Application areas of white phosphorus

White phosphorus, though dangerous, has many uses. In industry, white phosphorus is used to prepare high-purity phosphoric acid. White phosphorus is flammable to produce smoke (P4O10) and fog (P4O10 and water vapor to form H3PO4 and other foggy substances), and is commonly used in the military to make smoke bombs and incendiary bombs. White phosphorus can also be used to make red phosphorus (red phosphorus), tetraphosphorus trisulfide (P4S3), organophosphate, incendiary bombs, rodenticides and so on.

Yellow phosphorus, also called white phosphorus, is a white to light yellow brittle waxy solid with a melting point of 44.1°C, a boiling point of 280°C, and a density of 1.82 g/cm3;. White phosphorus is very active, must be stored in water, people inhale 0.1 grams of white phosphorus will be poisoned to death. White phosphorus is converted to red phosphorus when heated to 260°C or under light in the absence of air. Red phosphorus is non-toxic and does not catch fire until heated to 240°C or more. Under high pressure, white phosphorus can be transformed into black phosphorus, which has a layered network structure, conducts electricity, and is the most stable of the phosphorus isomers.

If there is insufficient oxygen, white phosphorus oxidizes very slowly under humid conditions and is accompanied by the phenomenon of phosphorescence. White phosphorus is soluble in hot concentrated alkali solutions to form phosphine and dihydrogen phosphite; dry chlorine gas reacts with excess phosphorus to form phosphorus trichloride, and excess chlorine gas reacts with phosphorus to form phosphorus pentachloride. Phosphorus burns in sufficient air to produce phosphorus pentoxide, and if there is insufficient air it produces phosphorus trioxide.

White phosphorus reacts with hot concentrated lye Chemical formula:

P4 + 3KOH(concentrated) + 3H2O→ PH3↑ + 3KH2PO2.

Old incandescent bulbs are coated with a bit of red phosphorus on the sensory column. Red phosphorus heat will become white phosphorus, white phosphorus is easy to react with oxygen to generate solid phosphorus pentoxide (chemical equation: 4P + 5O2 == 2P2O5), the oxygen "eat", so that the residual oxygen in the glass shell is also eliminated. Prevent the tungsten filament after powering up the temperature rises to 2000 ℃ or more, resulting in quickly burned off.