Melting in Trivalent Metal Chlorides

Abstract

We report a neutron diffraction study of the liquid structure of YCl3 and combine the structural data with macroscopic melting and transport data to contrast the behaviour of this molten salt with those of SrCl2, ZnCl2 and AlCl3 as prototypes of different melting mechanisms for ionic materials. A novel melting mechanism for trivalent metal chlorides, leading to a loose disordered network of edge-sharing octahedral units in the liquid phase, is thereby established. The various melting behaviours are related to bonding character with the help of Pettifor's phenomenological chemical scale.