Delocalization of Electrons

Section 14.3

Introduction

Delocalization allows the pi electrons to spread over more than two nuclei

This spreading out of the electrons gives the species a lower potential energy making it more stable

Best example is with benzene The molecule is a planar hexagonal shape Each carbon atom is sp2 hybridized

More about Benzene

One of the sp2 orbitals forms a sigma bond with H Two other orbitals forms sigma bonds with the C on

each side The remaining electron is in a p-orbital

perpendicular to the plane of the sigma bonds These p-orbitals on each C atom interact to produce

a delocalized pi bond The ring has high electron density above and below

the ring

Benzene Ring

Ethene (C2H4) Benzene (C6H6)

More

Resonance hybrids show delocalization of electrons which leads to: Greater stability and an intermediate bond length

and strength Less reactivity Ability to conduct electricity (because electrons are

more free to move, i.e. delocalized)