Alkyne

Alkynes are hydrocarbons that have at least one triple bond between two carbon atoms. The alkynes are traditionally known as acetylenes, though the name acetylene is also used to refer specifically to the simplest member of the series, known officially as ethyne.

Structure

The carbon atoms in an alkyne bond are sp hybridized and carry 2 p orbitals and one sp hybrid orbital. The p orbitals overlap and create two pi bonds. In addition, two sp orbitals overlap to form one sp-sp sigma bond and now the total number of bonds is three. This makes that in the parent compound acetylene the H-C-C bond angles are 180°. Because a total of 6 electrons take part in bonding this triple bond is very strong with a bond strength of 837 kJ/mol. The sigma bond contributes 369 kJ/mol, the first pi bond contributes 268 kJ/mol and the second pi bond is weak with 202 kJ/mol bond strength. The CC bond distance with 121 picometers is also much less than that of the alkene bond which is 134 pm or the alkane bond with 153 pm.

Related Topics:
Sp hybridized - P orbital - Sp hybrid orbital - Pi bond - Sigma bond - Acetylene - Bond angle - Bond strength - Picometer - Alkene

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