Cyanogen iodide

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Cyanogen iodide
Skeletal formula of cyanogen iodide
Ball and stick model of cyanogen iodide
Spacefill model of cyanogen iodide
IUPAC name
Carbononitridic iodide[2]
Systematic IUPAC name
Iodoformonitrile[citation needed]
Other names
Iodine cyanide[1]
3D model (Jmol)
ECHA InfoCard 100.007.322
EC Number 208-053-3
RTECS number NN1750000
Molar mass 152.9219 g mol−1
Appearance White crystals
Density 1.84 g mL−1
Melting point 146.7 °C (296.1 °F; 419.8 K)
160.5–169.1 kJ mol−1
NFPA 704
Flammability code 0: Will not burn. E.g., water Health code 3: Short exposure could cause serious temporary or residual injury. E.g., chlorine gas Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
Related compounds
Related alkanenitriles
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Cyanogen iodide or iodine cyanide (ICN) is a pseudohalogen composed of iodine and the cyanide group. It is a relatively volatile and highly toxic inorganic compound. It occurs as white crystals that react slowly with water to form hydrogen cyanide.[4][5][6]


Cyanogen iodide is prepared by combining I2 and a cyanide, most commonly sodium cyanide in ice-cold water. The product is extracted with ether.[4][5][6]

I2 + NaCN → NaI + ICN


Cyanogen iodide has been used in taxidermy as a preservative.[7][8] Generally, cyanogen iodide is used for destroying all lower forms of life.[8]


Cyanogen iodide was considered one of the impurities in commercially sold iodine before the 1930s.[citation needed]


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 contact is encountered. 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.[8][9][10][11]

It is classified as an extremely hazardous substance in the United States as defined in Section 302 of the U.S. Emergency Planning and Community Right-to-Know Act (42 U.S.C. 11002), and is subject to strict reporting requirements by facilities which produce, store, or use it in significant quantities.[12]

Solutions in pyridine[edit]

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.[13]

External links[edit]


  1. ^ The Merck Index (10th ed.). Rahway, NJ: Merck & Co. 1983. p. 385. 
  2. ^ "Iodine cyanide - Compound Summary". PubChem Compound. USA: National Center for Biotechnology Information. 27 March 2005. Identification. Retrieved 4 June 2012. 
  3. ^ Lide, David R., ed. (2006). CRC Handbook of Chemistry and Physics (87th ed.). Boca Raton, FL: CRC Press. ISBN 0-8493-0487-3. 
  4. ^ a b Bak, B.; Hillebert, A. (1952). "CYANOGEN IODIDE". Org. Synth. 32: 29. ; Coll. Vol., 4, p. 207 
  5. ^ a b Langlois, M. (1860). "CYANOGÈNE Action de l'iode sur une solution concentrée de cyanure de potassium". Comptes Rendus. 51: 29. 
  6. ^ a b Langlois, M. (1860). "Ueber die Einwirkung des Jods auf concentrirte Cyankaliumlösung". Annalen der Chemie und Pharmacie. 116 (3): 288. doi:10.1002/jlac.18601160303. 
  7. ^ "Cyanogen halide". Encyclopædia Britannica (online). Encyclopædia Britannica Inc. 2012. Retrieved 2012-04-12. 
  8. ^ a b c Pohanish, R. P. (2011). "Cyanogen iodide". Sittig’s Handbook of Toxic and Hazardous Chemicals and Carcinogens (6th ed.). Elsevier. p. 808. ISBN 978-1-4377-7869-4. 
  9. ^ "Iodine cyanide - Compound Summary (CID 10478)". PubChem. NIH. 
  10. ^ "Iodine Cyanide; International Chemical Safety Card No. 0662 (U.S. National Version)". National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention. 2005. Retrieved 2012-04-12. 
  11. ^ "Cyanogen Iodide". ChemicalBook. 
  12. ^ "40 C.F.R.: Appendix A to Part 355—The List of Extremely Hazardous Substances and Their Threshold Planning Quantities" (PDF) (July 1, 2008 ed.). Government Printing Office. Retrieved October 29, 2011. 
  13. ^ 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.