Cyanide | Definition, Uses, & Effects - Encyclopedia Britannica

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External Websites

• United States Enviromental Protection Agency - Cyanide Compounds
• New York State - Department of Health - The Facts About Cyanides
• Centers for Disease Control and Prevention - Cyanide
• Australian Government - Department of Climate Change, Energy, the Environment andWater - Cyanide (inorganic) compounds
• Canada.ca - Cyanide (PDF)
• Johns Hopkins Center for Health Security - Cyanide
• IOPscience - Plasma Research Express - Cyanide recombination in electric arc furnace plasma (PDF)
• Stanford University - Environmental Health and Safety - Information on Cyanide Compounds
• National Center for Biotechnology Information - Cyanide Toxicity

cyanide chemical compound Ask Anything Homework Help Written and fact-checked by Britannica Editors Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree.... Britannica Editors Last updated Nov. 28, 2025 •History Britannica AI Ask Anything Homework Help Table of Contents Table of Contents Ask Anything

cyanide, any compound containing the monovalent combining group CN. In inorganic cyanides, such as sodium cyanide (NaCN), this group is present as the negatively charged cyanide ion; these compounds, which are regarded as salts of hydrocyanic acid, are highly toxic. Organic cyanides are usually called nitriles; in these, the CN group is linked by a covalent bond to a carbon-containing group, such as methyl (CH3) in methyl cyanide (acetonitrile).

Hydrocyanic acid, also known as hydrogen cyanide (HCN), is a highly volatile liquid. HCN is manufactured via the Andrussow process, in which methane, ammonia, and oxygen are combined with a platinum metal catalyst. The HCN product is used to prepare acrylonitrile, which is used in the production of acrylic fibres, synthetic rubber, and plastics. Cyanides are employed in a number of chemical processes, including fumigation, case hardening of iron and steel, electroplating, and the concentration of ores. In nature, substances that can be chemically converted into cyanide are present in certain seeds, such as the pit of the black cherry (Prunus serotina) and the seeds of apples (Malus domestica).

Related Topics: potassium cyanide hydrocyanic acid hydroisocyanic acid potassium ferricyanide cyanogen (Show more) On the Web: National Center for Biotechnology Information - Cyanide Toxicity (Nov. 28, 2025) (Show more) See all related content

Cyanide poisoning results from inhaling HCN or ingesting HCN salts. Cyanide acts with extreme rapidity, and thus the promptness with which an antidote, such as amyl nitrite, sodium nitrite, or sodium thiosulfate solution, is administered is critical to preventing death.

This article was most recently revised and updated by Kara Rogers.