己烯

Hexylene \Hex"yl*ene\, n. [Hex- + -yl + ethlene.] (Chem.)
A colorless, liquid hydrocarbon, {C6H12}, of the ethylene
series, produced artificially, and found as a natural product
of distillation of certain coals; also, any one several
isomers of hexylene proper. Called also {hexene}.