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.