haf·ni·um /ˈhæfniəm/
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haf·ni·um /ˈhæfnɪəm/ 名詞
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haf·ni·um n. A metallic element of atomic number 72 present together with zirconium to the extent of 1% to 5% in zirconium minerals. It is a poisonous, ductile metal with a brilliant silver luster, has an atomic weight of 178.49, and has a high melting point (2227° C). It is used in nuclear reactors, and incandescent lamps as a scavenger of oxygen and nitrogen. See also norium.
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hafnium
n : a gray tetravalent metallic element that resembles zirconium
chemically and is found in zirconium minerals; used in
filaments for its ready emission of electrons [syn: Hf,
atomic number 72]
hafnium
Symbol: Hf
Atomic number: 72
Atomic weight: 178.49
Silvery lustrous metallic transition element. Used in tungsten alloys in
filaments and electrodes, also acts as a neutron absorber. First reported
by Urbain in 1911, existence was finally established in 1923 by D. Coster,
G.C. de Hevesy in 1923.