3-Hexyne is the organic compound with the formula C<sub>2</sub>H<sub>5</sub>CCC<sub>2</sub>H<sub>5</sub>. This colorless liquid is one of three isomeric hexynes. 3-Hexyne forms with 5-decyne, 4-octyne, and 2-butyne a series of symmetric alkynes. It is a reagent in organometallic chemistry.