Abstract
Ternary lanthanide iridium oxides Ln3IrO7 (Ln=Pr, Nd, Sm, and Eu) were prepared and their structures were determined by X-ray diffraction measurements. At room temperature, Pr3IrO7 crystallizes in an orthorhombic superstructure of cubic fluorite with the space group Cmcm. The results of the differential thermal analysis (DTA) and specific heat measurements show the existence of a phase transition for Ln3IrO7 (Ln=Pr, Nd, Sm, and Eu) at 262, 342, 420, and 485 K, respectively. At low temperatures, Ln3IrO7 crystallizes in a monoclinic structure with the space group P21/n. These results for Ln3IrO7 are compared with those for Ln3MoO7, Ln3RuO7, Ln3ReO7, and Ln3OsO7.
