Title: in-out isomerism
Long Title: IUPAC Gold Book - in-out isomerism
DOI: 10.1351/goldbook.I03055
Status: current

Definition
Isomerism found in bicyclic systems having long enough bridges to allow the bridgehead exocyclic bond or lone pair of electrons to point either inside the structure or outside.  

Related Terms
- Isomerism: https://goldbook.iupac.org/terms/view/I03294
- bridgehead: https://goldbook.iupac.org/terms/view/B00736

Source
- PAC, 1996, 68, 2193. 'Basic terminology of stereochemistry (IUPAC Recommendations 1996)' on page 2210 (https://doi.org/10.1351/pac199668122193)

Other Outputs
- html: https://goldbook.iupac.org/terms/view/I03055/html
- json: https://goldbook.iupac.org/terms/view/I03055/json
- xml: https://goldbook.iupac.org/terms/view/I03055/xml

Citation: Citation: 'in-out isomerism' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. 10.1351/goldbook.I03055
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Accessed: 2026-06-10T09:06:31+00:00