selenium7

Selenium is a chemical element with the symbol Se and atomic number 34. It is a nonmetal and a semiconductor. Selenium was discovered in 1817 by Swedish chemist Jöns Jacob Berzelius, who named it after the Greek word selene, meaning "moon."

Selenium is found in various forms, including crystalline, amorphous, and colloidal. It is a trace element that is essential for human health, playing a role in antioxidant defense, thyroid hormone metabolism, and immune function. However, excessive intake of selenium can be toxic.

Selenium compounds are used in a variety of applications. Selenium dioxide is used as an oxidizing agent and a catalyst in organic synthesis. Selenium sulfide is an antifungal agent used in antidandruff shampoos. Selenium is also used in photoelectric cells, light meters, and xerography.

The production of selenium primarily occurs as a byproduct of copper refining. Major producers of selenium include China, Russia, and the United States. The price of selenium can fluctuate based on demand and supply.

In its elemental form, selenium is a brittle, silvery-gray solid. It has a relatively low melting point and sublimes when heated. Selenium's electrical conductivity is light-dependent, a property known as photoconductivity, which makes it useful in electronic devices.

Selenium plays a role in various biological processes, but its exact mechanisms and optimal dietary intake are still areas of ongoing research. Deficiency and toxicity are both concerns, highlighting the importance of balanced exposure.