New Method for Predicting the Enthalpy of Salt Formation

Abstract

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.

Thermochemistry and crystal structure predictions of energetic derivatives of formamidine salts

“…We recently proposed a new method for estimating the enthalpies of salt formation – the Method of Ions and Cocrystals Contribution Mixing (MICCM, Khakimov's method). 19 This method surpasses the known methods in the accuracy of estimation of the enthalpies of formation of salts, and therefore we used it to evaluate this characteristic for the series of compounds under consideration.…”

Is Everything Correct? The Formation Enthalpies Estimation and Data Revision of Nitrates and Perchlorates Salts

“…Based on the methodology and results for nitrate salts obtained by us in [17], the enthalpies of formation for a number of organic and inorganic salts of perchlorates were estimated (Table 3). As can be seen from this table, the enthalpies of formation agree fairly well with the experimental values.…”

“…Calculated enthalpies of formation for organic and inorganic salts of nitrates and perchlorates. -average value for [DAGH] + (diaminoguanidinium) for nitrate and dinitramide anion[17].It is clearly seen from Table3that the MAIC method gives excellent agreement with experiment within 1-2 kcal mol − 1 . The MICCM values are somewhat worse and the differences from the experiment are up to 3-4 kcal mol − 1 .…”

“…The recently developed new method for estimating the enthalpies of salt formation -the Method of Ions and Cocrystals Contribution Mixing (MICCM, Khakimov's method) [17] is based on fundamentally different provisions than the VBT and MAIC methods, it is an ab initio method and therefore allows you to perform an alternative assessment of the quality of calculations speci ed methods.…”

Novel family of nitrogen-rich energetic (1,2,4-triazolyl) furoxan salts with balanced performance

“…The new approach for salts proposes a technique based on modeling the crystal packing for a salt and a similar neutral compound (quasi-salt, cocrystal). The enthalpy of formation in this case is calculated as the average value between these two structures ( Khakimov and Pivina, 2022 ).…”