Electron delocalization realized in both acyclic and cyclic π-conjugated, 1
, and σ-bonded, 2
, ribbon-like systems.
For cyclic systems, a variety of linkage fashions between several ribbons (pericyclic, spirocyclic, longicyclic and laticyclic) is possible.
PAC, 1999, 71, 1919. 'Glossary of terms used in theoretical organic chemistry' on page 1961 (https://doi.org/10.1351/pac199971101919)