Abstract

Pd L-edge XANES and Pd K-edge XANES/EXAFS have been studied to investigate the electronic configuration and local structure of Pd in a new perovskite LaPdO₃, which was prepared under high pressure. A white line in the Pd L-edge XANES for LaPdO₃ is positioned just in the middle of those for divalent (Pd^IIO) and tetravalent (Zn₂Pd^IVO₄) palladates. The peak intensity for LaPdO₃ is also in-between those for PdO and Zn₂PdO₄. Pd K-edge XANES spectra for PdO is characterized by a shoulder in the threshold edge due to the planar square coordination of Pd. The absence of such a shoulder in Pd K-edge XANES spectra for LaPdO₃ and Zn₂Pd^IVO₄ suggests a nearly regular octahedral symmetry of (PdO₆) in both structures. These XANES results underline that the palladium ions with an oxidation state of III are stabilized with the electronic configuration, t_2g⁶σ*¹ in LaPdO₃. The Pd K-edge EXAFS analysis confirms that (PdO₆) octahedra in LaPdO₃ are nearly isotropic and the average Pd^III–O bond distance is 2.06₄ Å, which is compatible with the average Pd^III–F bond distance (2.00 Å) estimated from a recent EXAFS study on trivalent palladium fluoride.