Structural analysis of the molten salt 50 mol% AlCl3–50 mol% NaCl by X-ray diffraction

Abstract

The structure of the molten salt 50 mol% AlCl₃–50 mol% NaCl has been investigated using the radial distribution function based on X-ray scattered intensity data collected at 200 °C and has been analysed by the correlation method. Using an analysis of the first peak of the radial distribution function it has been confirmed that the main ion existing in this molten salt is AlCl^–₄. The nearest-neighbour distances between the Al–Cl, Na–Cl, Cl–Cl and Na–Al pairs are 2.13, 2.80, 3.48 and 4.20 Å, respectively. There are ca. eight NaAlCl₄ units around each NaAlCl₄ unit, with an average interunit distance of 6.98 Å. These results are in good agreement with those obtained from a computer simulation using the molecular-dynamics method.