Term: antibonding molecular orbital
https://doi.org/10.1351/goldbook.AT06988

Definition:
The molecular orbital whose occupation by electrons decreases the total bonding (as usual, increases the total energy) of a molecule. The energy level of an antibonding MO lies higher than the average of the valence atomic orbitals of the atoms constituting the molecule.

Related Terms:
1) molecular orbital (http://doi.org/10.1351/goldbook.M03996).
2) valence (http://doi.org/10.1351/goldbook.V06588).

Source: PAC, 1999, 71, 1919. 'Glossary of terms used in theoretical organic chemistry' on page 1923 (https://doi.org/10.1351/pac199971101919)

Citation: 'antibonding molecular orbital' 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.AT06988

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