https://doi.org/10.1351/goldbook.08166
Method using curly arrows for showing the formal movement of an electron pair (from a lone pair or a \(\upsigma\) or \(\ce{\uppi\ bond}\)) or of an unpaired electron, in order to generate additional resonance forms or to denote a chemical reaction.
Notes:
- The electron movement may be intramolecular or intermolecular.
- When a single electron is transferred, a single-headed curly arrow or "fish-hook" is used, but the electron movement in the opposite direction is redundant and sometimes omitted.
Examples: