The total structure factor data of the NaCl-CaCl 2 mixture at various compositions are shown in Figure . A pre-peak at approximately 1.44 Å -1 appears in the CaCl 2 S(Q) plot which is not present in the NaCl S(Q) plot (zoomed in Figure ). A peak near 1.04 Å -1 appears in the structure factor when NaCl is introduced into CaCl 2 . These two peaks are most likely the results of intermediate range order in CaCl 2 and CaCl 2 -NaCl mixtures which are also observed in other AX 2 systems . The peak at 1.04 Å -1 is probably attributable to the periodicity of Cl -in adjacent ionic networks (chains) as mentioned by Wu et al. It is also worth pointing out that the simulations using the RIM model cannot accurately predict the structure of mixtures with multiply charged cations . This means the ML-MD can accurately capture both the details in the shortrange structure and the intermediate-range structure of complex molten salt mixtures.