Fulminic acid is a chemical compound with a molecular formula HCNO. Its silver salt was discovered in 1800 by Edward Charles Howard and later investigated in 1824 by Justus von Liebig. It is an organic acid and an isomer of isocyanic acid, the silver salt of which was discovered one year later by Friedrich Woehler. The free acid was first isolated in 1966
Fulminic acid and its salts (fulminates), for instance mercury fulminate, are very dangerous, and are often used as detonators for other explosive materials, and are examples of primary explosives. The vapors also are toxic.