Hydrogen cyanide (HCN), sometimes alleged prussic acid, is an amoebic admixture with the actinic blueprint HCN. It is a colorless, acutely poisonous and combustible aqueous that boils hardly aloft allowance temperature, at 25.6 °C (78.1 °F). HCN is produced on an automated calibration and is a awful admired forerunner to abounding actinic compounds alignment from polymers to pharmaceuticals.

Hydrogen cyanide is a beeline molecule, with a amateur band amid carbon and nitrogen. A accessory tautomer of HCN is HNC, hydrogen isocyanide.

Hydrogen cyanide is abominably acerb with a pKa of 9.2. It partially ionizes in baptize band-aid to accord the cyanide anion, CN−. A band-aid of hydrogen cyanide in water, represented as HCN, is alleged hydrocyanic acid. The salts of the cyanide anion are accepted as cyanides.

HCN has a aside absinthian almond-like odor that some humans are clumsy to ascertain attributable to a abiogenetic trait.The airy admixture has been acclimated as assimilation rodenticide and animal poison, as able-bodied as for killing whales. Cyanide ions baffle with iron-containing respiratory enzymes.