Red phosphorus is used in the manufacture of safety matches. This is due to the fact that

Red phosphorus is used in safety matches primarily because it is significantly more stable and less reactive than white phosphorus at ordinary temperatures. While white phosphorus is highly reactive, catching fire spontaneously when exposed to air and requiring storage under water [1], red phosphorus does not ignite spontaneously in air. It possesses a polymeric structure consisting of long chains of phosphorus atoms, which contributes to its increased stability and higher melting point compared to the discrete P4 molecules of white phosphorus. Furthermore, red phosphorus does not exhibit phosphorescence; that property is characteristic of white phosphorus, which glows due to chemiluminescence upon oxidation. Although red phosphorus can be converted back to white phosphorus by careful heating, its safety in matches is derived from its relative inertness under normal conditions.

Sources

1. [1] Science-Class VII . NCERT(Revised ed 2025) > Chapter 4: The World of Metals and Non-metals > Activity 4.8: Let us explore > p. 53