Term: relative configuration
https://doi.org/10.1351/goldbook.R05260

Definition:
The configuration of any stereogenic (asymmetric) centre with respect to any other stereogenic centre contained within the same molecular entity. Unlike absolute configuration, relative configuration is reflection-invariant. Relative configuration, distinguishing diastereoisomers, may be denoted by the configurational descriptors R *, R * (or l) and R *, S * (or u) meaning, respectively, that the two centres have identical or opposite configurations. For molecules with more than two asymmetric centres the prefix rel- may be used in front of the name of one enantiomer where R and S have been used. If any centres have known absolute configuration then only R * and S * can be used for the relative configuration.

Related Terms:
1) α (alpha), β (beta) (defs. 1 and 3) (http://doi.org/10.1351/goldbook.A00003).
2) configuration (http://doi.org/10.1351/goldbook.C01249).
3) stereogenic units (http://doi.org/10.1351/goldbook.S05980-2).
4) (asymmetric) centre (http://doi.org/10.1351/goldbook.A00480).
5) absolute configuration (http://doi.org/10.1351/goldbook.A00020).
6) diastereoisomers (http://doi.org/10.1351/goldbook.D01679).
7) stereogenic (http://doi.org/10.1351/goldbook.S05980-1).
8) asymmetric (http://doi.org/10.1351/goldbook.A00478).
9) rel (http://doi.org/10.1351/goldbook.R05254).
10) enantiomer (http://doi.org/10.1351/goldbook.E02069).

Source: 

Citation: 'relative configuration' 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.R05260

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