Six π- Molecular Orbitals (MO's) of Benzene

(The appearance of molecular orbitals may take a few moments)

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Commands





The diagram below is a Frost-Hückel circle mnemonic. A polygon representing the ring system, in this case a regular hexagon for benzene, is inscribed in a circle with a vertex at the bottom. The energy levels of the six-π-MO's are placed at each vertex. The energy of an isolated p-orbital is taken as passing through the center of the circle. From the geometry of a regular hexagon, there should be equal separation of the three energy levels. Compare with the energies on the right. There are three bonding MO's and three anti-bonding MO's. MO's Ψ2 and Ψ3 are degenerate (same energy) bonding orbitals while Ψ4* and Ψ5* are anti-bonding degenerate orbitals. Bonding MO's are green/blue; anti-bonding MO's are red/blue.

 

 

Ψ6- Antibonding

Surfaces

6 nodes

Ψ4- Antibonding

Surfaces

4 nodes

Ψ5- Antibonding

Surfaces

4 nodes

Ψ2-Bonding

Surfaces

2 nodes

Ψ3-Bonding

Surfaces

2 nodes

Ψ1-Bonding

Surfaces

0 nodes