Here, we also looked at the structure of multiple bi-valent, mono-valent, tri-valent, and quad-valent salt mixtures. In the total pair distribution function shown in Figure , for light elements (i.e., Li, K, Ca, Na), the 1st peak has contributions from the cation-anion bond and the 2nd peak is mainly due to the contribution from the Cl-Cl bond. However, for mixtures with heavy elements, even though the Cl concentration is higher, according to the weight factor, the main contributions to the 2nd and 3rd peaks are from the heavy cationheavy cation (e.g., Th-Th and Nd-Nd) correlations. The detailed structure information, such as bond length and coordination number for individual bonds, is derived from the partial PDF of these salt mixtures and listed in Table . The average Th-Cl coordination number (CN) in the KCl-ThCl 4 mixture was found to be 6.21, which is consistent with prior stud-ies indicating that at high ThCl 4 concentrations, the primary species in ThCl 4 -ACl (A = alkali metal) are 6-coordinated octahedra, including linked ThCl 6and chained [Th n Cl 4n+2 ] 2- and [Th n Cl 4n+2 ] 2+ . Similarly, the average Nd-Cl CN in the KCl-NdCl 3 mixture was 6.33, also in agreement with previous research suggesting that a distorted octahedral loose network structure predominates in NdCl 3 -ACl mixtures with high NdCl 3 concentrations (> 25 mol%). The structure factor of different salt mixtures is shown in Figure . Salt mixtures with ThCl 4 and NdCl 3 show very intense pre-peaks at around ∼0.8Å -1 to ∼1.05Å -1 which indicates a strong intermediate range ordering.