Sodium selenite


Sodium selenite

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Section1= Chembox Identifiers
CASNo=10102-18-8
PubChem=24934
SMILES= [O-] [Se] (=O) [O-] . [Na+] . [Na+]

Section2= Chembox Properties
Formula=Na2SeO3
MolarMass=172.938
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Section3= Chembox Hazards
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Sodium selenite is a chemical compound with the formula Na2SeO3. This salt is the most common water soluble forms of selenium. The industrial production of selenium often involves the extraction of selenium dioxide from residues obtained during the purification of copper metal. Acidification of solutions of selenium dioxide followed by reduction with sulfur dioxide gives elemental selenium.

ynthesis and fundamental reactions

The sodium selenite salt is usually prepared by the reaction of selenium dioxide with sodium hydroxide::SeO2 + 2 NaOH → Na2SeO3 + H2OAcidification of selenium dioxide gives selenous acid, which, unlike sulfurous acid, is isolable. [Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. ISBN 0-12-352651-5.]

Akin to the related salt sodium sulfite, Na2SeO3 features a pyramidal dianion SeO32- with C3v symmetry. Oxidation of this anion give sodium selenate, Na2SeO4.

Applications

Together with the related barium and zinc salts, sodium selenite is mainly used in the manufacture of colorless glass. Its pink coloration cancels out the green color imparted by iron impurities. [Bernd E. Langner "Selenium and Selenium Compounds" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2002. doi|10.1002/14356007.a23_525 Article Online Posting Date: June 15, 2000]

afety

Selenium is an essential element (animals require selenium for selenium-dependent enzymes such as glutathione peroxidase. [ [http://lpi.oregonstate.edu/infocenter/minerals/selenium/ Linus Pauling Institute at Oregon State University] lpi.oregonstate.edu] ). Sodium selenite is currently used in some food supplements in microgram quantities, but it is toxic at higher levels, the acute toxicity differs from the chronic toxicity which for selenite the chronic toxic dose for human beings is about 2400 to 3000 micrograms of selenium per day for a long time. [Wilber CG, Toxicology of selenium 1980 Clinical Toxicology volume 17, pages 171-230,(page211).] . See MSDS.

References

External links

* [http://lpi.oregonstate.edu/infocenter/minerals/selenium/ Linus Pauling Institute page on selenium]


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