Cyanide is a a compound containing the carbon-nitrogen, or cyano, radical combined with a metal or another radical. Cyanides are salts of hydrocyanic (prussic) acid. The name "cyanide" is most commonly used for two compounds, potassium cyanide and sodium cyanide.
Most cyanides are poisonous, and some are used to kill insects and rodents. Calcium cyanide, for example, is an effective fumigant. Mixed with water, it gives off fumes of hydrocyanic acid that kill living cells by disrupting their oxidation processes.
Sodium and potassium cyanide are used in the cyanide process of extracting gold and silver from their ores. A solution of either cyanide dissolves gold or silver from ores. The metals are then precipitated with zinc. In electroplating, cyanides help to distribute metal evenly on the article being plated. Cyanides are also used in making various pigments, including Prussian blue and Turnbull's blue. Organic cyanide compounds are called nitriles, and many are used in the manufacture of synthetic fibers and rubber.
