Facts about selenium

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Who in their wildest dreams would have ever imagined a nonmetal being used to treat dandruff?
Is it also possible that the same metal be used in manufacturing glass?
Well, as absurd as this may sound, it is indeed true. The nonmetal selenium has various applications to its name.
Here are a few facts about this element.

1) Is it by chance or design that an element is discovered?
The trace element selenium was discovered in 1817 by a Swedish chemist Jons Jacob Berzelius. While working in a mine, Berzelius initially mistook the burning fumes to be tellurium until he realized that the mine did not have any tellutrium compound. Thus came the discovery of a new element Selenium! Selenium originates from the greek word Selene and the greek mythology referes to Selene as the greek goddess of the moon.

2) Properties of Selenium
Selenium is a rare element and a non metal and has many allotropic forms. Interconversion of these allotropes takes place at different temperatures. It is a red amorphous powder or vitreous black in colour. Stable form of selenium is usually metallic grey. Its atomic number is 34 and the symbol is Se. Although not very common, selenium does exist free in nature in a relatively pure form.

3) Isotopes of selenium
Selenium has 29 isotopes with only 6 being very stable. The six stable isotopes are Se -74, Se- 76, Se -77, Se- 78, Se -80 and Se- 82.

4) Sources of selenium
Selenium a bi product of copper sulphide ores and is found occurring naturally in crook site and clausthalite. It can also be obtained from copper refineries from the anode metal. Roasting of sludge and mud with sulphuric acid also helps in the recovery of selenium.

5) Selenium is used as a light sensor
The photoelectric effect of selenium was discovered by Willoughby smith and its use as a light sensor was in 1870. A Selenium based photophone was made by Alexander Graham Bell in 1879.

6) Other uses of selenium
Selenium is used for decolourising glass and also for making the pigment china red. Its use also extends to laser printers, photocopiers, semiconductors and in steel.

7) Growth of certain plants is an indicator of Selenium in the soil as they require high content of Selenium to grow.

8) Selenium and its compounds have antifungal properties
Due their antifungal action, Selenium salts are used in anti dandruff shampoos.

9) Selenium rich foods
Plants are the major dietary source of selenium apart from meat and Sea food. Brazil nuts are a rich source of selenium and a single nut has the necessary requirement of selenium for an adult.

10) Selenium is important for the formation of antioxidant enzymes
Selenium in combination with proteins forms an important antioxidant enzyme Selenoproteins. These Selenoproteins help in preventing cellular damage that occurs due to the formation of free radicals. Some selenoproteins also help in the regulation of thyroid function and immune system.

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