The F-7(o) --> D-5(o) excitation spectra of Eu(III) complexed with picolinic acid were investigated using Eu(III) excitation spectroscopy. Six overlapping peaks are seen in the excitation spectra, indicating the formation of six species. The structures of the six species are proposed here and described in terms of both coordination by carboxylate and N-chelation. (C) 1999 Academic Press.