cianid

Cianid, or cyanide, denotes a family of chemical species containing the cyano group CN−. It appears as hydrogen cyanide (HCN) and as cyanide salts such as sodium cyanide (NaCN) and potassium cyanide (KCN). In aqueous solution, CN− and HCN are interconvertible depending on pH.

In nature, cyanide compounds occur in trace amounts in some plants and seeds. Cyanogenic glycosides released upon damage can release hydrogen cyanide, notably in cassava, bitter almonds, and lima beans. Cyanide is also present in trace amounts in some foods and in the environment.

Chemically, cyanide forms stable complexes with many metals, such as ferrocyanide and ferricyanide, enabling uses in electroplating and synthesis. Industrially, hydrogen cyanide is produced on a large scale by processes such as the Andrussow process, which converts methane and ammonia with oxygen over a catalyst. Cyanide salts are produced by acidifying HCN and forming salts with alkali metals or alkaline earth metals.

Uses include gold and silver mining by cyanide leaching, electroplating, organic synthesis, and the production of nitriles and polymers. Safety and toxicity are central concerns: cyanide inhibits mitochondrial cytochrome c oxidase, halting cellular respiration. Hydrogen cyanide gas is extremely toxic; exposure can occur by inhalation, ingestion, or skin contact. Acute treatments include antidotes such as hydroxocobalamin or nitrite-thiosulfate regimens; facility detoxification often employs chemical oxidation or alkaline chlorination before discharge.

Environmental management emphasizes minimizing releases, rapid detoxification of effluents, and adherence to regulatory limits to protect workers and ecosystems.