Quantum mechanics theory of chemical bonding that treats electrons as being assigned to individual bonds between particular atoms.
Notes: - The VB theory views a chemical bond as a result of weak coupling (overlapping) of atomic or hybridized atomic orbitals or of both and describes delocalization of electrons (inherent in molecular orbital theory) as a result of resonance mixing of two or more possible energetically equivalent or nearly equivalent structures.
- VB theory and molecular orbital theory are closely related methods that become equivalent when extended enough. Increasing mixing of VB orbitals gives in the limit extended molecular orbitals.
Source:
PAC, 2022, 94, 15. 'Glossary of terms relating to electronic, photonic and magnetic properties of polymers (IUPAC Recommendations 2021)' on page 50 (https://doi.org/10.1515/pac-2020-0501)