Modeling enthalpy and hydration properties of inorganic compounds

The method of linear combinations of connectivity indices has been applied to fit the following physicochemical properties of inorganic molecules: the lattice enthalpies of 32 inorganic compounds, the limiting enthalpies of solution of 12 metal halides, the unfrozen water content, the relative humidity and eutectic temperature of metal chlorides and the unfrozen water content of a mixed set of amino acids and metal chlorides. The achieved fit is very satisfactory and it can be normally attained with the help of a single-index linear combination. The obtained fit draws also a validity test for the delta delta(upsilon) valence number of the inorganic compounds and for a newly defined D-Z index based on the number of valence electrons and on the principal quantum number. The fit of the unfrozen water content of the mixed set of amino acids and metal chlorides, achieved by means of linear combinations of reciprocal connectivity indices can be seen as a first hint far the construction of a connectivity model encompassing both organic and inorganic compounds.