The Periodic Table

Phosphorus

Symbol: P
Atomic mass: 30.973762
Atomic number: 15
Electron configuration: 1s2 2s8 3s5
Discovered: 1669
Boiling point: 280.5 °C

Phosphorus is a chemical element with symbol P and atomic number 15. As an element, phosphorus exists in two major forms—white phosphorus and red phosphorus—but because it is highly reactive, phosphorus is never found as a free element on Earth.

With few exceptions, minerals containing phosphorus are in the maximally oxidized state as inorganic phosphate rocks.

The first form of elemental phosphorus to be produced (white phosphorus, in 1669) emits a faint glow when exposed to oxygen – hence the name, taken from Greek mythology, Φωσφόρος meaning "light-bearer").
Phosphorus is essential for life. Phosphates (compounds containing the phosphate ion, PO43−) are a component of DNA, RNA, ATP, and the phospholipids, which form all cell membranes. Demonstrating the link between phosphorus and life, elemental phosphorus was first isolated from human urine, and bone ash was an important early phosphate source. Phosphate mines contain fossils, especially marine fossils because phosphate is present in the fossilized deposits of animal remains and excreta. Low phosphate levels are an important limit to growth in some aquatic systems. The vast majority of phosphorus compounds produced are consumed as fertilizers. Phosphate is needed to replace the phosphorus that plants remove from the soil, and its annual demand is rising nearly twice as fast as the growth of the human population. Other applications include the role of organophosphorus compounds in detergents, pesticides, and nerve agents.