Molybdenum

Molybdenum is a Group 6 chemical element with the symbol Mo and atomic number 42. The name is from Neo-Latin Molybdaenum, from Ancient Greek Μόλυβδος molybdos, meaning lead, since its ores were confused with lead ores. Molybdenum minerals have been known into prehistory, but the element was "discovered" (in the sense of differentiating it as a new entity from the mineral salts of other metals) in 1778 by Carl Wilhelm Scheele. The metal was first isolated in 1781 by Peter Jacob Hjelm.

Molybdenum does not occur naturally as a free metal on Earth, but rather in various oxidation states in minerals. The free element, which is a silvery metal with a gray cast, has the sixth-highest melting point of any element. It readily forms hard, stable carbides in alloys, and for this reason most of world production of the element (about 80%) is in making many types of steel alloys, including high strength alloys and superalloys.

Most molybdenum compounds have low solubility in water, but the molybdate ion MoO42− is soluble and forms when molybdenum-containing minerals are in contact with oxygen and water. Industrially, molybdenum compounds (about 14% of world production of the element) are used in high-pressure and high-temperature applications, as pigments and catalysts.

Molybdenum-containing enzymes are by far the most common catalysts used by some bacteria to break the chemical bond in atmospheric molecular nitrogen, allowing biological nitrogen fixation. At least 50 molybdenum-containing enzymes are now known in bacteria and animals, although only bacterial and cyanobacterial enzymes are involved in nitrogen fixation, and these nitrogenases contain molybdenum in a different form from the rest. Owing to the diverse functions of the various other types of molybdenum enzymes, molybdenum is a required element for life in all higher organisms (eukaryotes), though not in all bacteria.

Read more about MolybdenumHistory, Occurrence, Production of The Metal, Precautions

Other articles related to "molybdenum":

Molybdenum - Precautions
... Molybdenum dusts and fumes, which can be generated by mining or metalworking, can be toxic, especially if ingested (including dust trapped in the sinuses and later swallowed) ... Direct inhalation or ingestion of molybdenum and its oxides should be avoided ... OSHA regulations specify the maximum permissible molybdenum exposure in an 8-hour day as 5 mg/m3 ...
Climax Mine - Geology
... ore deposits, the ore is low-grade, much less than one percent molybdenum, but the ore bodies are very large ... Beside molybdenum, the mine has also produced tin (from cassiterite), tungsten (from hübnerite), and pyrite as by-products ... The Climax deposit is one of a number of large molybdenum deposits in central Colorado and northern New Mexico ...
Molybdenum Chloride
... Molybdenum chloride can refer to Molybdenum(II) chloride (molybdenum dichloride), MoCl2 Molybdenum(III) chloride (molybdenum trichloride), MoCl3 Molybdenum(IV) chloride (molybdenum ...
Isopoly Molybdenum Blues
... The isopoly-molybdenum blues have been known for many years ... Molybdenum(VI)oxide, MoO3, when dissolved in aqueous alkali forms the tetrahedral molybdate anion, MoO42− ... The later unit occurs also in the giant mixed-valence molybdenum blue species 48− (x≈16) as well as in the cluster described in the next section ...
Climax Mine - History
... Senter discovered and claimed the outcropping of molybdenite (molybdenum sulfide) veins in 1879, during the Leadville, Colorado, Silver Boom, but he had no ... finally found a chemist who identified the gray mineral as containing molybdenum in 1895, at the time there was virtually no market for the metal ... When steelmakers found the usefulness of molybdenum as an alloy in producing very hard steel, the first ore shipments from the deposit began in 1915, and the Climax mine began full production in 1914 ...