Cyanogen chloride

From Wikipedia, the free encyclopedia
  (Redirected from ClCN)
Jump to: navigation, search
Cyanogen chloride
Skeletal formula of cyanogen chloride
Ball and stick model of cyanogen chloride
Spacefill model of cyanogen chloride
Preferred IUPAC name
Carbononitridic chloride
Systematic IUPAC name
Other names
  • Chlorine cyanide
  • Cyanic chloride
  • Chlorocyanogen
  • Chlorcyan
  • Chlorocyanide
3D model (Jmol)
Abbreviations CK
ECHA InfoCard 100.007.321
EC Number 208-052-8
MeSH cyanogen+chloride
RTECS number GT2275000
UN number 1589
Molar mass 61.470 g mol−1
Appearance Colorless gas
Odor acrid
Density 2.7683 mg mL−1 (at 0 °C, 101.325 kPa)
Melting point −6.55 °C (20.21 °F; 266.60 K)
Boiling point 13 °C (55 °F; 286 K)
Solubility soluble in ethanol, ether
Vapor pressure 1.987 MPa (at 21.1 °C)
-32.4·10−6 cm3/mol
236.33 J K−1 mol−1
137.95 kJ mol−1
Main hazards Highly toxic;[2] forms cyanide in the body[3]
Safety data sheet
NFPA 704
Flammability code 0: Will not burn. E.g., water Health code 4: Very short exposure could cause death or major residual injury. E.g., VX gas Reactivity code 2: Undergoes violent chemical change at elevated temperatures and pressures, reacts violently with water, or may form explosive mixtures with water. E.g., phosphorus Special hazards (white): no codeNFPA 704 four-colored diamond
Flash point nonflammable [3]
US health exposure limits (NIOSH):
PEL (Permissible)
REL (Recommended)
C 0.3 ppm (0.6 mg/m3)[3]
IDLH (Immediate danger)
Related compounds
Related alkanenitriles
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
YesY verify (what is YesYN ?)
Infobox references

Cyanogen chloride is an organic compound with the formula NCCl. This linear, triatomic pseudohalogen is an easily condensed colorless gas. More commonly encountered in the laboratory is the related compound cyanogen bromide, a room-temperature solid that is widely used in biochemical analysis and preparation.

Synthesis, basic properties, structure[edit]

Cyanogen chloride is a molecule with the connectivity ClCN. Carbon and chlorine are linked by a single bond, and carbon and nitrogen by a triple bond. It is a linear molecule, as are the related cyanogen halides (NCF, NCBr, NCI). Cyanogen chloride is produced by the oxidation of sodium cyanide with chlorine. This reaction proceeds via the intermediate cyanogen ((CN)2).[4]

NaCN + Cl2 → ClCN + NaCl

The compound trimerizes in the presence of acid to the heterocycle called cyanuric chloride.

Cyanogen chloride is slowly hydrolyzed by water to release cyanate and chloride ions

ClCN + H2O → NCO + Cl + 2H+
at neutral pH

Applications in synthesis[edit]

Cyanogen chloride is a precursor to the sulfonyl cyanides[5] and chlorosulfonyl isocyanate, a useful reagent in organic synthesis.[6]


Also known as CK, cyanogen chloride is a highly toxic blood agent, and was once proposed for use in chemical warfare. It causes immediate injury upon contact with the eyes or respiratory organs. Symptoms of exposure may include drowsiness, rhinorrhea (runny nose), sore throat, coughing, confusion, nausea, vomiting, edema, loss of consciousness, convulsions, paralysis, and death.[2] It is especially dangerous because it is capable of penetrating the filters in gas masks, according to U.S. analysts. CK is unstable due to polymerization, sometimes with explosive violence.[7]

Cyanogen chloride is listed in schedule 3 of the Chemical Weapons Convention: all production must be reported to the OPCW.[citation needed]


  1. ^ Lide, David R., ed. (2006). CRC Handbook of Chemistry and Physics (87th ed.). Boca Raton, FL: CRC Press. ISBN 0-8493-0487-3. 
  2. ^ a b "CYANOGEN CHLORIDE (CK)". The Emergency Response Safety and Health Database. NIOSH. 
  3. ^ a b c d e "NIOSH Pocket Guide to Chemical Hazards #0162". National Institute for Occupational Safety and Health (NIOSH). 
  4. ^ Coleman, G. H.; Leeper, R. W.; Schulze, C. C. (1946). "Cyanogen Chloride". Inorganic Syntheses. 2: 90–94. doi:10.1002/9780470132333.ch25. 
  5. ^ Vrijland, M. S. A. (1977). "Sulfonyl Cyanides: Methanesulfonyl Cyanide" (PDF). Org. Synth. 57: 88. ; Coll. Vol., 6, p. 727 
  6. ^ Graf, R. (1966). "Chlorosulfonyl Isocyanate" (PDF). Org. Synth. 46: 23. ; Coll. Vol., 5, p. 226 
  7. ^ FM 3-8 Chemical Reference Handbook. US Army. 1967. 

External links[edit]