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The phosphorus used in the manufacture of safety matches is
Explanation
Red phosphorus is the specific allotrope used in the manufacture of modern safety matches. Historically, white phosphorus was used in 'strike-anywhere' matches, but it was phased out due to its extreme toxicity and high reactivity, as it can self-ignite in air at temperatures as low as 40°C. In contrast, red phosphorus is non-toxic and significantly more stable, with an ignition point above 200°C. In a safety match system, the red phosphorus is typically located on the striking surface of the matchbox rather than the match head itself. When the match is struck, friction converts a small amount of red phosphorus into white phosphorus, which then ignites and sets off the combustion of the match head chemicals, such as potassium chlorate.