Calcium Tetramolybdate, CaMo₄O₁₃

Calcium Tetramolybdate has not been obtained in the crystalline condition. It remains as a vitreous mass, of composition CaMo₄O₁₃.9H₂O, when the liquid, obtained after boiling an aqueous suspension of calcium carbonate with molybdic acid and filtering, is evaporated rapidly to dryness; if the solution is allowed to stand the trimolybdate is formed.