Term: enantiotopic
https://doi.org/10.1351/goldbook.E02083

Definition:
Constitutionally identical atoms or groups in molecules which are related by symmetry elements of the second kind only (mirror plane, inversion centre or rotation–reflection axis). For example the two groups c in a grouping Cabcc are enantiotopic. Replacement of one of a pair of enantiotopic groups forms one of a pair of enantiomers. Analogously, if complexation or addition to one of the two faces defined by a double bond or other molecular plane gives rise to a chiral species, the two faces are called enantiotopic.

Related Terms:
1) prochiral (http://doi.org/10.1351/goldbook.P04859).
2) diastereotopic (http://doi.org/10.1351/goldbook.D01685).
3) inversion (http://doi.org/10.1351/goldbook.I03146).
4) chiral (http://doi.org/10.1351/goldbook.C01057).

Source: PAC, 1996, 68, 2193. 'Basic terminology of stereochemistry (IUPAC Recommendations 1996)' on page 2207 (https://doi.org/10.1351/pac199668122193)

Citation: 'enantiotopic' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. https://doi.org/10.1351/goldbook.E02083

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