Phosphorus and Its Modification

**Symbol:** P

**Atomic number:** 15

**International title:** phosphorus

**General formula:** P₄

**Relative Atomic Weight:** 30,974

**Information:** Phosphorus is non-metallic and occurs in several alotropic modifications, the most common of which are white, red and black phosphorus. White phosphorus consists of four-molecule P₄ molecules. It is a very toxic and reactive substance of yellowish color. It is self-inflammatory and unstable. Red phosphorus is a relatively stable, non-toxic substance of the polymeric structure. Black phosphorus is a very stable substance, which in its properties is more like a metal.

**Use:** Red phosphor is used to make matches and is a raw material in the chemical industry.

**Occurrence:** In nature, phosphorus occurs only in the form of phosphorus compounds (also phosphates). The most important phosphorus mineral is apatite Ca₅(PO₄)₃X (where X = OH, F orCl), and Phosphorite Ca₃(PO₄)₂. Phosphorus is a biogenic element (it is contained, for example, in nucleic acids and in the form of phospholipids in biological membranes).