X-Ray Diffraction Study on the Local Structure of Molten ErCl₃

Abstract

Abstract The short range structure of molten ErCl 3 at 1053 K was investigated by X-ray diffraction. The nearest neighbour distance of Er 3+ -Cl - and the coordination number of Cl - around Er 3+ were estimated to be 2.63 Å and 5.8 Å, respectively, and the Er 3+ -Er 3+ and Cl - -Cl - distances 4.05 Å and 3.75 Å, respectively. The ratio of the anion-anion pair distance to the cation-anion pair distance (r -- /r+ - ) was, therefore, 1.43, being close to 1.41, characteristic of octahedral geometry. These results indicate that ErCl 6 3- -octahedra exist in molten ErCl 3 . Probably Er2Clio and a small amount of Er2Cl 11 5- ions are formed according to the geometrical calculations of bond lengths and bond angles.