Ammonium Thiomolybdates

By passing a current of hydrogen sulphide into an ammoniacal solution of (ordinary) ammonium molybdate, or by dissolving molybdenum trisulphide in ammonium sulphide solution, and concentrating by evaporating, blood-red crystals, appearing green by reflected light, of the normal salt (NH₄)₂MoS₄ are obtained. They are not completely stable in air. The compound NH₄MoS₆.H₂O has also been described.

By addition of a solution of ammonium hydrogen sulphide drop by drop to one of ammonium molybdate, the compound (NH₄)HMo₂S₃O₄ is precipitated as a reddish-yellow substance. Another mixed salt has the formula (NH₄O)₂MoS₂.