barium

Name barium
Symbol Ba
Atomic Weight 137.327
Atomic Number 56
CAS ID 7440-39-3
Group Number 2
Group Name Alkaline Earth Metal
Period Number 6
Origin of Name Greek, barys = "heavy."
Year Discovered 1808
Discovery Credits Isolated by Sir Humphrey Davy at London, UK.
Class Metallic
Color silvery white
Standard State Solid at 77 F & 298 K
Description Relatively soft, silvery-white metal. Obtained from BaO on heating with aluminum. Attacked by air and water. Used mainly as BaSO4 in drilling fluids for oil and gas exploration; small amounts used in paints, glass, etc

Diagnostic tests: 
A yellowish green coloration of the flame test is given by all barium salts, except the silicates.
In solution, the presence of barium is proved by the heavy white precipitate formed by the addition of dilute H2SO4.

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