delocalization

chemistry

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June 25, 2026

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In chemistry, delocalization refers to the distribution of bonding electrons over more than two atoms in a molecule. This concept is crucial in understanding chemical bonding beyond simple localized electron pairs.1

When electrons are delocalized, their influence is spread across multiple atoms, contributing to the overall stability of the molecule. This is particularly evident in theories like molecular orbital (MO) theory, where electrons occupy orbitals that extend over the entire molecule, rather than being confined between two specific atoms.1

A prime example of delocalization is seen in the theory of resonance, where a molecule's true state is represented as a hybrid of several distinct valence-bond structures. This resonance stabilizes the molecule by lowering its energy compared to any single hypothetical structure. The classic illustration is the benzene molecule, where electron delocalization makes all carbon-carbon bonds equivalent. Delocalization also helps explain phenomena like hypervalence and electron-deficient compounds without needing to invoke complex orbital expansions.21

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chemical bonding
Molecular orbitals of polyatomic species
That is, they are delocalized orbitals, and electrons that occupy them are delocalized over several atoms (here, as many as six atoms, as in the 1a orbital).
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That is, they are delocalized orbitals, and electrons that occupy them are delocalized over several atoms (here, as many as six atoms, as in the 1a orbital).
Read More