Molybdenum

See also: Mo

The molybdenum is a chemical element, of symbol Mo and Atomic number 42.

History

The molybdenum (of the Greek molybdos , meaning “which resembles the Plomb”) does not exist in a native state, and its natural compounds were confused until the 18th century with compounds of other elements such as carbon or lead.

In 1778, Carl Wilhelm Scheele succeeds in separating molybdenum from the Graphite and lead, and isolates oxide from molybdenum of the Molybdénite.

In 1782, Peter Jacob Hjelm obtains an impure metal by reducing molybdenum oxide by carbon.

Until the end of the 19th century, molybdenum was only used very little apart from the laboratories. When the French steel manufacturer Schneider noticed the properties of alloys of steel molybdenum, it used them in the realization of shieldings.

Properties

Molybdenum is a Métal of transition. Pure metal is of metal white aspect and it is very hard.

Use

  • the addition of a small quantity of molybdenum hardens steel. More of two thirds of the production of molybdenum is used in alloys. The use of molybdenum climbed out of arrow during the First World War, when the request for the Tungstène made this one rare and that the alloys high strength were very required.
molybdenum is still used nowadays in alloys high strength and steels high temperature. Special alloys containing of molybdenum, like the Hastelloy ®, are resistant and do not corrode with high temperature.

  • molybdenum is used in certain parts of planes and missiles, and also like filament. One uses molybdenum like Catalyseur, particularly in oil industry, to eliminate the sulfur organic compounds from the Pétrole. It also returns in the composition of the Stainless steel used in the seamen circle, for its strong corrosion resistance chemical.

  • the 99Mo is a Radioisotope used in industry, as a precursor of the 99Tc.

  • molybdenum is used out of alloy like support of silicon for the realization of semiconductors of power, thanks to the dilation coefficients very close to these two materials.

  • the molybdenum oranges are pigments of the range of the orange means to orange red sharp, used in paintings, inks, the plastics and rubbers.

  • the disulfide of molybdenum is a lubricating good, particularly at high temperature.

  • molybdenum is usually used in laboratory like target in the tubes with x-rays for the Diffraction on Monocristal. The line K \ alpha of molybdenum has for average Wavelength 7,1073 Nm.

Molybdenum is an important component for the food of the plants and one finds it in certain enzymes like the xanthine oxydase.

Layers

Although one finds molybdenum in minerals such as the Wulfénite (Mo O 4 Pb) or the Powellite (Ca mn O4), the commercial independent source of molybdenum is the Molybdénite (Mo S 2).

Molybdenum is mined directly and is also a by-product of the mining of the Cuivre; the molybdenum concentration in this ore lies between 0,01 and 0,5%.

About half of the mining production of molybdenum comes from the the United States.

Simple: Molybdenum

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