What does alkyne mean?
An alkyne is a type of hydrocarbon — a compound made only of carbon and hydrogen — that contains at least one carbon–carbon triple bond. This triple bond makes alkynes unsaturated and highly reactive compared with alkanes, which have only single bonds, and alkenes, which have double bonds. Alkynes follow the general formula CₙH₂ₙ₋₂, and the best-known member is ethyne, widely known by its older name acetylene, once prized for welding torches and lamps. Chemists name alkynes using the suffix '-yne,' as in ethyne or propyne, distinguishing them clearly from their single- and double-bonded relatives. In modern practice, alkynes are important building blocks in organic synthesis: reactions such as the Sonogashira coupling use them to construct complex molecules found in pharmaceuticals, materials, and natural products. Though chiefly a term of laboratory and classroom science rather than everyday conversation, the word is central to understanding how bonding shapes chemical behavior.
nounAn unsaturated hydrocarbon containing at least one carbon–carbon triple bond, with the general formula CₙH₂ₙ₋₂; the simplest example is acetylene (ethyne).
- A chemistry sense: any acyclic or cyclic hydrocarbon containing one or more carbon–carbon triple bonds, forming a homologous series with the general formula CₙH₂ₙ₋₂.
"The terminal alkyne reacted readily in the Sonogashira coupling to form a new carbon–carbon bond."
"Ethylene and acetylene differ fundamentally: acetylene is an alkyne, with two carbon atoms joined by a triple bond."
"In organic chemistry coursework, students learn to distinguish an alkyne from an alkene by testing how each reacts with bromine."
Standard plural, used both for multiple specific compounds and for the class as a whole in chemical writing.
"Several naturally occurring alkynes have been isolated from plants and fungi."
The '-yne' ending was invented purely so chemists could keep their naming system tidy — swapping one letter turns an alkene into its triple-bonded cousin.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of alkyne
The word 'alkyne' is a modern scientific construction dating from the late nineteenth century. It adapts 'alkene' by replacing the '-ene' ending with '-yne,' following the Hantzsch–Widman convention that assigns distinct suffixes to different degrees of unsaturation. The broader root traces back through 'alkyl' and 'alcohol' — terms coined in European chemistry from the Arabic article 'al-' combined with roots relating to substances distilled or calcined. The '-yne' suffix itself derives from the '-ine' ending common in chemical nomenclature of the period.
How alkyne is actually used
A technical term used almost exclusively in organic chemistry and related sciences; it is neutral in register but unfamiliar to most lay readers. In IUPAC nomenclature, alkynes are named with the suffix '-yne' (e.g., ethyne, propyne). The simplest alkyne, ethyne, is more commonly called by its trivial name 'acetylene.'
Easily confused with alkyne
An alkane is a fully saturated hydrocarbon with only single bonds and the formula CₙH₂ₙ₊₂, whereas an alkyne contains at least one carbon–carbon triple bond.
An alkene contains at least one carbon–carbon double bond (C=C) with general formula CₙH₂ₙ, while an alkyne contains a triple bond (C≡C).
An alkyl is a substituent group derived from an alkane by removing one hydrogen atom, not a class of hydrocarbons like an alkyne.