Symbol: Se

Atomic Number: 34

Atomic Weight: 78.96

Selenium (atomic number 32, symbol Se) is a nonmetal and a chemical element that is added to dietary supplements and is an essential mineral. It was first observed by the Swedish scientist Jons Jacob Berzelius. The element occurs in copper ores and rare minerals such as clausthalite, crooksite, and eucairite. It is also found in amino acids such as methylselenocysteine, selenocysteine, and selenomethionine. Selenium is found in ocean waters and some soils as well. Commercial production at mining sites and coal burning also release selenium, including smelting and extraction of sulfide ores. The element is obtained through the process of...Read More