___ Origin

Barium is an alkaline earth metal. With an estimated average content of 250 g/t within the earth crust, it is the 19th among all elements in atomic abundance.
Due to its high reactivity, barium is not found as a free metal in nature. The most important barium minerals are heavy spar BaSO4 and witherite BaCO3. Deposits of these minerals are located all over the world.
Barium metal is produced in two steps starting from the carbonate. BaCO3 is subjected to a reductive calcination. The resulting barium oxide is subsequently reacted to elemental barium under high vacuum. Further purification of barium may be facilitated by vacuum distillation.

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