Molybdenum forms three oxides and two sulphides. The oxides are MoO, MoO2 and MoO3, and the sulphides are MoS2 and Mo2S3. Molybdenum trioxide MoO3 is a pale yellow crystalline solid that melts around 800 degrees Celsius. Molybdenum dioxide melts at 1100 degrees Celsius . Molybdenum disulphide is a black crystalline solid that melts at about 1185 degrees Celsius. Actually, Molybdenum occurs in nature as the disulphide (MoS2) called molybdenite. It has the look and feel of graphite and is a semiconductor with energy gap of 1.8 electron volts. In 2011 it was demonstrated that it could be used as a transistor, with better voltage characteristics than silicon or graphene.
With selenium (Se), molybdenum forms molybdenum diselenide MoSe2 with two atoms of selenium. Molybdenum diselenide is a grey crystalline solid that melts above 2000 degrees Celsius. On decomposing, it gives out toxic fumes of selenium. Molybdenum ditelluride is also a grey crystalline solid. MoTe2, too, on decomposing produces poisonous fumes of tellurium that create breathing problems. Molybdenum diselenide and ditelluride are used in the superconducting thin film industry as sputtering materials with purity levels of 99.999 percent.
Molybdenum fluoride finds application in metal production where oxygen is not required.Trace amounts of the fluoride are incorporated in multi-mineral tablets because of their health benefits. Infact, the liver and kidney need traces of molybdenum to function properly. These come from certain foods such as legumes, peas, cereals and very green vegetables where molybdenum exists as the fluoride, chloride, bromide and iodide.
Molybdenum forms a compound with a carbon-oxygen complex called carbonyl (CO). The compound called molybdenum hexacarbonyl Mo(CO)6 is a white crystalline solid that melts and decomposes at 150 degrees Celsius. It is used as a catalyst that facilitates some chemical reactions involving synthesis.
Molybdenum disilicide, MoSi2, is highly refractory and used as a heating element for design of ovens and furnaces up to 1850 degrees Celsius or 3360 degrees Fahrenheit. It meets the needs of highly demanding environments and reducing atmospheres involving gases such as hydrogen, nitrogen and corrosive environments.