Health, Safety & Environment
Molybdenum is widely distributed in nature. It is found in the minerals molybdenite,MoS2 which is the major ore of molybdenum, wulfenite, ferrimolybdate, jordisite, and powellite. Most molybdenum compounds are derived from molybdenum trioxide which is prepared by roasting molybdenum disulfide ores in air. Commonly used molybdenum-oxygen compounds are molybdenum trioxide, MoO3, sodium molybdate, Na2MoO4.2H2O, ammonium dimolybdate, (NH4)2 Mo2O7, and ammonium heptamolybdate, (NH4)6Mo7O24.4H2O.
Molybdenum is used mainly as an alloying element in steel, cast iron, and superalloys and in the electronics industries.
Leichtfried, G., in Ullmann's Encyclopedia of Industrial Chemistry ,5th ed. 1990, A16 , 668.
Molybdenum trioxide and molybdenum-oxygen compounds are added to steel and corrosion-resistant alloys. They are used in industrial catalysts, corrosion inhibitors, pigments, glass, ceramics, and enamels, flame retardant for polyester and polyvinyl chloride resins, as crop nutrients in agriculture, and as reagents in chemical analyses.
Vukasovich, M. S., in Ullmann's Encyclopedia of Industrial Chemistry ,5th ed., 1990, A16 , 682.
Molybdenum-sulfur compounds are used in lubrication to reduce friction and wear: molybdenum disulfide as a dry or suspended lubricant and molybdenum-sulfur complexes as soluble oil additives.
Mitchell, P. C. H., Wear , 1984, 100 , 281.
Other molybdenum compounds which find some application, for example, in the electronics industries and in chemical vapour deposition, are molybdenum pentachloride and molybdenum hexacarbonyl.
Environmental release of molybdenum compounds from industrial activities can occur in air (stack emissions), water (liquid effluents), or solid wastes (sludge): see Industrial and Environmental Exposure of Humans to Molybdenum.