Hexaammonium molybdate

Chemical properties

Ammonium heptamolybdate is an odourless crystalline compound ranging in colour from white to yellow-green. It is usually encoutered as the tetrahydrate, whose chemical formula is (NH4)6Mo7O24·4H2O. It is often referred to simply as ammonium molybdate, although this name can also refer to ammonium orthomolybdate, (NH4)2MoO4, and several other species.

General Description

White to greenish-yellow solid. Sinks and mixes with water.

Air & Water Reactions

Water soluble.

Reactivity Profile

Salts, basic, such as Hexaammonium molybdate , are generally soluble in water. The resulting solutions contain moderate concentrations of hydroxide ions and have pH's greater than 7.0. They react as bases to neutralize acids. These neutralizations generate heat, but less or far less than is generated by neutralization of the bases in reactivity group 10 (Bases) and the neutralization of amines. They usually do not react as either oxidizing agents or reducing agents but such behavior is not impossible.

Health Hazard

Inhalation causes irritation of nose and throat. Contact with eyes causes irritation.

Fire Hazard

Special Hazards of Combustion Products: Toxic oxides of nitrogen may form in fire.

Flammability and Explosibility

Not classified

Agricultural Uses

Ammonium molybdate, (NH₄)₆MO₇O₂₄·2H₂O is an important molybdenum fertilizer. It is an ammonium salt of molybdic acid and contains about 50% molybdenum.
Ammonium molybdate is generally mixed with NPK fertilizers, depending on the crop requirement (generally 50 to l000 gm per ha). The fertilizer is also applied as a foliar spray, but coating or soaking seeds with ammonium molybdate is the easiest method of application, which requires very little fertilizer.

Safety Profile

Mutation data reported. Whenheated to decomposition it emits toxic vapors of Mo andNH3.