iso	NA	half-life	DM	DE M eV	DP
¹³⁰Ba	0.106%	Ba is stable with 74 neutrons
¹³²Ba	0.101%	Ba is stable with 76 neutrons
¹³³Ba	{syn.}	10.51 y	epsilon	0.517	¹³³Cs
¹³⁴Ba	2.417%	Ba is stable with 78 neutrons
¹³⁵Ba	6.592%	Ba is stable with 79 neutrons
¹³⁶Ba	7.854%	Ba is stable with 80 neutrons
¹³⁷Ba	11.23%	Ba is stable with 81 neutrons
¹³⁸Ba	71.7%	Ba is stable with 82 neutrons

SI units & STP are used except where noted.

Barium is a chemical element in the periodic table that has the symbol Ba and atomic number 56. A soft silvery metallic element, barium is an alkaline earth metal and melts at a very high temperature. Its oxide is called baryta and it is primarily found in the mineral barite but is never found in its pure form due to its reactivity with air. Compounds of this metal are used in small quantities in paints and in glassmaking.

Notable Characteristics

Barium is a metallic element that is chemically similar to calcium, yet is soft and in its pure form is silvery white resembling lead. This metal oxidizes very easily and when exposed to air and is highly reactive with water or alcohol. Barium is decomposed by water or alcohol. Some of the compounds of this element are remarkable for their high specific gravity, as its sulphate, called heavy spar.

Applications

Barium is primarily used in sparkplugs, vacuum tubes, fireworks, and in fluorescent lamps. Also:

A "getter" in vacuum tubes.
Barium sulfate is permanent white and is used in paint, in X-ray diagnostic work, and in glassmaking.
Barite is used extensively as a weighing agent in oil well drilling fluids and in rubber production.
Barium carbonate is a useful rat poison, while barium nitrate and chlorate give colors in fireworks.
Impure barium sulfide phosphoresces after exposure to the light.
Barium salts are sometimes used in medical procedures, such as X-raying the digestive system.
Lithopone, a pigment that contains barium sulfate and zinc sulfide, has good covering power, and does not darken in when exposed to sulfides.

History

Barium (Greek "barys" meaning "heavy") was first identified in 1774 by Carl Scheele and extracted in 1808 by Sir Humphry Davy in England. The oxide was at first called barote, by Guyton de Morveau, which was changed by Antoine Lavoisier to baryta, which soon was modified to "barium" to describe the metal.

Occurrence

Because barium quickly becomes oxidized in air, it is difficult to obtain this metal in its pure form. It is primarily found in and extracted from the mineral barite which is crystalized barium sulphate.
Barium is commercially produced through the electrolysis of molten barium chloride (BaCl₂) Isolation (* follow):
(cathode) Ba²⁺* + 2e^- ---> Ba (anode) Cl^-* --> ½Cl₂ (g) + e^-

Compounds

The most important compounds are barium peroxide, chloride, sulfate, carbonate, nitrate, and chlorate. When burned, barium salts glows green. (See "Uses" section above)

Isotopes

Naturally occurring barium is a mix of seven stable isotopes. There are twenty-two isotopes known, but most of these are highly radioactive and have half-lifes in the several millisecond to several minute range. The only notable exception is barium-133 which has a half-life of 10.51 years.

Precautions

All water or acid soluble barium compounds are extremely poisonous.
Oxidation occurs very easily and to remain pure, barium should be kept under a petroleum-based fluid (such as kerosene) or other suitable oxygen-free liquids that exclude air.

External Links

Barium is also the latin name for the city Bari in Italy.

Referenced By

Compose Your Message

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Barium".