A new class of molten salt mixtures the hydrated dipositive ion as an independent cation species

On the basis of solubility and electrical conductance measurements, a new class of molten salt mixtures involving hydrated multivalent cations as independent cation species is proposed. It is shown that these ionsconfer essentially the same properties on the solutions as expected theoretically from hard sphere cations of the same charge: radius ratio. The solutions are of considerable potential interest since they have especially low liquidus temperatures for molten salt systems and, as a result, are frequently glass forming. The investigation of ionic liquid behavior at low free volumes (high densities)should, therefore, be possible in a variety of systems. By way of an example, KNO₃ is found to dissolve to the extent of some 70 tool % at 100^¼ in the “hydrate melt” Ca(NO₃)₂.4H₂O. The application of free volume transport theory equations to the analysis of electrical conductance data for this system produces striking correlations with electrical conductance behavior in the anhydrous system Ca(NO₃)₂+KNO₃.