Four complexes of Ln (III) (Ln: Nd, Sm, Eu, Gd) with mixed ligands (benzoic and 2,2’-dipyridine-Noxide) have been synthesised. They have general formula is Ln(Benz)2(DipyO)(H2O)2 (Ln: Nd, Sm, Eu, Gd
Benz-: Benzoate, DipyO: 2,2’-dipyridine-N-oxide). The characterization of these complexes have been studied by IR, thermal analysis and mass-spectroscopy methods. IR spectra suggest that complexes have been synthesized successfully. The coordination modes of the ligands to Ln(III) centres have been investigated by IR spectra. Mass-spectroscopy showed that the complexes are monomers and they are stable. The thermal analysis indicates that they are all quite stable to heat