Barium

Revision as of 22:45, 8 August 2012 by WikiBot (talk | contribs) (Bot: Automated text replacement (-{{SIB}} + & -{{EH}} + & -{{EJ}} + & -{{Editor Help}} + & -{{Editor Join}} +))
Jump to navigation Jump to search

Template:Elementbox header Template:Elementbox series Template:Elementbox groupperiodblock Template:Elementbox appearance img Template:Elementbox atomicmass gpm Template:Elementbox econfig Template:Elementbox epershell Template:Elementbox section physicalprop Template:Elementbox phase Template:Elementbox density gpcm3nrt Template:Elementbox densityliq gpcm3mp Template:Elementbox meltingpoint Template:Elementbox boilingpoint Template:Elementbox heatfusion kjpmol Template:Elementbox heatvaporiz kjpmol Template:Elementbox heatcapacity jpmolkat25 Template:Elementbox vaporpressure katpa Template:Elementbox section atomicprop Template:Elementbox crystalstruct Template:Elementbox oxistates Template:Elementbox electroneg pauling Template:Elementbox ionizationenergies3 Template:Elementbox atomicradius pm Template:Elementbox atomicradiuscalc pm Template:Elementbox covalentradius pm Template:Elementbox section miscellaneous Template:Elementbox magnetic Template:Elementbox eresist ohmmat20 Template:Elementbox thermalcond wpmkat300k Template:Elementbox thermalexpansion umpmkat25 Template:Elementbox speedofsound rodmpsat20 Template:Elementbox youngsmodulus gpa Template:Elementbox shearmodulus gpa Template:Elementbox bulkmodulus gpa Template:Elementbox mohshardness Template:Elementbox cas number |- ! colspan="2" style="background:#ffdead; color:black" | Selected isotopes |- | colspan="2" |

iso NA half-life DM DE (MeV) DP

Template:Elementbox isotopes stable Template:Elementbox isotopes stable Template:Elementbox isotopes decay Template:Elementbox isotopes stable Template:Elementbox isotopes stable Template:Elementbox isotopes stable Template:Elementbox isotopes stable Template:Elementbox isotopes stable Template:Elementbox isotopes end Template:Elementbox footer

WikiDoc Resources for Barium

Articles

Most recent articles on Barium

Most cited articles on Barium

Review articles on Barium

Articles on Barium in N Eng J Med, Lancet, BMJ

Media

Powerpoint slides on Barium

Images of Barium

Photos of Barium

Podcasts & MP3s on Barium

Videos on Barium

Evidence Based Medicine

Cochrane Collaboration on Barium

Bandolier on Barium

TRIP on Barium

Clinical Trials

Ongoing Trials on Barium at Clinical Trials.gov

Trial results on Barium

Clinical Trials on Barium at Google

Guidelines / Policies / Govt

US National Guidelines Clearinghouse on Barium

NICE Guidance on Barium

NHS PRODIGY Guidance

FDA on Barium

CDC on Barium

Books

Books on Barium

News

Barium in the news

Be alerted to news on Barium

News trends on Barium

Commentary

Blogs on Barium

Definitions

Definitions of Barium

Patient Resources / Community

Patient resources on Barium

Discussion groups on Barium

Patient Handouts on Barium

Directions to Hospitals Treating Barium

Risk calculators and risk factors for Barium

Healthcare Provider Resources

Symptoms of Barium

Causes & Risk Factors for Barium

Diagnostic studies for Barium

Treatment of Barium

Continuing Medical Education (CME)

CME Programs on Barium

International

Barium en Espanol

Barium en Francais

Business

Barium in the Marketplace

Patents on Barium

Experimental / Informatics

List of terms related to Barium


Overview

Barium (Template:PronEng) 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:

  • Barium compounds, and especially barite (BaSO4), 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 X-ray imaging of the digestive system ("barium meals" and "barium enemas").
  • 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 electrodes of fluorescent lamps, which facilitates the release of electrons.
  • The metal is a "getter" in vacuum tubes, to remove the last traces of oxygen.
  • Barium carbonate is used in glassmaking. 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 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[1] 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 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 (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.[1] 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


af:Barium ar:باريوم bn:বেরিয়াম be:Барый bs:Barijum bg:Барий ca:Bari (element) cs:Baryum co:Bariu da:Barium de:Barium et:Baarium el:Βάριο eo:Bario fa:باريوم fur:Bari 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 no:Barium nn:Barium oc:Bari (quimia) qu:Baryu scn:Bariu simple:Barium sk:Bárium sl:Barij sr:Баријум sh:Barijum fi:Barium sv:Barium ta:பேரியம் th:แบเรียม uk:Барій

Template:WH Template:WikiDoc Sources