Term: eclipsing strain
https://doi.org/10.1351/goldbook.E01886

Definition:
intramolecular strain present due to nonbonded interactions between two eclipsed atoms or groups. It is, for example, one of the interactions responsible for the existence of a rotational barrier and hence restricted rotation about the C–C bond in ethane. It has also been called Pitzer strain, torsional strain and bond opposition strain.

Related Terms:
1) intramolecular (http://doi.org/10.1351/goldbook.I03130).
2) strain (http://doi.org/10.1351/goldbook.S06037).
3) nonbonded interactions (http://doi.org/10.1351/goldbook.N04183).
4) eclipsed (http://doi.org/10.1351/goldbook.E01884).
5) rotational barrier (http://doi.org/10.1351/goldbook.R05408).
6) restricted rotation (http://doi.org/10.1351/goldbook.F02520).

Source: PAC, 1996, 68, 2193. 'Basic terminology of stereochemistry (IUPAC Recommendations 1996)' on page 2206 (https://doi.org/10.1351/pac199668122193)

Citation: 'eclipsing strain' 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.E01886

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