 They differ only in the position of the alkene moiety, with the double-bond being endocyclic (part of the five-membered ring) in α-cubebene, as shown, but exocyclic in β-cubebene.It is a pale green viscous liquid with a warm woody, slightly camphoraceous odor.After rectification with water, or on keeping, this deposits rhombic crystals of camphor of cubeb.