https://doi.org/10.1351/goldbook.RT07095
Electron @D01583@ realized in both acyclic and cyclic π-conjugated, 1, and σ-bonded, 2, ribbon-like systems.
RT07095.png
For cyclic systems, a variety of linkage fashions between several ribbons (pericyclic, spirocyclic, longicyclic and laticyclic) is possible.