Structural studies of lanthanide( III) complexes with oxydiacetic acid andiminodiacetic acid in aqueous solution by EXAFS

The local structure of the trivalent lanthanide (Ln( III)) complexes with o xydiacetic acid (ODA) and iminodiacetic acid (IDA) in aqueous solution was investigated by EXAFS spectroscopy. The coordination number and the bond di stance were obtained by the detailed EXAFS analysis. The coordination numbe r of Ln( III) in both the Ln-ODA and -IDA systems decreases from nine for l ighter Ln( III) to eight for heavier Ln( III). The bond distances of ether O atoms from Ln(III) in the Ln(ODA)(3)(3-) complexes are shorter than those of N atoms in the Ln( IDA)(3)(3-) ones.