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Selenium

Selenium is a chemical element with symbol Se and atomic number 34.

Selenium was discovered in 1818 by Jons Jakob Berzelius who observed the residue of sulphuric acid.
At first this residue was thought to be the element tellurium that was discovered 30 years earlier. However after some researches it became clear that the substance was just similar to tellurium but it has some different properties.
According to this similarity new element was named after the latin word for ‘moon’ (selene) as tellurium name came from the latin word for ‘earth’ (tellus). As moon is the satellite of the earth, selenium is the satellite of tellurium.

Characteristics

Selenium exists in several forms (allotropes) which shape and colour changes upon heating and cooling. One form of selenium is amorphous, brick-red powder. When quickly melted, it gets another appearance – the vitreous form. In this form it is black, brittle and lustrous solid. The most stable and dense allotrope of selenium is gray coloured metallic form that has an important feature as semiconductor showing appreciable photoconductivity.

Selenium is chemically related to tellurium and sulfur as it is the member of the same chemical family – the chalcogen family. Tellurium and selenium compounds are similar.

Applications

Nowdays selenium has two main applications: in glass-making and electronics.

In glass-making selenium perform as two different even contrary agents. First, it can be used as discolourant to eliminate green or yellow tints that iron compounds add to glass. So colorless glass is achieved by adding selenium. Contrariwise selenium can be used as colourant to add ruby red colour to glass. Thanks to its colouring properties selenium is used as pigment not only for glass but also for paints, plastics, ceramics and glazes.

Selenium is often applied in electronic products due to its semiconductor properties and other features. It is used especially in plain-paper photocopiers, laser printers, computers transistors and cellular phones. It also plays an important role in solar cells.

Selenium likewise tellurium is used in metal industry as addition to alloys in order to improve machinability. Small amounts of selenium compounds can be used in the rubber production.

Now the biological importance of selenium is being studied, for which reason some new applications for selenium has been found (e.g. in special compounds to improve soil, as ingredient in livestock feed etc.).

Our company provides the following Selenium metal and compounds.

Product Formula / Molecular Weight Form Application
Selenium Metal Se / 78.96 powder, shot, ingot Glass
colourants/discolourants, pigments, light-sensitive
materials, free-cutting stainless steel, CIGS solar cell
Bismuth Selenium Bi2Se3 /
70:30
ingot Free-cutting brass additive
(lead-free), post-machining steel enhancer
Ferro Selenium FeSe / Fe:Se = 50:50 ingot (3~20mm) Free-cutting stainless steel
etc.
Metal Selenide CuSe, NiSe, ZnSe ingot Free-cutting stainless steel,
post-machining steel enhancer etc.
Selenium Dioxide SeO2 / 110.96 powder Oxidant, catalyst, aluminium
surface-treating agent, glass colourant
Selenite Compounds HSeO3, KSeO3,
NaSeO3, BaSeO3, ZnSeO3
powder Glass colourant, aluminium
surface-treating agent, livestock feed
Selenate Compounds KSeO4, NaSeO4,
BaSeO4, ZnSeO4
powder Glass colourant/decolourant,
livestock feed
Selenium Disulfide SeS2 / 143.08 powder Ingredient for dandruff
shampoos, animal medicines etc.

If you have any questions or want to make an order please contact us anytime. We will be glad to help you.