A bicyclic molecule's a molecule that features two fused rings. Bicyclic molecules occur in widely in organic and inorganic compounds. Fusion of the rings can occur in three ways: Across a bond between two atoms - for example, decalin, a.k.a. bicyclo[4.4.0]decane, has a C-C bond shared between two cyclohexane rings; Across a sequence of atoms (bridgehead) - for example, norbornane, a.k.a. bicyclo[2.2.1]heptane, can be viewed as a pair of cyclopentane rings that share three of the five carbon a… (More on Bicyclic)