Term: eclipsed (eclipsing)
https://doi.org/10.1351/goldbook.E01884

Definition:
Two atoms or groups attached to adjacent atoms are said to be eclipsed if the torsion angle between the three bonds is zero (or approximately so).

Related Terms:
1) torsion angle (http://doi.org/10.1351/goldbook.T06406).
2) bisecting conformation (http://doi.org/10.1351/goldbook.B00673).
3) eclipsing strain (http://doi.org/10.1351/goldbook.E01886).

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

Citation: 'eclipsed (eclipsing)' 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.E01884

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