View source for Barium

{{Elementbox_header | number=56 | symbol=Ba | name=barium | left=[[caesium]] | right=[[lanthanum]] | above=[[strontium|Sr]] | below=[[radium|Ra]] | color1=#ffdead | color2=black }}
{{Elementbox_series | [[alkaline earth metal]]s }}
{{Elementbox_groupperiodblock | group=2 | period=6 | block=s }}
{{Elementbox_appearance_img | Ba,56| silvery white }}
{{Elementbox_atomicmass_gpm | [[1 E-25 kg|137.327]][[List of elements by atomic mass|(7)]] }}
{{Elementbox_econfig | &#91;[[xenon|Xe]]&#93; 6s<sup>2</sup> }}
{{Elementbox_epershell | 2, 8, 18, 18, 8, 2 }}
{{Elementbox_section_physicalprop | color1=#ffdead | color2=black }}
{{Elementbox_phase | [[solid]] }}
{{Elementbox_density_gpcm3nrt | 3.51 }}
{{Elementbox_densityliq_gpcm3mp | 3.338 }}
{{Elementbox_meltingpoint | k=1000 | c=727 | f=1341 }}
{{Elementbox_boilingpoint | k=2170 | c=1897 | f=3447 }}
{{Elementbox_heatfusion_kjpmol | 7.12 }}
{{Elementbox_heatvaporiz_kjpmol | 140.3 }}
{{Elementbox_heatcapacity_jpmolkat25 | 28.07 }}
{{Elementbox_vaporpressure_katpa | 911 | 1038 | 1185 | 1388 | 1686 | 2170 | comment= }}
{{Elementbox_section_atomicprop | color1=#ffdead | color2=black }}
{{Elementbox_crystalstruct | cubic body centered }}
{{Elementbox_oxistates | 2<br />(strongly [[base (chemistry)|basic]] oxide) }}
{{Elementbox_electroneg_pauling | 0.89 }}
{{Elementbox_ionizationenergies3 | 502.9 | 965.2 | 3600 }}
{{Elementbox_atomicradius_pm | [[1 E-10 m|215]] }}
{{Elementbox_atomicradiuscalc_pm | [[1 E-10 m|253]] }}
{{Elementbox_covalentradius_pm | [[1 E-10 m|198]] }}
{{Elementbox_section_miscellaneous | color1=#ffdead | color2=black }}
{{Elementbox_magnetic | [[paramagnetism|paramagnetic]] }}
{{Elementbox_eresist_ohmmat20 | 332 n}}
{{Elementbox_thermalcond_wpmkat300k | 18.4 }}
{{Elementbox_thermalexpansion_umpmkat25 | 20.6 }}
{{Elementbox_speedofsound_rodmpsat20 | 1620 }}
{{Elementbox_youngsmodulus_gpa | 13 }}
{{Elementbox_shearmodulus_gpa | 4.9 }}
{{Elementbox_bulkmodulus_gpa | 9.6 }}
{{Elementbox_mohshardness | 1.25 }}
{{Elementbox_cas_number | 7440-39-3 }}
{{Elementbox_isotopes_begin | color1=#ffdead | color2=black }}
{{Elementbox_isotopes_stable | mn=130 | sym=Ba | na=0.106% | n=74 }}
{{Elementbox_isotopes_stable | mn=132 | sym=Ba | na=0.101% | n=76 }}
{{Elementbox_isotopes_decay | mn=133 | sym=Ba
 | na=[[synthetic radioisotope|syn]] | hl=10.51 [[year|y]]
 | dm=[[electron capture|ε]] | de=0.517 | pn=133 | ps=[[caesium|Cs]] }}
{{Elementbox_isotopes_stable | mn=134 | sym=Ba | na=2.417% | n=78 }}
{{Elementbox_isotopes_stable | mn=135 | sym=Ba | na=6.592% | n=79 }}
{{Elementbox_isotopes_stable | mn=136 | sym=Ba | na=7.854% | n=80 }}
{{Elementbox_isotopes_stable | mn=137 | sym=Ba | na=11.23% | n=81 }}
{{Elementbox_isotopes_stable | mn=138 | sym=Ba | na=71.7% | n=82 }}
{{Elementbox_isotopes_end}}
{{Elementbox_footer | color1=#ffdead | color2=black }}
{{SI}}


==Overview==
'''Barium''' ({{pronEng|ˈbɛəriəm}}) is a [[chemical element]]. It has the symbol '''Ba''', and [[atomic number]] 56. Barium is a soft silvery [[metal]]lic [[alkaline earth metal]]. It is never found in nature in its pure form due to its [[reactivity]] with [[Earth's atmosphere|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, BaSO<sub>4</sub> ([[barite]]), and barium [[carbonate]], BaCO<sub>3</sub> (witherite). Benitoite is a rare gem containing barium.

== Notable characteristics ==
Barium is a [[metal]]lic element that is chemically similar to [[calcium]] but more reactive. This metal [[oxidation|oxidizes]] very easily when exposed to air and is highly [[chemical reaction|reactive]] with [[water (molecule)|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]] BaSO<sub>4</sub>, also called 'heavy spar' due to the high density (4.5 g/cm³).

