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 materials, i.e., matter in its various forms that contain carbon atoms.Clay ...

, 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 ele ...

s that contain several cyanide

functional group In organic chemistry, a functional group is a substituent or moiety in a molecule that causes the molecule's characteristic chemical reactions. The same functional group will undergo the same or similar chemical reactions regardless of the res ...

s. Such substances generally are classified as

organic compound In chemistry, organic compounds are generally any chemical compounds that contain carbon- hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. Th ...

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 hydrophobic, and their odors are usually weak or ...

s by replacing one or more

hydrogen Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic ...

atoms with a

cyanide Cyanide is a naturally occurring, rapidly acting, toxic chemical that can exist in many different forms. In chemistry, a cyanide () is a chemical compound that contains a functional group. This group, known as the cyano group, consists of ...

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. The parent member is (

tetracyanomethane Tetracyanomethane or carbon tetracyanide is a percyanoalkane molecular carbon nitride with formula C(CN)4. The structure can be considered as methane with all hydrogen atoms replaced by cyanide groups. It was first made by Erwin Mayer in 1969. P ...

, 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 prefix '' cyano-'' is used interchangeably with the term ''nitrile'' in industrial literature. Nitriles are found in many useful compounds, including me ...

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 R-group. The general formula of a carboxylic acid is or , with R referring to the alkyl, alkenyl, aryl, or other group. Carboxyl ...

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

resonance Resonance describes the phenomenon of increased amplitude that occurs when the frequency of an applied periodic force (or a Fourier component of it) is equal or close to a natural frequency of the system on which it acts. When an oscillat ...

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 malononitri ...

, which reduces to a stable anion, 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 double bonds). Ethylene ...

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

cyclopentadiene Cyclopentadiene is an organic compound with the formula C5H6.LeRoy H. Scharpen and Victor W. Laurie (1965): "Structure of cyclopentadiene". ''The Journal of Chemical Physics'', volume 43, issue 8, pages 2765-2766. It is often abbreviated CpH beca ...

. * Tetracyanoethylene oxide, an electrophilic

epoxide In organic chemistry, an epoxide is a cyclic ether () with a three-atom ring. This ring approximates an equilateral triangle, which makes it strained, and hence highly reactive, more so than other ethers. They are produced on a large scale ...

that undergoes ready scission of its C-C bond. * Tetracyanoquinodimethane, C₆H₄-1,4-(C(CN)₂)₂, 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), (NC)₃CH * Pentacyanopropenide, NC)₂C-C(CN)-C(CN)₂sup>−.

References

Nitriles {{Chemistry-stub