hydrogen cyanide

American  

noun

1. a colorless poisonous gas, HCN, having a bitter almondlike odor: in aqueous solution it forms hydrocyanic acid.

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hydrogen cyanide British  

noun

1. Also called: hydrocyanic acid.  a colourless poisonous liquid with a faint odour of bitter almonds, usually made by a catalysed reaction between ammonia, oxygen, and methane. It forms prussic acid in aqueous solution and is used for making plastics and dyes and as a war gas. Formula: HCN

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hydrogen cyanide Scientific  

1. A colorless, flammable, extremely poisonous liquid. Salts derived from it have many industrial uses, such as hardening iron and steel, extracting metals from ores, electroplating metallic surfaces, and making acrylonitrile, from which acrylic fibers and plastics are produced. It is also used to make dyes and poisons. A solution of hydrogen cyanide in water forms a colorless acid called hydrocyanic acid. Chemical formula: HCN.

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Etymology

Origin of hydrogen cyanide

First recorded in 1880–85

Example Sentences

See Examples For:

hydrogen cyanide

The first flames would have reacted with the flammable materials to produce carbon monoxide and hydrogen cyanide, often known as the "toxic twins" of fire smoke, he explains.

From BBC ● Jul. 14, 2026

This toxic smoke can include carbon monoxide and hydrogen cyanide.

From BBC ● Mar. 16, 2026

In this reaction, hydrogen cyanide, ammonia, and aldehydes or ketones combine in liquid water.

From Science Daily ● Feb. 12, 2026

One of the main substances created in this way is hydrogen cyanide.

From Science Daily ● Oct. 17, 2025

The assay for "cyanide" should include the hydrogen cyanide with the rest.

From A Text-book of Assaying: For the Use of Those Connected with Mines. by Beringer, Cornelius