White phosphorus, yellow phosphorus, or simply tetraphosphorus (P4) is an allotrope of phosphorus. It is a translucent waxy solid that quickly yellows in light (due to its photochemical conversion into red phosphorus), for this reason, impure white phosphorus is called yellow phosphorus. White phosphorus is the first allotrope of phosphorus that was discovered, isolated for the first time in 1669 by Henning Brand. High‑purity white laboratory‑grade samples are usually obtained by redistillation and recrystallization of commercial yellow phosphorus.