Barium Tetramolybdate, BaMo₄O₁₃.5H₂O

Barium Tetramolybdate, Barium Metamolybdate, BaMo₄O₁₃.5H₂O or Ba₃H₄[H₂(Mo₂O₇)₆].12H₂O, is precipitated when a solution containing barium chloride and sodium octamolybdate is warmed, or when barium octamolybdate is treated with hot water. On heating to 120° C. the compound loses four-fifths of the water present, which corresponds to the 12H₂O in the above constitutional formula. The addition of barium chloride to a solution of sodium tetramolybdate yields the hydrate 2BaMo₄O₁₃.7H₂O.