The alkynes are a functional group characterized by the presence of a carbon-carbon triple bond. Originally the alkynes were called the acetylenes. This is still the common name given to the simplest member of the group, although the IUPAC name is ethyne (Figure 1) . The alkynes are all distinguished by the ending -yne.

Non-cyclic alkyne hydrocarbons, such as butyne (CH₃C=CCH₃), are characterized by an empirical formula of C_nH(_2n-2). The bonding relationship of the triple alkynes is most commonly described as bonding between two sp- p² hybridized carbon atoms. The alkyne carbon atoms bond together through one sigma bond, comprised of one of the two sp orbitals, and two pi bonds. The sigma bond occupies the internuclear space, and the two pi bonds are at 90° angles to each other surrounding the carbon-carbon internuclear space. This results in a linear relationship...