Selenium

Selenium is a chemical element with the symbol Se and atomic number 34. It is a nonmetal with properties intermediate between those of its periodic table neighbors sulfur and tellurium. It exists in several allotropic forms, including a red amorphous powder, a black vitreous form, and a gray crystalline form.

This trace element is naturally found in certain foods like nuts, grains, and meat, and is also available as a dietary supplement. It plays a role in various biological processes, including antioxidant defense and thyroid hormone metabolism. Selenium is used in industries such as glass manufacturing, pigments, and electronics.