selênio

Selenium is a chemical element with the symbol Se and atomic number 34. It is a nonmetal with properties that are intermediate between those of the metals and the nonmetals. Selenium is found in the Earth's crust in trace amounts, primarily in sulfide ores. It is obtained commercially as a byproduct of copper refining. Selenium has several allotropes, with the most stable being a metallic gray form. It is a semiconductor and has applications in electronics and as a catalyst in chemical reactions.

Selenium is essential for life, particularly for animals. It is a component of the enzyme glutathione peroxidase, which is crucial for protecting cells from oxidative damage. Selenium deficiency can lead to Keshan disease, a heart muscle disease, and Kashin-Beck disease, a neurological disorder. Selenium is also used in medicine, particularly in the treatment of certain types of cancer.

In industry, selenium is used in the production of glass, which is made more resistant to ultraviolet light. It is also used in the manufacture of pigments, rubber accelerators, and in the production of certain types of steel. Selenium compounds are used in the production of electroplating solutions and in the manufacture of certain types of batteries. Selenium is also used in the production of certain types of solar cells, which convert sunlight into electricity.