Selenium

What is Selenium ?

Selenium

Selenium is a chemical element of atomic number 34, represented by the chemical symbol Se, an atomic mass of 78.96. It is a non-metal, chemicals with sulfur and tellurium, and rarely occurs in the element of character. It is toxic in large quantities, but the traces of which are for the cellular function in most, if not all, animals, the center of the activity of enzymes Glutathione peroxidase and thiorédoxines reductase (which indirectly reduce “oxidation of the molecules of certain animals and some plants) and three deiodinase enzymes known (converter, thyroid hormone to another). Selenium requirements in plants differ by species, with some plants apparently requiring none.

Isolated selenium in different forms, the stable, which is a grayish-purple semi-dense (semiconductor), forming a trigonal polymer chain. A better management of electricity, the light in the darkness, and is used in photocells. Selenium is also present in many forms of non-drivers, such as a glass of black allotrope, and various forms of crystalline red eight built cyclic molecules, like its lighter chemical cousin sulfur.

Selenium is available in commercial quantities of sulphide minerals as pyrite, partial substitution of sulfur in the mineral matrix. Minerals, hydrogen or selinioucho séléniate compounds are also known, but all are rare.

Selenium is naturally in a number of inorganic forms, including selenide, selenate and selenite. In soil, selenium appears to soluble as selenate (as sulphate), which are leached into rivers very easily by runoff.

Selenium is a biological, and hydrogen to organic dimethyl selinioucho, selenomethionine, selenocysteine and methylselenocysteine. In these compounds, selenium plays a role similar to that of sulfur.

Selenium is usually hydrogen in many selenide sulfur minerals like copper, silver or lead. It is a by-product of processing of these ores, from the anode mud of copper refineries and the mud from the lead chambers of sulfuric acid plants. The sludge can be treated with a range of resources for free selenium.

Natural sources of selenium include certain selenium-rich soils, and selenium that has been bioconcentrated by certain toxic plants such as locoweed. The anthropogenic sources of selenium include the burning of coal and mining industry and smelting of sulfide ores.

Applications :

Chemistry :
Selenium is a catalysts for many chemical reactions and is widely used in various industrial units and laboratory equipment, especially Organoselenium chemistry. It is also that in determining the structure of proteins and nucleic acids using X-ray crystallography (to include one or more items with MAD and SAD phasing.)

Manufacture and use of materials :
The largest use of selenium in the world for the manufacture of glass and ceramics, for the red color in glass, enamels and varnishes, and remove the color of the glass from the green color from iron impurities.
Selenium is bismuth brass replace toxic lead. It is also used to improve the abrasion resistance of vulcanized rubber.

Electronics :
Due to the properties and photovoltaic senior picture, the selenium is in the copier, photocells, light meters and solar cells. It was the rectifier. These applications are often used by properties with silicon, or to be replaced. The most notable exception is in power DC surge protection, where the superior energy capabilities of selenium suppressors make them more desirable than metal oxide varistors.

Press Amorphous selenium to convert the X-ray images on the structure and functions of the semiconductor in xeroradiography, flat panel x-ray cameras.

Photography :
Selenium is used in the toning of photographic prints, and it is sold as a toner by numerous photographic manufacturers including Kodak and Fotospeed. Its use intensifies and extends the tonal range of black and white photographic images as well as improving the permanence of prints.

For medical purposes :
Selenium disulphide SeS₂ or Selenium (IV) sulfide, containing the active ingredient in some shampoos. The effect of the active ingredient to kill scalp fungus Malassezia which causes shedding of dry skin fragments.. The substance is also in the body lotion for the treatment of Tinea Versicolor by infection with another type of fungus Malassezia.

Nutrition :
Selenium is widely distributed in vitamins and other supplements in small amounts (usually 50 to 200 micrograms per day for adult humans). Some are equipped with feed and selenium.