== Applications ==
Barium has some medical and many industrial uses:
*Barium compounds, and especially barite (BaSO<sub>4</sub>), are extremely important to the petroleum industry. Barite is used in drilling mud, a weighting agent in drilling new oil wells.
*[[Barium sulfate]] is used as a [[radiocontrast]] agent for [[medical imaging|X-ray imaging]] of the digestive system ("[[barium meal]]s" and "[[barium enema]]s").
*[[Barium carbonate]] is a useful [[rat poison]] and can also be used in making bricks. Unlike the sulfate, the carbonate dissolves in stomach acid, allowing it to be poisonous.
*An alloy with [[nickel]] is used in spark plug wire.
*[[Barium oxide]] is used in a coating for the [[electrode]]s of fluorescent lamps, which facilitates the release of [[electron]]s.
*The metal is a "getter" in vacuum tubes, to remove the last traces of [[oxygen]].
*[[Barium carbonate]] is used in [[glass]]making. Being a heavy element, barium increases the [[refractive index]] and luster of the glass.
*[[Barite]] is used extensively in [[rubber]] production.
*[[Barium nitrate]] and chlorate give green colors in fireworks.
*Impure barium sulfide [[phosphorescence|phosphoresces]] after exposure to the [[light]].
*[[Lithopone]], a [[pigment]] that contains [[barium sulfate]] and [[zinc sulfide]], is a permanent white that has good covering power, and does not darken in when exposed to sulfides.
*[[Barium peroxide]] can be used as a catalyst to start an aluminothermic reaction when welding rail tracks together. It can also be used in green [[tracer ammunition]].
*Barium titanate was proposed in 2007[http://www.technologyreview.com/Biztech/18086/] to be used in next generation battery technology for electric cars.
*Barium Fluoride is used in infrared applications.
*Barium is a key element in [[YBCO]] superconductors.

== History ==
Barium ([[Greek language|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. Barium is commercially produced through the [[electrolysis]] of molten [[barium chloride]] (BaCl<sub>2</sub>)
''Isolation'' (* follow):<br />
:([[cathode]]) Ba<sup>2+</sup>* + 2[[electron|e<sup>-</sup>]] → Ba ([[anode]]) Cl<sup>-</sup>* → ½Cl<sub>2</sub> ([[gas|g]]) + e<sup>-</sup>

== Compounds ==
The most important compounds are barium peroxide, barium chloride, [[barium sulfate|sulfate]], [[barium carbonate|carbonate]], [[barium nitrate|nitrate]], and chlorate.

== Isotopes ==
Naturally occurring barium is a mix of seven stable [[isotope]]s. There are twenty-two isotopes known, but most of these are highly [[radioactive]] and have [[half-life|half-lives]] in the several millisecond to several minute range. The only notable exceptions are <sup>133</sup>Ba which has a half-life of 10.51 years, and <sup>137m</sup>Ba (2.55 minutes).

== Precautions ==
All water or acid [[soluble]] barium compounds are extremely [[poison]]ous. 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 [[mouth|oral]]ly because it is highly insoluble in water, and is eliminated completely from the digestive tract. Unlike other [[heavy metals]], barium does not [[bioaccumulation|bioaccumulate]].<ref>http://www.epa.gov/region5/superfund/ecology/html/toxprofiles.htm#ba</ref>  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==
<references/>

== External links ==
* [http://www.webelements.com/webelements/elements/text/Ba/index.html WebElements.com &ndash; Barium]
* [http://elements.vanderkrogt.net/elem/ba.html Elementymology & Elements Multidict]

[[Category:Chemical elements]]
[[Category:Alkaline earth metals]]
[[Category:Toxicology]]
[[Category:Barium|*]]
[[Category:Barium compounds]]
[[Category:Barium minerals]]


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[[bg:Барий]]
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[[el:Βάριο]]
[[es:Bario]]
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[[fa:باريوم]]
[[fr:Baryum]]
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[[gl:Bario (elemento)]]
[[ko:바륨]]
[[hy:Բարիում]]
[[hr:Barij]]
[[io:Bario]]
[[id:Barium]]
[[is:Barín]]
[[it:Bario]]
[[he:בריום]]
[[sw:Bari]]
[[ht:Baryòm]]
[[ku:Baryûm]]
[[la:Barium (elementum)]]
[[lv:Bārijs]]
[[lb:Barium]]
[[lt:Baris]]
[[jbo:tijyjinme]]
[[hu:Bárium]]
[[mi:Konu-okehu]]
[[nl:Barium]]
[[ja:バリウム]]
[[no:Barium]]
[[nn:Barium]]
[[oc:Bari (quimia)]]
[[pl:Bar (pierwiastek)]]
[[pt:Bário]]
[[ro:Bariu]]
[[qu:Baryu]]
[[ru:Барий]]
[[scn:Bariu]]
[[simple:Barium]]
[[sk:Bárium]]
[[sl:Barij]]
[[sr:Баријум]]
[[sh:Barijum]]
[[fi:Barium]]
[[sv:Barium]]
[[ta:பேரியம்]]
[[th:แบเรียม]]
[[vi:Bari]]
[[tr:Baryum]]
[[uk:Барій]]
[[zh:钡]]

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