Illustrated Glossary of Organic Chemistry

Conjugation: Special stability associated with three or more adjacent, parallel, overlapping p orbitals, resulting in increased electron delocalization and longer electron wavelengths. Not limited to pi-sigma-pi bond arrangements.

Some conjugated species. Conjugated atoms and lone pairs shown in red.


Cyclooctatetraene is not conjugated. The pi bonds are not parallel, so each p orbital is parallel to just one other p orbital.