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When present in compounds barium exists usually in the Ba 2+ , divalent state. Barium dissolves in most aqueous acids except sulfuric acid, due to the formation of an insoluble protective layer of barium sulfate.
Barium was first isolated in 1808 by English chemist Sir Humphry Davy (1778-1829). In 1807 and 1808, Davy also discovered five other new elements: sodium, potassium, strontium, calcium, and magnesium.arium had first been identified as a new material in 1774 by Swedish chemist Carl Wilhelm Scheele (1742-86). The form with which Scheele worked, however, was a compound of barium, barium sulfate (BaSO 4). Barium sulfate is, in fact, the most common naturally occurring ore of barium.