D

Delocalization

π electrons spread over >2 atoms; resonance
Quick Reference
Formula / Notationπ electrons spread over >2 atoms; resonance
Also Known AsElectron delocalisation; resonance; π-electron delocalisation; delocalised electrons; mesomerism; conjugation

What is Delocalization?

Delocalization in chemistry refers to the distribution of electrons (particularly π electrons or lone pairs) over more than two atoms in a molecule, rather than being localised between one pair of atoms. It occurs in conjugated systems, aromatic compounds, and molecules described by resonance structures. Delocalization generally stabilises molecules (resonance stabilisation energy).

Formula & Notation

π electrons spread over >2 atoms; resonance

Other Names / Synonyms: Electron delocalisation; resonance; π-electron delocalisation; delocalised electrons; mesomerism; conjugation

Properties & Characteristics

Electrons shared across multiple atomic centres; characteristic of aromatic compounds (benzene ring), conjugated systems (1,3-butadiene), and resonance structures (CO₃²⁻, NO₃⁻); stabilises molecules (aromatic stabilisation ~150 kJ/mol for benzene); reduces bond length variation; described by molecular orbital theory

Uses & Applications

Explaining stability of aromatic compounds; predicting reactivity (EAS reactions); conducting polymers (polyacetylene, polyaniline); organic semiconductors; photochemistry and UV-Vis spectroscopy; understanding resonance stabilisation in biochemical molecules (amino acids, porphyrins)

Safety Information

No hazard — a theoretical chemistry concept.

Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.

Key Facts

Term Delocalization
Formula π electrons spread over >2 atoms; resonance
Synonyms Electron delocalisation; resonance; π-electron delocalisation; delocalised electrons; mesomerism; conjugation

Frequently Asked Questions

Delocalization in chemistry refers to the distribution of electrons (particularly π electrons or lone pairs) over more than two atoms in a molecule, rather than being localised between one pair of atoms. It occurs in conjugated systems, aromatic compounds, and molecules described by resonance structures. Delocalization generally stabilises molecules (resonance stabilisation energy).

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