the scheelite-type tetragonal structure and is isostructural with calcium tungstate (CaWO4). It is relatively chemically stable and has low solubility in water, making it suitable for use in coatings. The compound can be synthesized and processed through several routes, including high-temperature solid-state reaction of calcium carbonate (CaCO3) with molybdenum trioxide (MoO3) at elevated temperatures, typically around 800–1000°C, with evolution of carbon dioxide. It can also be prepared by precipitation from aqueous solutions containing calcium ions and molybdate ions, followed by drying and calcination to achieve crystallinity.

In addition to its use as a corrosion-inhibiting pigment in paints and coatings, CaMoO4 serves as a host lattice for luminescent dopants. When doped with rare-earth or transition-metal ions, it can form phosphors and, in some cases, scintillating materials for optical and display applications.

Safety and handling considerations are similar to other inorganic oxides: CaMoO4 is generally of low to moderate toxicity, with potential irritation if dust is inhaled or ingested. Standard laboratory hygiene and protective equipment should be used when handling powders, and proper disposal according to local regulations is advised.

See also: Calcium tungstate, Molybdate pigments, CaWO4.