EXAFS STUDIES OF MOLTEN ZNCL2, RBCL AND RB2ZNCL4

The local structures of molten ZnCl2, RbCl and Rb2ZnCl4 are measured w ith the EXAFS technique. Several models are used to analyse the data, and some structural parameters as well as the radial distribution func tions of the nearest-neighbour atoms around Zn or Rb atoms are obtaine d. The tetrahedra consisting of four Cl atoms around Zn are found to b e dominant and stable in molten ZnCl2. The skewed behaviour of the rad ial distribution function for Rb-Cl in molten RbCl is also found, whil e the local structures around Rb can be regarded as a persistence of t he solid state but with strong short-range disorder. In molten Rb2ZnC4 , a network linked by Zn Cl4 groups is not found and the nearest-neigh bour structures around Rb atoms are more disordered than in molten RbC l. This has also confirmed that the EXAFS method can provide reliable information about the nearest-neighbour atom-atom coordination for som e molten salts, which is helpful in specifying the pairwise interactio n potential.