This proposal is a continuation of a study of molten salts which have a large number of applications, including applications in fuel cells and, in the case of nitrates, as transfer fluids in solar energy capture. Combined diffraction and simulation studies have been used to make specific predictions about the diffusion of sodium in these molten salt liquids and we have used the QENS technique in a previous experiment to establish the diffusion of sodium, taking full advantage of the completely coherent contribution from the carbonate anions and the fully coherent contribution from sodium. In this proposed experiment we will study both sodium and potassium nitrate liquids combining QENS data with our robust diffraction and simulation approach to derive diffusion constants and to evaluate the fragility of these technically important liquids.