-ene

ene reaction coupled with orbital interactions and the transition state

The suffix -ene is used in organic chemistry to form names of organic compounds where the -C=C- group has been attributed the highest priority according to the rules of organic nomenclature. ^{[1] [2]} Sometimes a number between hyphens is inserted before it to say that the double bond is between that atom and the atom with the next number up. This suffix comes from the end of the word ethylene, which is the simplest alkene. The final "-e" disappears if it comes before by a suffix that starts with a vowel, e.g. "-enal", which is a compound that contains both a -C=C- bond and an aldehyde functional group. If the other suffix starts with a consonant or "y", the final "-e" remains, e.g. "-enediyne" (which has the "-ene" suffix and also the "-yne" suffix, for a compound with a double bond and two triple bonds.)

Usage

A Greek number prefix before the "-ene" indicates how many double bonds there are in the compound, e.g. butadiene. ^[3] The suffix is defined from an ene reaction. ^[4]

The suffix "-ene" is also used in inorganic chemistry to indicate a one-atom thick two-dimensional layer of atoms, as in graphene, silicene, stanene, borophene, xenzophene, and germanene.

Etymology

The suffix -ene was originally a Greek name-forming element without its own meaning. Its was used early on in the names of ethylene and methylene, the later being an alcohol rather than an alkene. It was first abstracted a formal naming system for the alkenes by August Wilhelm von Hofmann in 1866, whose proposed a vowel system (-ane, -ene, ine, -one, -une) to denote hydrocarbons of increasing degrees of desaturation. ^{[5] [6]}

Despite graphene not being an alkene, Hanns-Peter Boehm and his colleagues used the -ene suffix because of graphene's aromatic, cyclic hydrocarbon structure. ^[7] Similar allotropes such as stanene and borophene, which are made of other elements, contain the suffix -ene in a manner analogous to graphene.

See also

• IUPAC nomenclature of organic chemistry

References

1. The Commission on the Nomenclature of Organic Chemistry (1971) [1958]. Nomenclature of Organic Chemistry (A: Hydrocarbons, and B: Fundamental Heterocyclic Systems), 1965 (C: Characteristic Groups) (3 ed.). London: Butterworths. ISBN   0-408-70144-7.
2. "7.4: Naming Alkenes". Chemistry LibreTexts. 2015-05-03. Retrieved 2025-07-17.
3. "-ene - (Organic Chemistry) - Vocab, Definition, Explanations | Fiveable". library.fiveable.me.
4. "Ene Reactions". Chemistry LibreTexts. November 11, 2013.
5. Hofmann, A. W. (1866). "On the Action of Trichloride of Phosphorus on the Salts of the Aromatic Monamines". Proceedings of the Royal Society of London. 15: 54–62. ISSN   0370-1662.
6. "Alkane Nomenclature". chem125-oyc.webspace.yale.edu. Retrieved 2025-07-17.
7. Boehm, H. P.; Setton, R.; Stumpp, E. (1986-01-01). "Nomenclature and terminology of graphite intercalation compounds" . Carbon. 24 (2): 241–245. doi:10.1016/0008-6223(86)90126-0. ISSN   0008-6223.