Symbol Mo. A silveryhard metallic transition element;a.n. 42; r.a.m. 95.94; r.d.10.22; m.p. 2617°C; b.p. 4612°C. It is found in molybdenite (MoS2), themetal being extracted by roasting togive the oxide, followed by reductionwith hydrogen. The element is usedin alloy steels. Molybdenum(IV) sulphide(MoS2) is used as a lubricant.Chemically, it is unreactive, beingunaffected by most acids. It oxidizesat high temperatures and can be dissolvedin molten alkali to give arange of molybdates and polymolybdates.Molybdenum was discoveredin 1778 by Karl Scheele.