fosfore

Fosfore is the chemical element with the symbol P and atomic number 15. It is a nonmetal that occurs in several allotropes, including white, red, violet, and black phosphorus. White phosphorus is highly reactive and glows faintly in the dark when exposed to air; because of its flammability it is stored under water.

Phosphorus is not found free in nature; it occurs in minerals such as apatite and other phosphate rocks. The main industrial route to elemental phosphorus is the reduction of phosphate ore with silica and coke in electric arc furnaces, producing white phosphorus that is condensed and collected. From white phosphorus, other phosphorus compounds are produced, including phosphoric acid and various phosphates used in fertilizers, as well as phosphorus chlorides and organophosphorus compounds for industrial uses. Red phosphorus is made by heating white phosphorus in the absence of air; it is more stable and is used in safety matches and flame retardants.

Phosphorus is essential for life and is a key constituent of DNA, RNA, ATP, and phospholipids. It is a major component of bones and teeth as calcium phosphate. In agriculture, phosphate fertilizers supply phosphorus to crops; fertilizers and food-grade additives rely on phosphates and phosphoric acid.

Safety and environment: White phosphorus is highly toxic; exposure can cause severe liver and kidney damage and burns. Handling requires strict controls. Phosphates from agricultural runoff can contribute to eutrophication of water bodies, and phosphate mining and processing raise environmental concerns. Regulation and improved practices aim to minimize ecological impact.