STRUCTURE OF MOLTEN IRON CHLORIDE - NEUTRON-SCATTERING AND MODELING

Neutron-diffraction measurements of molten FeCl3, combined with model calculations and computer simulations, show that on melting the local structure of Fe changes from an octahedral to a tetrahedral environmen t. A similar change is observed in AlCl3, in contrast to YCl3, for exa mple, where the octahedral coordination of Y is preserved on melting. The local structure of the liquid can be described in terms of Fe2Cl6 molecular units, similar to those observed in the vapor phase but with strong intermolecular interactions. Detailed information about the or ientational correlations between molecules is derived from the simulat ions and compared with recent results on another molecular liquid, pro pylene glycol. [S0163-1829(98)05417-4]. .