描述
Sulfur or sulphur is the chemical element with atomic number 16, represented by the symbol S. At normal conditions, sulfur atoms form cyclic octatomic molecules with chemical formula S8. Elemental sulfur is a bright yellow crystalline solid. In nature, sulfur can be found as the pure element and as sulfide and sulfate minerals. Sulfur is an essential element for all life, and is widely used in biochemical processes. Sulfur in organic form is present in the vitamins biotin and thiamine. Sulfur is an important part of many enzymes and also in antioxidant molecules like glutathione and thioredoxin. Organically bonded sulfur is a component of all proteins, as the amino acids cysteine and methionine. Disulfide bonds are largely responsible for the mechanical strength and insolubility of the protein keratin, found in outer skin, hair, and feathers, and the element contributes to their pungent odor when burned.