Styphnic acid (from Greek stryphnos 'astringent'), or 2,4,6-trinitro-1,3-benzenediol, is a yellow astringent acid that forms hexagonal crystals. It is used in the manufacture of dyes, pigments, inks, medicines, and explosives such as lead styphnate. It is itself a low sensitivity explosive, similar to picric acid, but explodes upon rapid heating. Styphnic acid (from Greek stryphnos 'astringent'), or 2,4,6-trinitro-1,3-benzenediol, is a yellow astringent acid that forms hexagonal crystals. It is used in the manufacture of dyes, pigments, inks, medicines, and explosives such as lead styphnate. It is itself a low sensitivity explosive, similar to picric acid, but explodes upon rapid heating. It may be prepared by the nitration of resorcinol with a mixture of nitric and sulfuric acid. This compound is an example of a trinitrophenol. Like picric acid, it is a moderately strong acid, capable of displacing carbon dioxide from solutions of sodium carbonate, for example.