12 Examples of Alkynes

A few common examples of alkynes include ethyne (acetylene), propyne, and butyne. Ethyne has the simplest structure (C2H2) with a triple bond between two carbons while propyne (C3H4) and butyne (C4H6) have triple bonds with longer carbon chains. Other basic alkynes are 2-pentyne, 3-hexyne, and 1-heptyne, which have 5, 6, and 7 carbon chains respectively featuring highly reactive triple bonds.

The electron density around the carbon-carbon triple bonds causes alkynes to display increased reactivity compared to other hydrocarbons.

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Examples of Alkynes

Here are 10 examples of alkynes:

1: Terminal Alkynes

Terminal alkynes have a carbon-carbon triple bond at the end of the carbon chain. This bond consists of 1 sigma and 2 perpendicular pi bonds between two sp-hybridized carbon atoms.


  • Ethyne (Acetylene): C2H2
  • Propyne: CH≡C-CH3
  • But-1-yne: CH≡C-CH2-CH3
  • Pent-1-yne: CH≡C-CH2-CH2-CH3
  • Hex-1-yne: CH≡C-(CH2)3-CH3

2: Symmetrical Internal Alkynes

Symmetrical internal alkynes have a carbon-carbon triple bond between two internal carbons equidistant from the ends of the chain.


  • Buta-2,3-diyne: CH≡C-C≡CH
  • Penta-2,4-diyne: CH≡C-CH2-C≡CH
  • Hepta-2,4-diyne: CH≡C-(CH2)2-C≡CH
  • Nona-2,5-diyne: CH≡C-(CH2)3-C≡CH
  • Undeca-3,6-diyne: CH≡C-(CH2)4-C≡CH

3: Asymmetrical Internal Alkynes

Asymmetrical alkynes contain a triple bond located internally at unequal distances from the ends of the carbon chain.


  • 3-Hexyne: CH≡C-CH2-CH2-CH3
  • 5-Decyne: CH3-(CH2)3-C≡C-(CH2)4-CH3
  • 2-Nonyne: CH3(CH2)6-C≡CH
  • 4-Tetradecene: CH≡C-(CH2)11-CH3
  • 7-Hexadecene: CH≡C-(CH2)13-CH3

4: Cycloalkynes

Cycloalkynes contain a carbon-carbon triple bond within a saturated or unsaturated carbon ring structure.


  • Cyclopropyne: c-C3H4
  • Cyclohexyne: c-C6H8
  • Cyclododecyne: c-C12H20
  • 1,3,5-Cyclodecatriyne

5: Fluoroalkynes

Fluoroalkynes have at least one carbon substituted with a fluorine atom. The electronegativity affects reactivity.


  • 3,3,3-Trifluoropropyne
  • 4,4,4-Trifluorobutyne
  • Perfluorobutyne
  • 1-(Trifluoromethyl)-1-propyne
  • 3,3,4,4,4-Pentafluorobutyne

6: Aryl Alkynes

Aryl alkynes contain a carbon-carbon triple bond with at least one aryl group (benzene ring structure) attached.


  • Phenylacetylene: C6H5-C≡CH
  • 4-Ethynyltoluene: CH3-C6H4-C≡CH
  • 3-Ethynylpyridine: NC5H4-C≡CH
  • 1-Naphthylacetylene: C10H7-C≡CH
  • 4-tert-Butylphenylacetylene: (CH3)3CC6H4-C≡CH

7: Haloalkynes

Haloalkynes contain one or more halogen atoms (F, Cl, Br, I) substituted on a carbon of the carbon-carbon triple bond.


  • Chloroacetylene: Cl-C≡CH
  • Dichloroacetylene: Cl-C≡C-Cl
  • 1-Chloropropyne: Cl-C≡C-CH3
  • 4-Bromopentyne: Br-(CH2)2-C≡CH
  • 1-Iodo-3-hexyne: I-CH2-CH2-CH2-C≡CH

8: Alkynols

Alkynols feature a hydroxy group (-OH) on the carbon adjacent to the alkyne carbon-carbon triple bond.


  • Propargyl alcohol: HC≡CCH2OH
  • 1-Butyn-3-ol: CH3CH2C≡CCH2OH
  • 3-Hexyn-1-ol: CH3(CH2)2C≡CCH2OH
  • 1-Octyn-4-ol: CH3(CH2)5C≡CCH2OH
  • 2-Nonyn-6-ol: CH3(CH2)4C≡CCH2CH2CH2CH2OH

9: Carbonyl Alkynes

Carbonyl alkynes contain two alkyl or aryl groups attached to a carbon-carbon triple bond having a carbonyl group on one end.


  • Propiolaldehyde: HC≡CCHO
  • Hex-3-yn-2-one: CH3CH2CH2C≡C(C=O)CH3
  • Phenyl propiolic acid: C6H5-C≡C-COOH
  • Ethynyl p-tolyl ketone: CH3-C6H4-C≡C(C=O)-CH3
  • 5-Undecynal: CH≡C-(CH2)8-CHO

10: Enynes

Enynes contain a carbon-carbon triple bond conjugated with a C=C double bond. This alternation affects reactivity.


  • 3,7-Octadiyne: HC≡C-CH=CH-C≡CH
  • 1,3,7-Decatriene: CH≡CH-CH=CH-CH2-CH=CH2
  • 5,9-Hexadecadiene: CH≡C-(CH2)7-CH=CH-(CH2)7-CH3
  • 2-Buten-1-yne: CH≡C-CH=CHCH3
  • 5-Undecene-8-yne: CH2=CH-(CH2)3C≡C(CH2)5CH3

11: Cumulenes

Cumulenes contain two or more triple bonds in a carbon chain with no single bonds in between. This builds up angle strain.


  • Butatriene: H-C≡C-C≡C-H
  • Octatetrayne: HC≡C-C≡C-C≡C-C≡CH
  • Dodecapentayne: HC≡C-C≡C-(CH2)3-C≡C-(CH2)3-C≡CH
  • Diphenylbutadiyne: C6H5-C≡C-C≡C-C6H5
  • Hexylheptatetrayne: CH3(CH2)5-C≡C-C≡C-(CH2)2-C≡C-C≡CH

12: Trialkynes

Trialkynes have an sp hybridized central carbon bound to three separate alkynyl groups in a tetrahedral geometry.


  • Ethyl 3-(buta-1,3-diynyl)pent-2-ynoate
  • Propane-1,1,1-triyltris(benzene-4,1-diyl) triacetate
  • 4-(Prop-2-yn-1-yl)-6-(but-3-yn-1-yl)phenyl 4-(pent-4-yn-1-yl)benzoate
  • 1,1,1-tris(phenylethynyl)ethane
  • 5-(4-bromophenylethynyl)-10,15-bis(phenylethynyl)zinc porphyrin

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