Parameters describing solubilities of solid substances in ionic solvents

1 PARAMETERS DESCRIBING SOLUBILITIES OF SOLID SUBSTANCES IN IONIC SOLVENTS 

Dissolution of solid oxides in ionic melts is accompanied by the simultaneous interaction of the dissolving material with the melt ions. Metal cations are surrounded by the melt anions and oxide ions are fixed by constituent cations of the ionic medium. This results in the formation of different ionic complexes. Besides, a certain part of the powder added is dissolved in the melt without dissociation. The sum of the changes taking place in these processes is called solvation . So, any process of oxide dissolution in an ionic medium may be described by a system of equations. For the case of the formation of two-charged metal cation these are 

Since the process of complexation between the melt anion and different cations of close radii proceeds to practically equal degrees, one may assume that for a set of oxides dissolved in the same ionic solvent the solubility value should be dependent on the degree of acidic cation-anion interaction which is the Lux-Flood acid-base equilibrium. In this case, the constant of the 

Equilibria in solid oxide-ionic melt systems 

Taking into account the incomplete dissociation of metal oxides in ionic melts, the complete oxide solubility ( sMe0) can be represented by the sum of the activities (concentrations) of metal cations and non-dissociated oxide  

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