Steric effects vs electron delocalization: a new look into stability of diastereomers, conformers and constitutional Isomers

A quantum chemical investigation of the stability of compounds with identical formulas was carried out on 23 classes of compounds made of C, N, P, O, S atoms as core structures and halogens H, F, Cl, Br, I as substituents. All possible structures were generated and investigated by quantum mechanical methods. The prevalence of formula in which its Z configuration, gauche conformation and meta isomer are the most stable forms is calculated and discussed. Quantitative and qualitative models to explain the stability of the 23 classes of halogenated compounds were also proposed.