X-Ray absorption spectroscopic study on LaPdO3

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 (PdIIO) and tetravalent (Zn2PdIVO4) 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 Zn2PdIVO4 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, t2g6σ*1 in LaPdO3. The Pd K-edge EXAFS analysis confirms that (PdO6) octahedra in LaPdO3 are nearly isotropic and the average PdIII–O bond distance is 2.064 Å, which is compatible with the average PdIII–F bond distance (2.00 Å) estimated from a recent EXAFS study on trivalent palladium fluoride.