Name Barium
Symbol Ba
Atomic Number 56
Atomic Mass 137.327 atomic mass units
Number of Protons 56
Number of Neutrons 81
Number of Electrons 56
Melting Point 725.0 C
Boiling Point 1140.0 C
Density 3.51 grams per cubic centimeter
Normal Phase Solid
Family Alkaline Earth Metals
Period 6
Cost $55 per 100 grams



Origin of Name From the Greek word barys, meaning heavy
Date and Place of Discovery Identified in 1774 (Scheele)
Isolated in 1808 in London (Davy)
Discovered by Carl Wilhelm Scheele
Sir Humphrey Davy
Common Compounds
Interesting facts
  • All barium compounds that will dissolve in water or acid are poisonous
  • It oxidizes in air.
  • It reacts in water and forms hydroxide.
  • When it burns in air, peroxide is formed.
  • It ignites when exposed to moist air.
  • It will react with most nonmetals.
Common Uses
  • Spark plugs
  • X-ray imaging agent
  • Vacuum tubes
  • Fireworks (the green color)
  • Fluorescent lamps
  • Glass and pottery glaze
  • Rubber
  • Rat poison
  • Paint pigment
  • Safety matches
  • Water softener


Photo Courtesy of
Chemical Elements
Jefferson Lab
Mrs. Purdy's Web Page
Web Elements

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