a nonmetallic chemical element with symbol P and atomic number 15. A multivalent pnictogen, phosphorus as a mineral is almost always present in its maximally oxidised state, as inorganic phosphate rocks. Elemental phosphorus exists in two major forms—white phosphorus and red phosphorus—but due to its high reactivity, phosphorus is never found as a free element on Earth.

Phosphorus occurs in white (extremely dangerous), red (safer and common in matches) and black (rare, most stable) forms. This exotic violet form is a mixture of red and black, not a true allotrope itself.