text: The white allotrope can be produced using several methods. In the industrial process, phosphate rock is heated in an electric or fuel-fired furnace in the presence of carbon and silica. Elemental phosphorus is then liberated as a vapour and can be collected under phosphoric acid. An idealized equation for this carbothermal reaction is shown for calcium phosphate (although phosphate rock contains substantial amounts of fluoroapatite):
  White phosphorus has an appreciable vapour pressure at ordinary temperatures. The vapour density indicates that the vapour is composed of  molecules up to about 800 °C. Above that temperature, dissociation into diphosphorus| molecules occurs.
  In base, white phosphorus spontaneously disproportionates to phosphine and various phosphorus oxyacids.   
  It ignites spontaneously in air at about , and at much lower temperatures if finely divided (due to melting-point depression). Phosphorus reacts with oxygen, usually forming two oxides depending on the amount of available oxygen:  (phosphorus trioxide) when reacted with a limited supply of oxygen, and  when reacted with excess oxygen. On rare occasions, , , and  are also formed, but in small amounts. This combustion gives phosphorus(V) oxide:
  Because of this property, white phosphorus is used as a weapon.
  Phosphorus pentachloride is prepared by the reaction of white phosphorus with excess of dry chlorine.
  It can also be prepared by the action of sulfuryl chloride on white phosphorus.