Tantalum

3 definitions found

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

  Tantalum \Tan"ta*lum\, n. [NL. So named on account of the
     perplexity and difficulty encounterd by its discoverer
     (Ekeberg) in isolating it. See {Tantalus}.] (Chem.)
     A rare nonmetallic element found in certain minerals, as
     tantalite, samarskite, and fergusonite, and isolated as a
     dark powder which becomes steel-gray by burnishing. Symbol


     Ta. Atomic weight 182.0. Formerly called also {tantalium}.
     [1913 Webster]

From WordNet (r) 2.0 [wn]:

  tantalum
       n : a hard gray lustrous metallic element that is highly
           corrosion-resistant; occurs in niobite and fergusonite
           and tantalite [syn: {Ta}, {atomic number 73}]

From Elements database 20001107 [elements]:

  tantalum
  Symbol: Ta
  Atomic number: 73
  Atomic weight: 180.948
  Heavy blue-grey metallic transition element. Ta-181 is a stable isotope,
  and Ta-180 is a radioactive isotope, with a half-life in excess of 10^7
  years. Used in surgery as it is unreactive. Forms a passive oxide layer in
  air. Identified in 1802 by Ekeberg and isolated in 1820 by Jons J.
  Berzelius.