Woodward–Hoffmann rules
In the generalized Woodward–Hoffmann rules, everything is characterized in terms of antarafacial and suprafacial bond topologies. The terms "conrotatory" and "disrotatory" are sufficient for describing the relative sense of bond rotation in electrocyclic ring closing or opening reactions, as illustrated on the right. However, they are unsuitable for describing the topologies of bond forming and breaking taking place in a general pericyclic reaction. As described in detail below, in the general formulation of the Woodward–Hoffmann rules, the bond rotation terms "conrotatory" and "disrotatory" are subsumed by the bond topology (or faciality) terms "antarafacial" and "suprafacial", respectively. These descriptors can be used to characterize the topology of the bond forming and breaking that takes place in any pericyclic process.