Cyanogen iodide or iodine cyanide (ICN) is a pseudohalogen composed of iodine and the cyanide group. It is a highly toxic inorganic compound. It occurs as white crystals that react slowly with water to form hydrogen cyanide.[5][6][7]
Cyanogen iodide has been used in taxidermy as a preservative[8][9] because of its toxicity.[9]
History
Cyanogen iodide was first synthesized in 1824 by the French chemist Georges-Simon Serullas (1774–1832).[10]
Cyanogen iodide was considered one of the impurities in commercially sold iodine before the 1930s.[citation needed]
Hazards
Cyanogen iodide is toxic if inhaled or ingested and may be fatal if swallowed or absorbed through the skin. Cyanogen iodide may cause convulsions, paralysis and death from respiratory failure. It is a strong irritant and may cause burns to the eyes and skin if contacted. If cyanogen iodide is heated enough to undergo complete decomposition, it may releases toxic fumes of nitrogen oxides, cyanide and iodide. A fire may cause the release of poisonous gas. Cyanogen iodide decomposes when contacted with acids, bases, ammonia, alcohols, and with heating. ICN slowly reacts with water or carbon dioxide to produce hydrogen cyanide.[9][11][12][13]
Cyanogen iodide solutions in pyridine conduct electric current. Dilute solutions of ICN in pyridine are colorless at first, but upon standing become successively yellow, orange, red-brown and deep red-brown. This effect is due to a change in conductivity, which in turn is due to the formation of an electrolyte. When electrical conductivity of ICN is compared with that of iodine-pyridine solutions, the formation of the electrolyte in ICN proceeds much more slowly. Results confirm that cyanides are much weaker salts in pyridine than are iodides, although cyanogen iodide solutions are able to be dissolved in pyridine giving solutions with electrical conductivity that increases over time and results in maximum values.[15]
^Cyanogen Iodide in Linstrom, Peter J.; Mallard, William G. (eds.); NIST Chemistry WebBook, NIST Standard Reference Database Number 69, National Institute of Standards and Technology, Gaithersburg (MD) (retrieved 2022-09-16)
^"Cyanogen halide". Encyclopædia Britannica (online). Encyclopædia Britannica Inc. 2012. Retrieved 2012-04-12.
^ abcPohanish, R. P. (2011). "Cyanogen iodide". Sittig's Handbook of Toxic and Hazardous Chemicals and Carcinogens (6th ed.). Elsevier. p. 808. ISBN978-1-4377-7869-4.
^Audrieth, L. F.; Birr, E. J. (1933). "Anomalous Electrolytes. I. The Electrical Conductivity of Solutions of Iodine and Cyanogen Iodide in Pyridine". Journal of the American Chemical Society. 55 (2): 668–673. doi:10.1021/ja01329a030.