Cyanide (redirected from Cyadine)

cyanide (sī`ənīd'), chemical compound containing the cyano group, -CN. Cyanides are salts or esters of hydrogen cyanide (hydrocyanic acid, HCN) formed by replacing the hydrogen with a metal (e.g., sodium or potassium) or a radical (e.g., ammonium or ethyl). The most common and widely used cyanides are those of sodium and potassium; they are often referred to simply as "cyanide." Both are white, crystalline, chemically active compounds. They are used as insecticides, in making pigments, in metallurgy (e.g., electroplating and case hardening), and in refining gold and silver by the cyanide process. Organic cyanides are called nitriles. The ethyl ester of hydrogen cyanide (CH₃CH₂CN) is called variously ethyl cyanide, propionitrile, propane nitrile, nitrilopropane, and cyanoethane; propane nitrile is the approved name in the nomenclature system for organic chemistry adopted by the International Union of Pure and Applied Chemistry (IUPAC). Most cyanides are deadly poisons that cause respiratory failure. Symptoms of cyanide poisoning include an odor of bitter almond on the breath, dizziness, convulsions, collapse, and, often, froth on the mouth. In case of cyanide poisoning a doctor should be summoned immediately. If the poison was swallowed, vomiting should be induced. Artificial respiration should be used if needed.

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cyanide

Any chemical compound containing the combining group CN. Ionic (see ion; ionic bond) and organic cyanide compounds differ in chemical properties, but both are toxic, especially the ionic ones. Cyanide poisoning inhibits cells' oxidative (see oxidation-reduction) processes; its action is extremely rapid, and an antidote must be given promptly. Cyanides occur naturally in certain seeds (e.g., apple seeds, wild cherry pits). Cyanides, including hydrogen cyanide (HCN, or hydrocyanic acid), are used industrially in the production of acrylic fibres, synthetic rubbers, and plastics as well as in electroplating, case-hardening of iron and steel, fumigation, and concentration of ores.

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cyanide, cyanid

1. any salt of hydrocyanic acid. Cyanides contain the ion CN^-- and are extremely poisonous

2. another name (not in technical usage) for nitrile

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cyanide [′sī·ə‚nīd]

(inorganic chemistry)

Any of a group of compounds containing the CN group and derived from hydrogen cyanide, HCN.

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Cyanide 

a salt of hydrocyanic acid. The cyanide salts of the alkali metals MCN and the alkaline-earth metals M(CN)₂, where M is a metal, are thermally stable but are hydrolyzed in aqueous solutions. The cyanides of the heavy metals are thermally unstable and, with the exception of Hg(CN)₂, are insoluble in water.

The oxidation of cyanides leads to the formation of cyanates; for example, 2KCN + O₂ → 2KOCN. Many metals upon the action of an excess of potassium cyanide or sodium cyanide yield complexes. This proves useful in the extraction of gold and silver from ores (cyanidation, cyanide process):

4NaCN + 2Au + ½O₂ + H₂O → 2Na[ Au(CN)₂] + 2NaOH

Gold and silver are separated from solution by electrodeposition or by the action of metallic zinc. Solutions of the cyanide complexes of gold, silver, zinc, and other metals are used in electroplating technology for the production of coatings. Cyanides are also used in organic synthesis, for example, in the production of nitriles, and as catalysts (in benzoin condensation).

Cyanides are extremely toxic. (For information on the effect of cyanides on the organism and on safety measures when handling them, seeHYDROCYANIC ACID.)

REFERENCES

Bobkov, S. S., and S. K. Smirnov. Sinil’naia kislota. Moscow, 1970.
Zil’berman, E. N. Reaktsii nitrilov. Moscow, 1972.
Tomilov, A. P., and S. K. Smirnov. Adipodinitril i geksamet ilendiamin. Moscow, 1974.
Williams, H. E. Cyanogen Compounds, 2nd ed. London, 1948.
Migrdichian, V. The Chemistry of Organic Cyanogen Compounds. New York, 1947.
Methoden der Organischen Chemie (Houben-Weyl), 4th ed., vol. 8. Stuttgart, 1952.

S. K. SMIRNOV