1. Delocalization of Electrons Section 14.3

2. 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 sp 2 hybridized

3. More about Benzene One of the sp 2 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

4. Benzene Ring

5. Ethene (C 2 H 4 )Benzene (C 6 H 6 )

6. 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)