baryum

Baryum, known in English as barium, is a chemical element with symbol Ba and atomic number 56. It is a soft, silvery‑white alkaline earth metal and a member of group 2 of the periodic table. It is chemically reactive, especially with water and oxygen, and is typically stored under oil to prevent oxidation. In most compounds it exhibits a +2 oxidation state.

Occurrence and production: Barium occurs mainly in the minerals barite (barium sulfate, BaSO4) and witherite (barium carbonate, BaCO3). Barite is the dominant ore and is mined in multiple countries. The metal is produced by reducing barium compounds or oxides, often by electrolysis of molten chlorides or by reduction with reactive metals, followed by purification.

Chemistry and properties: Insoluble BaSO4 is widely used due to its inertness, while many other barium compounds are water‑soluble and toxic. BaO forms when barium is burned in air and Ba(OH)2 forms upon contact with water. The element reacts vigorously with water, releasing hydrogen gas and forming alkaline solutions.

Applications: Barium compounds have several uses. Barium sulfate is a radiopaque contrast agent for medical imaging and is used to outline the digestive tract in X‑ray studies. It is also used in drilling fluids to increase density and in phosphors and fireworks for green coloration. Barium metal and alloys have specialized roles in research, vacuum tubes, and certain ceramics.

Safety: Soluble barium salts are highly toxic if ingested or inhaled, necessitating careful handling and protective measures. Barium sulfate is largely insoluble and considered safe for medical use under supervision. The term baryum is used in some languages; barium is the standard English name.