 The striking surface on modern matchboxes is typically composed of 25% powdered glass or other abrasive material, 50% red phosphorus, 5% neutralizer, 4% carbon black, and 16% binder; and the match head is typically composed of 45–55% potassium chlorate, with a little sulfur and starch, a neutralizer (ZnO or ), 20–40% of siliceous filler, diatomite, and glue.Some heads contain antimony(III) sulfide to make them burn more vigorously.Safety matches ignite due to the extreme reactivity of phosphorus with the potassium chlorate in the match head.