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Molybdenum - Dictionary Definition and Overview |
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Molybdenum : (noun)
1: a polyvalent metallic element that resembles chromium and
tungsten in its properties; used to strengthen and harden
steel [syn: Mo, atomic number 42]
Based on WordNet 2.0
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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 weight 95.9.
Based on Webster's Revised Unabridged Dictionary
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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.
Based on Webster's Revised Unabridged Dictionary (1913)
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