Title: Re, Si
Long Title: IUPAC Gold Book - <i>Re</i>, <i>Si</i>
DOI: 10.1351/goldbook.R05308
Status: current

Definition
A stereoheterotopic face of a trigonal atom is designated Re if the ligands of the trigonal atom appear in a clockwise sense in order of CIP priority when viewed from that side of the face. The opposite arrangement is termed Si.

Related Terms
- CIP priority: https://goldbook.iupac.org/terms/view/C01082
- enantiotopic: https://goldbook.iupac.org/terms/view/E02083
- ligands: https://goldbook.iupac.org/terms/view/L03518
- prochirality: https://goldbook.iupac.org/terms/view/P04859
- stereoheterotopic: https://goldbook.iupac.org/terms/view/S05981

Source
- PAC, 1996, 68, 2193. 'Basic terminology of stereochemistry (IUPAC Recommendations 1996)' on page 2216 (https://doi.org/10.1351/pac199668122193)

Other Outputs
- html: https://goldbook.iupac.org/terms/view/R05308/html
- json: https://goldbook.iupac.org/terms/view/R05308/json
- xml: https://goldbook.iupac.org/terms/view/R05308/xml

Citation: Citation: '<i>Re</i>, <i>Si</i>' 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.R05308
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Accessed: 2026-05-10T02:45:23+00:00