White phosphorus

White phosphorus,also known as yellow phosphorus, is a nonmetallic element that is found in the form of crystals or a wax-like transparent solid. It ignites spontaneously in air at 86°F, which is also its ignition temperature. White phosphorus should be stored under water and away from heat. It is a dangerous fire risk, with a boiling point of 536°F (280°C) and a melting point of 111°F (43°C). White phosphorus is toxic by inhalation and ingestion, and contact with skin produces burns. The TLV is 0.1 mg/m3 of air, and it is insoluble in water, with a specific gravity of 1.82, which is heavier than air. White phosphorus is shipped and stored under water to keep it from contacting air. The four-digit UN identification number is 2447. The NFPA 704 designation is health 4, flammability 4, and reactivity 2. The primary uses are in rodenticides, smoke screens, and analytical chemistry.