Molybdenum
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Molybdenum is a Group 6 chemical element wi the seembol Mo an atomic nummer 42. The name is frae Neo-Laitin Molybdaenum, frae Auncient Greek Μόλυβδος molybdos, meanin leid, syne its ores wur confused wi leid ores.[5] Molybdenum meenerals hae been kent intae prehistory, but the element wis discovered (in the sense o differentiatin it as a new entity frae the mineral sauts o ither metals) in 1778 bi Carl Wilhelm Scheele. The metal wis first isolatit in 1781 bi Peter Jacob Hjelm.
Molybdenum disnae occur naiturally as a free metal on Yird, but rather in sindry oxidation states in meenerals. The free element, whilk is a sillery metal wi a gray cast, haes the saxt-heichest meltin pynt o ony element. It readily furms haird, stable carbides in alloys, an for this raison maist o warld production o the element (aboot 80%) is in makin mony types o steel alloys, includin heich strength alloys an superalloys.
Maist molybdenum compounds hae law solubility in watter, but the molybdate ion MoO2−
4 is soluble an furms whan molybdenum-containin meenerals are in contact wi oxygen an watter. Industrially, molybdenum compoonds (aboot 14% o warld production o the element) are uised in high-pressure an heich-temperatur applications, as pigments an catalysts.
Molybdenum-containin enzymes is bi far the maist common catalysts uised bi some bacteria tae break the chemical bond in atmospheric molecular nitrogen, allaein biological nitrogen fixation. At least 50 molybdenum-containin enzymes are nou kent in bacteria an ainimals, tho anly bacterial an cyanobacterial enzymes is involved in nitrogen fixation, an thirnitrogenases contain molybdenum in a different furm frae the rest. Awin tae the diverse functions o the sindry ither types o molybdenum enzymes, molybdenum is a required element for life in aw heicher organisms (eukaryotes), tho nae in aw bacteria.
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