Aliphatic hydrocarbons with one triple bond between carbons are called alkynes. They follow the naming convention of the alkanes except that the suffix -yne is used instead of -ane. For alkynes above propyne the position of the double bond must be specified in the name.

The simplest of the alkyne series, it is commonly called acetyline. It is often used as a fuel for welding torches sinces it produces a large amount of heat upon combustion. Oxyacetylene welding uses compressed acetylene and compressed oxygen for mixing in the torch flame.