Some mixed ligands complexes of rare earth elements with benzoate and 1,10-phenantroline withthe general formula [Ln(Bez)3(Phen)].2H2O (Ln: La, Nd, Sm
Bez-: benzoate
Phen: 1,10-phenantroline) have been prepared. The characterization of these complexes have beeninvestigated by IR, thermal analysis and mass-spectroscopy methods. The coordination modes of theligands to Ln(III) centres have been investigated by IR spectra. Mass-spectroscopy showed that thecomplexes are monomes. TG- curves indicate that the complexes are unstable temperature. Thethermal separation of the complexes was supposed as follows: