This element is no longer available.
Barium is a silvery-white metal that can be found in the environment, where it exists naturally. It occurs combined with other chemicals, such as sulphur, carbon or oxygen. Ii is very light and its density is half that of iron. Barium oxidizes in air, reacts vigorously with water to form the hydroxide, liberating hydrogen. Barium reacts with almost all the non-metals, forming often poisoning compounds.
Barium is often used in barium-nickel alloys for spark-plug electrodes an in vacuum tubes as drying and oxygen-removing agent. It is also used in fluorescent lamps: impure barium sulphide phosphoresces after exposure to the light.
Barium compounds are used by the oil and gas industries to make drilling mud. Drilling mud simplifies drilling through rocks by lubricating the drill.
Barium compounds are also used to make paint, bricks, tiles, glass, and rubber. Barium nitrate and chlorate give fireworks a green colour.