Thermal decomposition behaviour of lanthanum(III) tris-tartrato lanthanate(III) decahydrate

Lanthanum(III) tris-tartrato lanthanate(III) decahydrate, La[La(C4H4O6)3]·10H2O has been synthesized and characterized by elemental analysis, IR, electronic spectral and X-ray powder diffraction studies. Thermal studies (TG, DTG and DTA) in air showed a complex decomposition pattern with the generation of an anhydrous species at ~170°C. The end product was found to be mainly a mixture of La2O3 and carbides at ~970°C through the formation of several intermediates at different temperature. The residual product in DSC study in nitrogen at 670°C is assumed to be a similar mixture generated at 500°C in TG in air. Kinetic parameters, such as, E*, ΔH, ΔS, etc. obtained from DSC are discussed. IR and X-ray powder diffraction studies identified some of the decomposition products. The tentative mechanism for the thermal decomposition in air of the compound is proposed.