Barium was discovered in 1808. Like calcium and magnesium, barium is found in minerals and in the sea. Barium occurs in substantial deposits of barytes, BaSO₄.

Barium is mainly used in:

• medical procedure. Because barium sulfate, BaSO₄, is opague to x-rays, it is used in x-ray diagnoses of gastrointestinal examinations. The patient drinks a "barium cocktail", a suspension of BaSO₄ in water, to outline the stomach and intestines for X-ray examination. Although all soluble barium salts are toxic, the procedure is safe because BaSO₄ is essentially insoluble.
• firework displays. Barium nitrate, Ba(NO₃)₂, gives fireworks a green colour.

Shown above is a sample of barium in argon. Storing barium in argon minimizes oxidation of the sample.

BCIT Chemistry Resource Center
http://nobel.scas.bcit.ca/resource/