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A whitish, malleable, metallic element from the alkaline earth group. Barium occurs primarily as a sulfate (Barite) and less often as a carbonate (Witherite). Its abundance in the earth's crust is 0.05%. Barium was first isolated by Sir Humphrey Davy (1808) in England. Salts of barium are used as pigments, fillers, pesticides, and to produce the green color in fireworks. Barium pigments are used in paints, ceramics, glass, plastics, and rubber.

Synonyms and Related Terms

Ba; baryum (Fr.); bario (It., Esp.); Bário (Port.)


  • Barium metal and acid-soluble barium compounds are highly toxic.
  • Powdered metallic barium is highly flammable.
  • AciAlloys: SDS

Physical and Chemical Properties

Flame color is green. Reacts readily with water, ammonia, halogens, oxygen and most acids.

Composition Ba (atomic no. 56)
CAS 7440-39-3
Melting Point ~ 710 C
Density 3.6 g/ml
Molecular Weight atomic wt = 137.327
Boiling Point 1600 C

Resources and Citations

  • Chemical & Engineering News, American Chemical Society, Washington DC, 81 (36) , Sept. 8, 2003 Comment: Louisa Wray Dalton, p. 134
  • G.S.Brady, Materials Handbook, McGraw-Hill Book Co., New York, 1971
  • Richard S. Lewis, Hawley's Condensed Chemical Dictionary, Van Nostrand Reinhold, New York, 10th ed., 1993
  • The Merck Index, Martha Windholz (ed.), Merck Research Labs, Rahway NJ, 10th edition, 1983 Comment: entry 991
  • Van Nostrand's Scientific Encyclopedia, Douglas M. Considine (ed.), Van Nostrand Reinhold, New York, 1976
  • Random House, Webster's Encyclopedic Unabridged Dictionary of the English Language, Grammercy Book, New York, 1997
  • The American Heritage Dictionary or Encarta, via Microsoft Bookshelf 98, Microsoft Corp., 1998