New Method for Predicting the Enthalpy of Salt Formation

A new efficient method for calculating the enthalpies
of salt formation
is proposed. The method is based on a fundamentally new cocrystal
model, consisting of a mixture of cations and anions and a “quasi-salt”
of neutral components, in fact, of the salt itself, and the enthalpy
of formation is calculated as the average value between the enthalpies
of formation of these two structural components. Unlike correlation
and additive schemes, this method is based on the construction of
a real physical model of a salt crystal, for which the molecular geometry
of the ions and neutral salt components is preliminarily optimized
by quantum chemistry methods. Further, based on the obtained data,
the initial models of crystal lattices in the statistically most probable
structural classes are constructed with their subsequent optimization
by the method of Atom–Atom potentials. For a number of compounds
of various chemical classes, the effectiveness of the method for estimating
the enthalpy of salts is shown, which surpasses the known methods
in terms of calculation accuracy.