History

(Gr. barys: heavy) Baryta was distinguished from lime by Scheele in 1774; the element was discovered by Sir Humphrey Davy in 1808.

Sources

It is found only in combination with other elements, chiefly with sulfate and carbonate and is prepared by electrolysis of the chloride.

Properties

Barium is a metallic element, soft, and when pure is silvery white; it belongs to the alkaline earth group, chemically resembling calcium . The metal oxidizes very easily and should be kept under petroleum or other suitable oxygen-free liquids to exclude air. It is decomposed by water or alcohol. 
A Periodic Table of the Elements at Los Alamos National Laboratory