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.
Source:
PAC, 2022, 94, 353. 'Glossary of terms used in physical organic chemistry (IUPAC Recommendations 2021)' on page 410 (https://doi.org/10.1515/pac-2018-1010)