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molybdenum 音标拼音: [məl'ɪbdɪnəm] n. 钼 钼 molybdenum 钼 MO molybdenum 钼 molybdenum n 1: a polyvalent metallic element that resembles chromium and tungsten in its properties; used to strengthen and harden steel [synonym: {molybdenum}, {Mo}, {atomic number 42}] Molybdenum \Mol`yb*de"num\, n. [NL.: cf. F. molybd[`e]ne. See {Molybdena}.] (Chem.) A rare element of the chromium group, occurring in nature in the minerals molybdenite and wulfenite, and when reduced obtained as a hard, silver-white, difficulty fusible metal. Symbol Mo. Atomic number 42. Atomic weight 95.94. [1913 Webster PJC] molybdenum
Symbol: Mo Atomic number: 42 Atomic weight: 95.94 Silvery-white, hard metallic transition element. It is chemically unreactive and is not affected by most acids. It oxidizes at high temperatures. There are seven natural isotopes, and four radioisotopes, Mo-93 being the most stable with a half-life of 3500 years. Molybdenum is used in almost all high-strength steels, it has nuclear applications, and is a catalyst in petroleum refining. Discovered in 1778 by Carl Welhelm Scheele of Sweden. Impure metal was prepared in 1782 by Peter Jacob Hjelm. The name comes from the Greek word molybdos which means lead. Trace amounts of molybdenum are required for all known forms of life. All molybdenum compounds should be considered highly toxic, and will also cause severe birth defects.
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