organic chemistry Organic chemistry is a subdiscipline within chemistry involving the science, scientific study of the structure, properties, and reactions of organic compounds and organic matter, organic materials, i.e., matter in its various forms that contain ...

, cyanocarbons are a group of

chemical compound A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element ...

s that contain several cyanide

functional group In organic chemistry, a functional group is any substituent or moiety (chemistry), moiety in a molecule that causes the molecule's characteristic chemical reactions. The same functional group will undergo the same or similar chemical reactions r ...

s. Such substances generally are classified as

organic compound Some chemical authorities define an organic compound as a chemical compound that contains a carbon–hydrogen or carbon–carbon bond; others consider an organic compound to be any chemical compound that contains carbon. For example, carbon-co ...

s, since they are formally derived from

hydrocarbon In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons are examples of group 14 hydrides. Hydrocarbons are generally colourless and Hydrophobe, hydrophobic; their odor is usually fain ...

s by replacing one or more

hydrogen Hydrogen is a chemical element; it has chemical symbol, symbol H and atomic number 1. It is the lightest and abundance of the chemical elements, most abundant chemical element in the universe, constituting about 75% of all baryon, normal matter ...

atoms with a

cyanide In chemistry, cyanide () is an inorganic chemical compound that contains a functional group. This group, known as the cyano group, consists of a carbon atom triple-bonded to a nitrogen atom. Ionic cyanides contain the cyanide anion . This a ...

group.Webster, Owen W. "Cyanocarbons: a classic example of discovery-driven research" Journal of Polymer Science, Part A: Polymer Chemistry 2001, volume, 40, pp. 210-221. One of the simplest member is (

tetracyanomethane Tetracyanomethane or carbon tetracyanide is an organic compound with the chemical formula . It is a percyanoalkane. It is a molecular carbon nitride. The structure can be considered as methane with all hydrogen atoms replaced by cyanide groups. ...

, also known as carbon tetracyanide). Organic chemists often refer to cyanides as

nitrile In organic chemistry, a nitrile is any organic compound that has a functional group. The name of the compound is composed of a base, which includes the carbon of the , suffixed with "nitrile", so for example is called " propionitrile" (or pr ...

s. In general, cyanide is an

electronegative Electronegativity, symbolized as , is the tendency for an atom of a given chemical element to attract shared electrons (or electron density) when forming a chemical bond. An atom's electronegativity is affected by both its atomic number and the d ...

substituent. Thus, for example, cyanide-substituted

carboxylic acid In organic chemistry, a carboxylic acid is an organic acid that contains a carboxyl group () attached to an Substituent, R-group. The general formula of a carboxylic acid is often written as or , sometimes as with R referring to an organyl ...

s tend to be stronger than the parents. The cyanide group can also stabilize anions by delocalizing negative

charge Charge or charged may refer to: Arts, entertainment, and media Films * ''Charge, Zero Emissions/Maximum Speed'', a 2011 documentary Music * ''Charge'' (David Ford album) * ''Charge'' (Machel Montano album) * '' Charge!!'', an album by The Aqu ...

as revealed by

resonance Resonance is a phenomenon that occurs when an object or system is subjected to an external force or vibration whose frequency matches a resonant frequency (or resonance frequency) of the system, defined as a frequency that generates a maximu ...

structures.

Definition and examples

''Cyanocarbons are organic compounds bearing enough cyano functional groups to significantly alter their chemical properties.'' Illustrative cyanocarbons: *

Tetracyanoethylene Tetracyanoethylene (TCNE) is organic compound with the formula . It is a colorless solid, although samples are often off-white. It is an important member of the cyanocarbons. Synthesis and reactions TCNE is prepared by brominating malononitril ...

, which reduces to a stable anion ₂(CN)₄sup>−, unlike most derivatives of

ethylene Ethylene (IUPAC name: ethene) is a hydrocarbon which has the formula or . It is a colourless, flammable gas with a faint "sweet and musky" odour when pure. It is the simplest alkene (a hydrocarbon with carbon–carbon bond, carbon–carbon doub ...

. * Pentacyanocyclopentadiene, which forms an air-stable anion, in contrast to

cyclopentadiene Cyclopentadiene is an organic compound with the chemical formula, formula C5H6. It is often abbreviated CpH because the cyclopentadienyl anion is abbreviated Cp−. This colorless liquid has a strong and unpleasant odor. At room temperature, ...

. * Tetracyanoethylene oxide, an electrophilic

epoxide In organic chemistry, an epoxide is a cyclic ether, where the ether forms a three-atom ring: two atoms of carbon and one atom of oxygen. This triangular structure has substantial ring strain, making epoxides highly reactive, more so than other ...

that undergoes ready scission of its C-C bond. *

Tetracyanoquinodimethane Tetracyanoquinodimethane (TCNQ) is an organic compound with the chemical formula . It is an orange crystalline solid. This cyanocarbon, a relative of para-quinone, is an electron acceptor that is used to prepare charge transfer salts, which ar ...

, , which reduces to a stable anion, unlike most

quinone The quinones are a class of organic compounds that are formally "derived from aromatic compounds benzene.html" ;"title="uch as benzene">uch as benzene or naphthalene] by conversion of an even number of –CH= groups into –C(=O)– groups with ...

s. * Cyanoform (tricyanomethane), * Pentacyanopropenide, .

References

Nitriles {{organic-compound-stub