Appearance and Characteristics
Harmful effects:
Barium compounds that are water or acid soluble are highly poisonous. Barium powder can ignite spontaneously in air. Barium sulfate, used in x-ray imaging, is highly insoluble in water, and is therefore nontoxic and completely removed from the digestive tract.
Characteristics:
Barium is a metallic element chemically resembling calcium but more reactive. It is a soft, silvery metal and when cut it quickly turns a black color due to the formation of barium oxide, (BaO).
It is also highly reactive with water or alcohol. When present in compounds barium exists usually in the Ba2+, divalent state. Barium dissolves in most aqueous acids except sulfuric acid, due to the formation of an insoluble protective layer of barium sulfate. Barium is most commonly found as the mineral barite (BaSO4) and witherite (BaCO3)
Uses of Barium
Barium is used as a “flashed getter” in vacuum tubes to remove the last traces of gases. Barium is an important element in yttrium barium copper oxide (YBCO) superconductors. An alloy of barium with nickel is used in sparkplug wire. Barium sulfate (barite) is used to increase the contrast in x-ray imaging of the digestive system.