STRUCTURAL MODIFICATION IN MOLTEN-METAL CHLORIDE AND ALKALI CHLORIDE MIXTURES

Structure factors have been measured by time-of-flight neutron diffraction for NiCl2-KCl, NiCl2-LiCl and ZnCl2-LiCl binary molten salt mixtures. The results are consistent with those from earlier thermodynamic and spectrophotometric studies, in which the degree of structural modification was found to depend on the type of alkali cation. The NiCl2-LiCl and ZnCl2-LiCl systems appear to be almost ideal admixtures of the pure salts. However, adding KCl to NiCl2 results in enhancement of the local structure and intermediate range order. The first sharp diffraction peak at Q congruent-to 1 angstrom-1 in pure NiCl2, which is more prominent than previously reported, appears to be enhanced by the addition of KCl up to a high concentration of alkali halide. No change is apparent in NiCl2-LiCl or ZnCl2-LiCl.