Chemistry of the Safety Match
Safety matches are ‘safe’ because they don’t spontaneously combust. You have to strike them against a special surface in order to get them to ignite. The match heads contain sulfur (sometimes antimony III sulfide [Sb2S3]) and oxidizing agents (usually potassium chlorate [KClO3]), with powdered glass, colorants, fillers, and a binder made of glue and starch. The striking surface consists of powdered glass or silica (sand), red phosphorus, binder, and filler. When you strike a safety match, the glass-on-glass friction generates heat, converting a small amount of red phosphorus to white phosphorus vapor. The phosphorus and potassium chlorate mix in a small amount forming an explosive reaction which ignites due to the friction. The cloud of white smoke and the characteristic smell of burning matches is phosphorus pentoxide (P4O10).
When sulfur is burned, it melts to a blood-red liquid (top picture). At night (bottom picture) the flame is much more visible.