Special features of structure formation of sodium chloride concentrated aqueous solution on its passing to supercritical state

Structural properties of aqueous 4.37 M solution of NaCl under sub-and supercritical conditions (p 25 MPa, T 450–750 K) were studied by the method of integral equations in the atom-atom approximation. The passing of the system to the supercritical state is accompanied by a substantial rearrangements in local structural fragments with hydrogen bonds and in the nearest surrounding of the ions. In this case a transition is observed from the solution structure with hydrated ions and ionic pairs (subcritical region) to the structure with free molecules and low-molecular formations, probably, in the form of clusters (supercritical region).