Two complexes were isolated from aqueous Pd(NO3)(2)-Na(2)H(2)EDTA solutions and studied by single crystal X-ray diffraction, IR/Raman spectroscopy, and photoelectron spectroscopy. The first complex, Pd(Hkpda)(2) (kpda = ketopiperazinediacetate dianion, C8H10N2O5). forms yellow parallelepipeds during slow evaporation of Pd(NO3)(2)-Na(2)HEDTA solution at 25degreesC, and is a result of EDTA oxidation. The second one, [Pd(mu-H(2)EDTA)](2) . 2NaNO(3) . 7.5H(2)O, with two EDTA molecules acting as bridges between two palladium atoms, forms yellow bipyramides during fast evaporation at 60degreesC. In both complexes, the palladium atoms adopt a planar trans-geometry by bonding to two nitrogen and two oxygen atoms of two ligand molecules. (C) 2004 Elsevier B.V. All rights reserved.