isoprene

A colorless volatile liquid, C₅H₈, used chiefly to make synthetic rubber.

A hydrocarbon (C₅-H₈), one of the hemiterpenes, produced in the destructive distillation of india-rubber or gutta-percha, and also obtainable from oil of turpentine.

An oily, volatile unsaturated hydrocarbon (C5H8), obtained by the distillation of caoutchouc or gutta-percha, and used to make synthetic rubber by polymerization. In organic chemistry, it is viewed conceptually as the building block of the terpene series of hydrocarbons.

An unsaturated hydrocarbon, C5H8, that is readily polymerized; natural rubber (caoutchouc) is cis-1,4-polyisoprene, and trans-1,4-polyisoprene is present in gutta-percha and balata; it is the structural basis for the terpenes.