Question

Why red phosphorus is used in safety matches?

Answer 1

Red phosphorus:

• Red phosphorus is a typical allotrope of phosphorus.
• It is made up of phosphorus atoms in an amorphous (non-crystalline) network.
• It has been discovered to be more persistent than white phosphorus (another naturally occurring phosphorus allotrope).

Red phosphorus is used in safety matches:

• The friction between the match and the striking surface causes the match to heat up.
• On the friction surface, a small amount of red phosphorus is transformed into white phosphorus.
• Red phosphorus has a low ignition temperature. Thus, it is used in the manufacturing of safety matches.

Red phosphorus is preferred over white phosphorus in the manufacture of matches:

• Because of its tetrahedral structure, which has a substantially less angular strain, red $\mathrm{P}$ is favored over white $\mathrm{P}$.
• Furthermore, white $\mathrm{P}$ is poisonous, whereas red $\mathrm{P}$ is not.