# How can I assess strain energy of cyclopropane and aromatic stabilization of benzene with homodesmotic reactions?

May 19, 2015

You can find out how to assess the strain energy of cyclopropane here.

To assess the aromatic stabilization of benzene, you determine the energy change for the reaction

${\text{C"_6"H"_6 + "3CH"_2"=CH"_2 → "3CH"_2"=CH–CH=CH}}_{2}$

All bonds are $s {p}^{2}$ C-H σ bonds, C-C σ bonds, and C-C π bonds.

Each side of the equation has

• 18 $s {p}^{2}$ σ C-H bonds
• 3 $s {p}^{2}$ σ C-C bonds
• 6 $s {p}^{2}$ C-C π bonds

Since all bond types are matched, the value of ΔH represents the aromatic stabilization of benzene.