Barium

Barium, chemical element, symbol Ba; for physical constants see Periodic Table. Barium, a soft, silvery white metal, was discovered by Sir Humphrey Davy in 1808. In nature it is found chiefly as barite or heavy spar (sulfate) or witherite (carbonate). Barium is produced by electrolysis of its chloride and is easily oxidized. Barium sulfate (blanc fixe) has good covering power and does not darken in the presence of sulfides. It is used in pigments and as a filler in paper, as well as in X-ray diagnostic work and glassmaking. Other compounds of barium are used in fireworks and rat poison. Soluble barium compounds are poisonous.