Term: homotopic
https://doi.org/10.1351/goldbook.H02857

Definition:
Atoms or groups of a molecule which are related by an n-fold rotation axis (n = 2, 3, etc.) are called homotopic. For example, chiral tartaric acid (C2 axis), chloroform (C3 axis) and cyclohexaamylose (α-cyclodextrin, C6 axis) have respectively two homotopic carboxyl groups, three homotopic chlorine atoms and six homotopic d-glucose residues.

Related Terms:
1) chiral (http://doi.org/10.1351/goldbook.C01057).
2) prochirality (http://doi.org/10.1351/goldbook.P04859).

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

Citation: 'homotopic' 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.H02857

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