Cyanogen chloride

Cyanogen chloride

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Cyanogen chloride is an inorganic compound
Inorganic compound
Inorganic compounds have traditionally been considered to be of inanimate, non-biological origin. In contrast, organic compounds have an explicit biological origin. However, over the past century, the classification of inorganic vs organic compounds has become less important to scientists,...

 with the formula
Chemical formula
A chemical formula or molecular formula is a way of expressing information about the atoms that constitute a particular chemical compound....

 NCCl. This linear, triatomic pseudohalogen
Pseudo'halogen molecules are inorganic molecules of the general formsPs–Ps or Ps–X, where Ps is a pseudohalogen group such as cyanide, cyanate, thiocyanate and others, and X is a "true" halogen...

 is an easily condensed colorless gas. More commonly encountered in the laboratory is the related compound cyanogen bromide
Cyanogen bromide
Cyanogen bromide is a pseudohalogen compound with the formula CNBr. It is a colorless solid that is widely used to modify biopolymers, fragment proteins and peptides, and synthesize other compounds.-Synthesis, basic properties, and structure:...

, a room-temperature solid that is widely used in biochemical analysis and preparation.

Synthesis, basic properties, structure

Although the formula is written CNCl, 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
Triple bond
A triple bond in chemistry is a chemical bond between two chemical elements involving six bonding electrons instead of the usual two in a covalent single bond. The most common triple bond, that between two carbon atoms, can be found in alkynes. Other functional groups containing a triple bond are...

. It is a linear molecule, as are the related cyanogen halides (NCF, NCBr
Cyanogen bromide
Cyanogen bromide is a pseudohalogen compound with the formula CNBr. It is a colorless solid that is widely used to modify biopolymers, fragment proteins and peptides, and synthesize other compounds.-Synthesis, basic properties, and structure:...

, NCI). Cyanogen chloride is produced by the oxidation of sodium cyanide
Sodium cyanide
Sodium cyanide is an inorganic compound with the formula NaCN. This highly toxic colorless salt is used mainly in gold mining but has other niche applications...

 with chlorine
Chlorine is the chemical element with atomic number 17 and symbol Cl. It is the second lightest halogen, found in the periodic table in group 17. The element forms diatomic molecules under standard conditions, called dichlorine...

. This reaction proceeds via the intermediate cyanogen
Cyanogen is the chemical compound with the formula 2. It is a colorless, toxic gas with a pungent odor.The molecule is a pseudohalogen. Cyanogen molecules consist of two CN groups — analogous to diatomic halogen molecules, such as Cl2, but far less oxidizing...

NaCN + Cl2 → ClCN + NaCl

The compound trimer
Trimer might refer to:* Trimer , a reaction product composed of three identical molecules* Protein trimer, a compound of three macromolecules non-covalently bound* Trimer, Ille-et-Vilaine, a commune in France-See also:...

izes in the presence of acid to the heterocycle called cyanuric chloride
Cyanuric chloride
Cyanuric chloride is the inorganic compound with the formula 3. This colorless solid is the chlorinated derivative of 1,3,5-triazine. It is the trimer of cyanogen chloride...


Cyanogen chloride is slowly hydrolyzed by water to release hydrogen cyanide
ClCN + H2O → HCN + HOCl

Applications in synthesis

Cyanogen chloride is a precursor to the sulfonyl cyanides and chlorosulfonyl isocyanate
Chlorosulfonyl isocyanate
Chlorosulfonyl isocyanate is the chemical compound ClSO2NCO, known as CSI. This compound is a versatile reagent in organic synthesis.-Preparation, structure, handling:...

, a useful reagent in organic synthesis
Organic synthesis
Organic synthesis is a special branch of chemical synthesis and is concerned with the construction of organic compounds via organic reactions. Organic molecules can often contain a higher level of complexity compared to purely inorganic compounds, so the synthesis of organic compounds has...



Also known as CK, cyanogen chloride is a highly toxic blood agent
Blood agent
A blood agent is a toxic chemical agent that affects the body by being absorbed into the blood. They are fast-acting, potentially lethal poisons that typically manifest at room temperature as volatile colorless gases with a faint odor. Blood agents are either cyanide- or...

, and was once proposed for use in chemical warfare
Chemical warfare
Chemical warfare involves using the toxic properties of chemical substances as weapons. This type of warfare is distinct from Nuclear warfare and Biological warfare, which together make up NBC, the military acronym for Nuclear, Biological, and Chemical...

. It causes immediate injury upon contact with the eyes or respiratory organs. Symptoms of exposure may include drowsiness, rhinorrhea
Rhinorrhea or rhinorrhoea is a condition where the nasal cavity is filled with a significant amount of mucous fluid. The condition, commonly known as "runny nose", occurs relatively frequently and is not usually considered dangerous. Rhinorrhea is a common symptom of allergies or certain diseases,...

 (runny nose), sore throat
Sore throat
A sore throat or throat pain is a common physical symptom usually caused by acute pharyngitis, or throat inflammation, though it also occurs in a number of other situations, such as post trauma and in diphtheria. It can cause mild to extreme pain....

, cough
A cough is a sudden and often repetitively occurring reflex which helps to clear the large breathing passages from secretions, irritants, foreign particles and microbes...

ing, confusion
ConFusion is an annual science fiction convention organized by the Stilyagi Air Corps and its parent organization, the Ann Arbor Science Fiction Association. Commonly, it is held the third weekend of January. It is the oldest science fiction convention in Michigan, a regional, general SF con...

, nausea
Nausea , is a sensation of unease and discomfort in the upper stomach with an involuntary urge to vomit. It often, but not always, precedes vomiting...

, vomiting
Vomiting is the forceful expulsion of the contents of one's stomach through the mouth and sometimes the nose...

, edema
Edema or oedema ; both words from the Greek , oídēma "swelling"), formerly known as dropsy or hydropsy, is an abnormal accumulation of fluid beneath the skin or in one or more cavities of the body that produces swelling...

, loss of consciousness, convulsion
A convulsion is a medical condition where body muscles contract and relax rapidly and repeatedly, resulting in an uncontrolled shaking of the body. Because a convulsion is often a symptom of an epileptic seizure, the term convulsion is sometimes used as a synonym for seizure...

s, paralysis
Paralysis is loss of muscle function for one or more muscles. Paralysis can be accompanied by a loss of feeling in the affected area if there is sensory damage as well as motor. A study conducted by the Christopher & Dana Reeve Foundation, suggests that about 1 in 50 people have been diagnosed...

, and death. It is especially dangerous because it is capable of penetrating the filters in gas mask
Gas mask
A gas mask is a mask put on over the face to protect the wearer from inhaling airborne pollutants and toxic gases. The mask forms a sealed cover over the nose and mouth, but may also cover the eyes and other vulnerable soft tissues of the face. Some gas masks are also respirators, though the word...

s, according to U.S.
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 analysts. CK is unstable due to polymerization
In polymer chemistry, polymerization is a process of reacting monomer molecules together in a chemical reaction to form three-dimensional networks or polymer chains...

, sometimes with explosive violence.

Cyanogen chloride is listed in schedule 3 of the Chemical Weapons Convention
Chemical Weapons Convention
The Chemical Weapons Convention is an arms control agreement which outlaws the production, stockpiling and use of chemical weapons. Its full name is the Convention on the Prohibition of the Development, Production, Stockpiling and Use of Chemical Weapons and on their Destruction...

: all production must be reported to the OPCW.

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