Term: bond-stretch isomers
https://doi.org/10.1351/goldbook.08148

Definition:
Two (or more) molecules with the same spin multiplicity but with different lengths for one or more bonds.

Note: This feature arises because the potential-energy surface, which describes how the energy of the molecule depends on geometry, shows two (or more) minima that are not merely symmetry-related.

Source: PAC, 2022, 94, 353. 'Glossary of terms used in physical organic chemistry (IUPAC Recommendations 2021)' on page 373 (https://doi.org/10.1515/pac-2018-1010)

Citation: 'bond-stretch isomers' 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.08148

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