Phosphorus

Phosphorus, chemical element, symbol P; for physical constants see Periodic Table. Phosphorus was discovered by Hennig Brand in 1669. The element is found in nature as phosphate rock containing apatite, an impure tri-calcium phosphate. It is prepared by heating tri-calcium phosphate with carbon in an electric furnace, with the vapor being collected under water. Phosphorus, a nonmetallic element, exists in three or more allotropic forms, white, red, and black. It catches fire spontaneously in air and must be kept under water. It may cause severe burns to the flesh and must be handled with forceps. It is an essential component of animal tissue and bone. Phosphorus and its compounds are used in fertilizers, fine china, safety matches, pesticides, incendiary weapons, cleaning agents, and water softeners.