THERMAL-DECOMPOSITION STUDY OF [MCU(C3H2O4)(2)(H2O)(N)] PHASES (M IS CA (N=3), SR AND BA (N=4))

Three new compounds with the general formula [MCu(C3H2O4)(2)(H2O)(n)] (M is Ca (n = 3), Sr and Ba (n = 4)) have been synthesized and charact erized by analytical and infrared techniques. X-ray diffraction method s have shown that all the complexes have orthorhombic unit cells. Ther mal decomposition of these compounds using TGA-DSC and DTA techniques involves three consecutive steps: dehydration, ligand pyrolysis and in organic residue evolution. Dehydration is an endothermic process with enthalpies of around 200 kJ mol(-1). Kinetic analysis of the dehydrati on curves has been performed and the Johnson equation gave the best co rrelation factors for the three complexes. Further treatments in tubul ar furnaces resulted in the formation of mixed oxides of formula MCuO( 2) (M is Ca, Sr and Ba). The formation of small homogeneous particles in these oxides, as with metallo-organic percursors, has been observed by scanning electron microscopy.