Picric Acid

When wetted with not less than 10 percent water by mass, picric acid is a yellow mass of moist crystals or a slurry. It is dangerously explosive if allowed to dry out, but wetting reduces the risk of detonation. Picric acid is used in the synthesis of dyes, to manufacture matches and explosives, to make colored glass, to etch copper, and as a drug. The main reason for the decline of picric acid usage has been its toxic nature.