Selenium

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Selen_1

Chemical element with atomic number (Se)

Selenium, ₀₀Se

Selenium is an element needed by the body only in very small amounts that helps maintain tissue elasticity.

Information about Selenium

Selenium is present in biologic systems in amino acids, such as selenocysteine and selenomethionine, usually as a part of proteins, which are referred to as selenoproteins. While selenium is present in many important enzyme systems, deficiency of selenium is rare. Selenium is a nonmetal chemical element with the symbol Se and atomic number 34. It is a rare element, found in the Earth's crust at an average concentration of just 0.05 parts per million. Selenium is a member of the chalcogen group on the periodic table, along with sulfur and tellurium.

History

Selenium was discovered in 1817 by Jöns Jakob Berzelius and Johan Gottlieb Gahn. It was named after the Greek word "σελήνη" (selene), which means "moon", because of its similarity to tellurium, which had been named after the Latin word "tellus", meaning "earth".

Occurrence

Selenium_pathways_and_transformations

Selenium is a relatively rare element, found in the Earth's crust at an average concentration of just 0.05 parts per million. It is found in a number of minerals, including the sulfides pyrite and galena, and the selenides naumannite and clausthalite.

Selenium is also present in someplants, particularly in those grown in soil with high selenium content. It is an essential trace element for many organisms, including humans, but can be toxic in large amounts.

Properties

Selenium has several allotropes, including black, red, and gray forms. It is a nonmetal with properties that are intermediate between those of metals and nonmetals. It is a semiconductor, meaning it can conduct electricity under certain conditions, and has a wide range of uses in electronics and other industries.

Selenium is also important for the human body, as it is a necessary nutrient in small amounts. It is involved in the production of thyroid hormones and has antioxidant properties. However, like many trace elements, it can be toxic in large amounts.

Uses

Selenium has a variety of uses in industry and technology. It is a key ingredient in many types of glass, including glass used in the production of photovoltaic cells. It is also used in the production of semiconductors, including the production of certain types of solar cells.

In addition, selenium has uses in the metallurgical industry, as a component of stainless steel and other alloys. It is also used in the production of pigments and as a catalyst in chemical reactions.

Selenium is also important for the human body, and is used in some dietary supplements. However, it can be toxic in large amounts and should be consumed only in the recommended amounts.

Deficiency of Selenium

Keshan disease, an endemic cardiomyopathy affecting children and young women in parts of China, has been linked to selenium deficiency, although other nutritional deficiencies or local factors may also may a role.

Template:Toxicity Excess selenium exposure can cause cirrhosis in laboratory animals, but toxicity in humans has been linked largely to skin, hair and nail changes. An outbreak of possible selenium toxicity due to a nutritional supplement was marked by nausea, diarrhea, irritability, fatigue, neuropathy, hair loss and nail changes, without liver test abnormalities.

Trace Elements in Tissues and Biologic Systems

Aluminum	Copper	Nickel
Antimony	Fluorine	Rubidium
Barium	Iodine	Selenium
Boron	Lead	Silver
Bromine	Lithium	Strontium
Cadmium	Manganese	Tin
Chromium	Mercury	Vanadium
Cobalt	Molybdenum	Zinc

• Dailymed label info on Selenium
• FDA Selenium