The element with the atomic number 34 is selenium. It was discovered by Jons Jacob Berzelius, a Swedish chemist, in 1817. He discovered selenium while analyzing an impurity in sulphuric acid that was produced at a factory in Sweden. Berzelius thought that this impurity was tellurium at first, but he then realized that it was an unknown element. And because of its similarity to tellurium, he named it selenium after the word Selene – a word in Greek that means ‘moon goddess’.
Selenium began to be used on commercial levels by the mid-1870s when it was developed by Werner Siemens. A selenium cell was used in the photo-phone developed by Alexander Graham Bell in 1879.
This metal is also nutritionally essential for humans. We need selenium for healthy joints, hearts, and eyes. It is critical in DNA synthesis, in the activities of the immune system, and the reproductive system. Selenium also helps fight cancer, among other diseases. The human body cannot synthesize this element, and therefore, we have to provide it from outside sources. However, a little selenium is all that is needed for healthy functioning and too much selenium can be toxic.
Selenium exists in several allotropic forms, of which only three are generally recognized. Amorphous selenium is either red, in powder form, or black, in vitreous or glassy form. Crystalline hexagonal selenium is the most stable form of this metal. It resembles sulphur in its appearance.
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