The Chapman‐Jouguet detonation velocity and thermodynamic state variables are calculated for a representative set of CHON explosives, using the Lennard‐Jones and Devonshire cell theory equation of state together with a modified conformal solution treatment of the mixture problem, and allowing for chemical equilibrium among nine product species. Although fair agreement with experiment can be obtained by adjusting a single parameter of the pair potentials, the results are little better than those obtainable with much simpler theories.