AskDefine | Define barium

Dictionary Definition

barium n : a soft silvery metallic element of the alkali earth group; found in barite [syn: Ba, atomic number 56]

User Contributed Dictionary

see Barium

English

Noun

  1. a metallic chemical element (symbol Ba) with an atomic number of 56.

Translations

External links

For etymology and more information refer to: http://elements.vanderkrogt.net/elem/ba.html (A lot of the translations were taken from that site with permission from the author)

Finnish

Noun

  1. barium

Extensive Definition

Barium () is a chemical element. It has the symbol Ba, and atomic number 56. Barium is a soft silvery metallic alkaline earth metal. It is never found in nature in its pure form due to its reactivity with air. Its oxide is historically known as baryta but it reacts with water and carbon dioxide and is not found as a mineral. The most common naturally occurring minerals are the very insoluble barium sulfate, BaSO4 (barite), and barium carbonate, BaCO3 (witherite). Benitoite is a rare gem containing barium.

Notable characteristics

Barium is a metallic element that is chemically similar to calcium but more reactive. This metal oxidizes very easily when exposed to air and is highly reactive with water or alcohol, producing hydrogen gas. Burning in air or oxygen produces not just barium oxide (BaO) but also the peroxide. Simple compounds of this heavy element are notable for their high specific gravity. This is true of the most common barium-bearing mineral, its sulfate barite BaSO4, also called 'heavy spar' due to the high density (4.5 g/cm³).

Applications

Barium has some medical and many industrial uses:

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, from which "barium" was derived 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 crystallized barium sulfate. Because barite is so insoluble, it cannot be used directly for the preparation of other barium compounds. Instead, the ore is heated with carbon to reduce it to barium sulfide
BaSO4 + 2CBaS + 2CO2
The barium sulfide is then hydrolyzed or reacted with acids to form other barium compounds such as the chloride, nitrate, and carbonate.
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, barium chloride, sulfate, carbonate, nitrate, and chlorate.

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-lives in the several millisecond to several minute range. The only notable exceptions are 133Ba which has a half-life of 10.51 years, and 137mBa (2.55 minutes).

Precautions

All water or acid soluble barium compounds are extremely poisonous. At low doses, barium acts as a muscle stimulant, while higher doses affect the nervous system, causing cardiac irregularities, tremors, weakness, anxiety, dyspnea and paralysis. This may be due to its ability to block potassium ion channels which are critical to the proper function of the nervous system.
Barium sulfate can be taken orally because it is highly insoluble in water, and is eliminated completely from the digestive tract. Unlike other heavy metals, barium does not bioaccumulate. However, inhaled dust containing barium compounds can accumulate in the lungs, causing a benign condition called baritosis.
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.
Barium acetate could lead to death in high doses. Marie Robards poisoned her father with the substance in Texas in 1993. She was tried and convicted in 1996.

References

External links

barium in Afrikaans: Barium
barium in Arabic: باريوم
barium in Bengali: বেরিয়াম
barium in Belarusian: Барый
barium in Bosnian: Barijum
barium in Bulgarian: Барий
barium in Catalan: Bari (element)
barium in Czech: Baryum
barium in Corsican: Bariu
barium in Welsh: Bariwm
barium in Danish: Barium
barium in German: Barium
barium in Estonian: Baarium
barium in Modern Greek (1453-): Βάριο
barium in Spanish: Bario
barium in Esperanto: Bario
barium in Basque: Bario
barium in Persian: باریوم
barium in French: Baryum
barium in Friulian: Bari
barium in Irish: Bairiam
barium in Manx: Baarium
barium in Galician: Bario
barium in Korean: 바륨
barium in Armenian: Բարիում
barium in Croatian: Barij
barium in Ido: Bario
barium in Indonesian: Barium
barium in Icelandic: Barín
barium in Italian: Bario
barium in Hebrew: בריום
barium in Javanese: Barium
barium in Swahili (macrolanguage): Bari
barium in Haitian: Baryòm
barium in Kurdish: Baryûm
barium in Latin: Barium (elementum)
barium in Latvian: Bārijs
barium in Luxembourgish: Barium
barium in Lithuanian: Baris
barium in Lojban: tijyjinme
barium in Hungarian: Bárium
barium in Malayalam: ബേരിയം
barium in Maori: Konu-okehu
barium in Dutch: Barium
barium in Japanese: バリウム
barium in Norwegian: Barium
barium in Norwegian Nynorsk: Barium
barium in Occitan (post 1500): Bari (quimia)
barium in Polish: Bar (pierwiastek)
barium in Portuguese: Bário
barium in Romanian: Bariu
barium in Quechua: Baryu
barium in Russian: Барий
barium in Sicilian: Bariu
barium in Simple English: Barium
barium in Slovak: Bárium
barium in Slovenian: Barij
barium in Serbian: Баријум
barium in Serbo-Croatian: Barijum
barium in Saterfriesisch: Barium
barium in Finnish: Barium
barium in Swedish: Barium
barium in Tamil: பேரியம்
barium in Thai: แบเรียม
barium in Vietnamese: Bari
barium in Turkish: Baryum
barium in Ukrainian: Барій
barium in Chinese: 钡
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