Barium oxide
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2008-06-24T00:43:36Z
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{{Chembox new
| Name = Barium oxide
| OtherNames = Barium monoxide; barium protoxide; calcined baryta
| Section1 = {{Chembox Identifiers
| CASNo = 1304-28-5
}}
| Section2 = {{Chembox Properties
| Formula = BaO
| MolarMass = 153.3 g/mol
| Appearance = white solid
| Density = 5.7 g/cm³, solid
| Solubility = 3.8 g/100 ml (20 °C)
| MeltingPt = 1923 °C
| BoilingPt = ~2000 °C
}}
| Section3 = {{Chembox Structure
| Coordination = [[octahedron|Octahedral]]
| CrystalStruct = [[cubic]]
}}
| Section7 = {{Chembox Hazards
| EUClass = Harmful ('''Xn''')
| RPhrases = {{R20/22}}
| SPhrases = {{S2}}, {{S28}}
| FlashPt = non-flammable
}}
| Section8 = {{Chembox Related
| OtherAnions = [[Barium hydroxide]]<br />[[Barium peroxide]]
| OtherCations = [[Calcium oxide]]<br />[[Strontium oxide]]
}}
}}
'''Barium oxide''', BaO, is a white [[hygroscopic]] [[chemical compound|compound]] formed by the burning of [[barium]] in [[oxygen]], although it is often formed through the decomposition of other [[barium compounds|barium salts]].<ref> {{cite web | title = Compounds of barium:
barium (II) oxide | work = Web Elements | publisher = The University of Sheffield | date = 2007-01-26 | url = http://www.webelements.com/webelements/compounds/text/Ba/Ba1O1-1304285.html | accessdate = 2007-02-22 }}</ref>
: 2Ba + O<sub>2</sub> → 2BaO
: BaCO<sub>3</sub> → BaO + CO<sub>2</sub>
It transforms into [[barium hydroxide]] on contact with water.
: BaO + H<sub>2</sub>O → Ba(OH)<sub>2</sub>
==Uses==
Barium oxide is used as a coating for [[hot cathode]]s, and in [[cathode ray tube]]s. It is used in the production of certain kinds of glass such as optical [[crown glass (optics)|crown glass]]. It replaced [[lead oxide]]. Lead oxide was used to raise the [[refractive index]], but it also raised the dispersive power. Barium oxide only raises the refractive index.<ref> {{cite web | title = Barium Oxide (chemical compound) | work = Encyclopædia Britanica | publisher = Encyclopædia Britanica | date = 2007 | url = http://www.britannica.com/eb/topic-53368/barium-oxide | accessdate = 2007-02-19 }}</ref> Barium oxide also has use as an [[Ethoxylation|ethoxylation catalyst]] in the reaction of [[ethylene oxide]] and [[alcohol]]s, which takes place between 150 and 200°C.<ref>{{Citation | last = Nield | first = Gerald | last2 = Washecheck | first2 = Paul | last3 = Yang | first3 = Kang | title = United States Patent 4210764 | date = 05-04 | year = 1979 | url = http://www.freepatentsonline.com/4210764.html | access-date = 2007-02-20 }}</ref>
==Safety issues==
Barium oxide is an [[irritant]]. If it contacts the skin or the eyes or is inhaled it causes pain and redness. However, it is more dangerous when ingested. It can cause [[nausea|nausea]] and [[diarrhea|diarrhea]], [[paralysis|muscle paralysis]], cardiac arrhythmia, and can cause death. If ingested, medical attention should be sought immediately.
Barium oxide also is dangerous to the environment. It is harmful especially to [[Marine biology|aquatic organisms]]<ref> {{cite web | title = Barium Oxide (ICSC) | publisher = IPCS | date = October 1999 | url = http://www.inchem.org/documents/icsc/icsc/eics0778.htm | accessdate = 2007-02-19 }}</ref>
==References==
<references/>
==External links==
*[http://www.ilo.org/public/english/protection/safework/cis/products/icsc/dtasht/_icsc07/icsc0778.htm International Chemical Safety Card 0778]
[[Category:Barium compounds]]
[[Category:Oxides]]
[[ar:أكسيد باريوم]]
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[[ja:酸化バリウム]]
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[[zh:氧化钡]]