phosphorus (P) /fos′fərəs/ [Gk, phos, light, pherein, to bear] , a nonmetallic chemical element occurring extensively in nature as a component of phosphate rock. Its atomic number is 15; its atomic mass is 30.975. Phosphorus forms a series of sulfides used commercially in the manufacture of matches. It can be prepared in yellow or white, red, and black allotropic forms. Phosphorus is essential for the metabolism of protein, calcium, and glucose. The body uses phosphorus in its combined forms, which are obtained from such nutritional sources as milk, cheese, meat, egg yolk, whole grains, legumes, and nuts. A nutritional deficiency of phosphorus can cause weight loss, anemia, and abnormal growth. Phosphorus is essential to the body for the production of adenosine triphosphate and for the process of glycolysis. Elemental white or yellow phosphorus is extremely poisonous and produces severe GI irritation. If ingested, it can produce hemorrhage, cardiovascular failure, and death. Chronic poisoning by phosphorus is characterized by anemia, cachexia, bronchitis, and necrosis of the mandible. Normal adult blood levels of phosphorus are 3 to 4.5 mg/dL or 0.97 to 1.45 mmol/L (SI units).
