5 Decyne

5-Decyne, also known as dibutylethyne, is a type of alkyne with a triple bond at its fifth carbon (the '5-' indicates the location of the triple bond in the chain). Its formula is C₁₀H₁₈. Its density at 25 °C and otherwise stable conditions is 0.766 g/ml. The boiling point is 177 °C. The average molar mass is 138.25 g/mol.

5-Decyne forms with 4-octyne, 3-hexyne, and 2-butyne a group of symmetric alkynes.