Thermochemistry and crystal structure predictions of energetic derivatives of formamidine salts

The crystal structure of substituted formamidine salts has been modeled on the basis of a combination of quantum chemistry methods and atom-atom potentials. Based on the new author's method (MICCM) for calculating the enthalpies of formation of salts, which is based on the model of a cocrystal consisting of a mixture of cations and anions and a "quasi-salt" of the neutral components of the salt itself, the formation enthalpy is calculated as the average between the enthalpies of formation of these two structural components for salts various formamidines and the contributions of the corresponding cations to the calculation scheme are given. The results are in good agreement with the experimental data obtained by combustion calorimetry. Crystal packings were modeled for salts of substituted formamidines including formamidinium, guanidinium, azidoformamidinium and nitroformamidinium. The enthalpies of formation for substituted formamidines with various anions were calculated.