The thermodynamic equation for the dissolution of solids in liquids.

A solvation model of a superficial layer on the liquid - solid interface is given. This model is applied for the description of the dissolution of sol id compounds in liquids. The superficial layer is supposed as a solid solut ion of a solvent in a solute of non-stoichiometric composition. It is descr ibed within the scope of the Debye model of a solid state. A peculiarity of the model is that the Debye temperature of the solid solution is a functio n of the partial densities of the solvent and the solute. The solvation eff ect is taken into account by using one constant - the Gruneisen solvation c onstant. For the temperature dependence and for the heat of dissolution ana lytical expressions are obtained. The expressions are functions of the Deby e characteristic temperature and the Gruneisen solvation constant of a supe rficial layer. Thorough comparison with the experiments on the dissolution and the heat of dissolution of the metals in liquid mercury is performed yi elding excellent agreement.