Barium

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{{Elementbox_isotopes_decay | mn=133 | sym=Ba| na=[synthetic radioisotope | hl=10.51 [year | dm=[electron capture | de=0.517 | pn=133 | ps=[caesium -->

Barium (International Phonetic Alphabet: ) 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 Earth's atmosphere. 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 oxidation very easily when exposed to air and is highly chemical reaction with water (molecule) 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 radioopaque (x-ray absorbant), used in X-ray diagnostic work for obtaining images 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 phosphorescence 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 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 "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 crystalized barium sulfate. Barium is commercially produced through the electrolysis of molten barium chloride (BaCl2)Isolation (* follow):
(cathode) Ba2+* + 2electron → Ba (anode) Cl-* → ½Cl2 (gas) + e-

See also :category:Barium minerals.

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

See also :category:Barium compounds.

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-life 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 used in medicine only because it does not dissolve, and is eliminated completely from the digestive tract. Unlike other heavy metals, barium does not bioaccumulation.http://www.epa.gov/region5/superfund/ecology/html/toxprofiles.htm#ba However, inhaled barium dust can accumulate in the lungs, 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

WebElements.com – Barium
Elementymology & Elements Multidict

Barium - Wikipedia, the free encyclopedia
Barium (pronounced /ˈbɛəriəm/) is a chemical element. It has the symbol Ba, and atomic number 56. Barium is a soft silvery metallic alkaline earth metal.

Barium enema Introduction - Health encyclopaedia - NHS Direct
Procedure for examining the lower intestine ... A barium enema is a procedure that is carried out using a special type of X-ray to examine the large bowel for problems, such as ...

Barium enema Risks - Health encyclopaedia - NHS Direct
Procedure for examining the lower intestine ... During a barium enema test, the risk of radiation exposure is low because a minimum dose of radiation is used.

Definition: barium from Online Medical Dictionary
The Online Medical Dictionary is a searchable dictionary of definitions from medicine, science and technology.

Visual Elements - Barium
Discovered : 1808 by Sir Humphry Davy Isolated in London, UK Origin : The name comes from the Greek ‘barys’, meaning heavy. Description : A soft silvery metal that rapidly ...

Barium Enema
A barium enema is an x-ray test to obtain pictures of your colon (the last part of the gut, sometimes called the large intestine or large bowel.)

Barium Swallow / Meal / Follow Through
An x-ray test where you drink a liquid that contains some barium sulphate can be used to obtain pictures of your upper gut - the gullet (oesophagus), stomach and small intestine.

barium - Hutchinson encyclopedia article about barium
Hutchinson encyclopedia article about barium. barium. Information about barium in the Hutchinson encyclopedia. barium sulfate, barium chloride, barium nitrate, barium carbonate ...

Barium procedures - Patient Information from The Royal College of ...
Barium X-Ray radiology procedures - patient experiences, staff explanations and equipment information

Cancer Research UK | CancerHelp UK | Barium X-ray
This page tells you about barium tests. You have this type of test if your doctor needs to look at the outline of any part of your digestive system.