Red phosphorus

[7] Due to such a kinetic stability, red phosphorus doesn't spontaneously ignite in air.

It doesn't disproportionate in the presence of alkali, and is less reactive towards halogens, sulfur, and metals compared with white phosphorus.

Its mechanism of action involves the formation of polyphosphoric acid (the hydrogen atoms are from the resin) and char, which prevents flame propagation.

[8] However, for electronic/electrical systems, red phosphorus flame retardant has been effectively banned by major OEMs due to its tendency to induce premature failures.

[9] One persistent problem is that red phosphorus in epoxy molding compounds induces elevated leakage current in semiconductor devices.

[11] Red phosphorus is used, along with abrasives, on the strike pads of modern safety matches.

The match head, containing potassium chlorate, will ignite upon friction with the strike pad.

This reaction is notable in the illicit production of methamphetamine and Krokodil, where hydrogen iodide acts as a reducing agent.

[citation needed] The reaction of red phosphorus and bromine alone does not generate a flame.

NFPA 704 four-colored diamond Health 1: Exposure would cause irritation but only minor residual injury. E.g. turpentine Flammability 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g. canola oil Instability 1: Normally stable, but can become unstable at elevated temperatures and pressures. E.g. calcium Special hazards (white): no code
Red phosphorus chain fragment for interchain connection
Red phosphorus chain fragment
Hittorf's phosphorus chain structure
Hitorff's phosphorus crystal structure
Fibrous red phosphorus structure