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

Abstract

Abstract The short range structure of molten ErCl3 at 1053 K was investigated by X-ray diffraction. The nearest neighbour distance of Er3+-Cl- and the coordination number of Cl- around Er3+ were estimated to be 2.63 Å and 5.8 Å, respectively, and the Er3+-Er3+ 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 ErCl6 3--octahedra exist in molten ErCl3. Probably Er2Clio and a small amount of Er2Cl11 5- ions are formed according to the geometrical calculations of bond lengths and bond angles.