Hafnium

3 definitions found

From The Collaborative International Dictionary of English v.0.48 [gcide]:

  hafnium \haf"ni*um\ (h[a^]f"n[=e]*[u^]m or h[aum]f"n[=e]*[u^]m),
     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[deg] C). It is used in nuclear reactors, and
     incandescent lamps as a scavenger of oxygen and nitrogen. See
     also {norium}.
     [1913 Webster]

From WordNet (r) 2.0 [wn]:

  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}]

From Elements database 20001107 [elements]:

  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.