Calcium Molybdate, CaMoO₄

Mixed with calcium tungstate, Calcium Molybdate, CaMoO₄, occurs naturally as a greenish-yellow mineral, poxvellite, of density 5.35. Synthetic powellite has been prepared. By mixing solutions of neutral sodium molybdate and calcium chloride and boiling, or adding alcohol, a white precipitate is obtained. The composition of the strongly calcined product corresponds with that of the neutral salt. By fusing sodium molybdate with sodium and calcium chlorides, and then cooling, a mass of small tetragonal crystals of the salt is obtained.

Calcium molybdate is soluble in acetic acid. The introduction of molybdenum into steel can be satisfactorily effected by the use of calcium molybdate.

Tri-, tetra-, and octo-molybdates are known, and a double ammonium calcium paramolybdate.