High-energy EXAFS study of molten GdCl3 systems

The local structure of molten GdCl3 and its mixture in LiCl-KCl eutectic was investigated by Gd K-edge extended X-ray absorption fine structure (EXAFS) technique. As the result of curve fitting analysis, the nearest Gd3 +-Cl− distance was 2.74 ± 0.02 Å with coordination number 6.5 ± 0.3 in the pure melt. On the other hand, those in the 10% GdCl3 mixture melt decreased to 2.70 ± 0.01 Å and 6.1 ± 0.3, respectively. These results suggest that octahedral coordination (GdCl6)3 − structure is formed and stabilized by mixing with the alkali chlorides. The result was compared with that of YCl3 and LaCl3 in LiCl-KCl eutectic melt.