Thermal decomposition study of erbium oxalate hexahydrate

The thermal decomposition of erbium oxalate hydrate (Er-2(C2O4)(3).6H(2)O) till 900 degrees C, in air and nitrogen, is investigated by nonisothermal g ravimetry and differential thermal analyses. The activation energy (Delta E ) is determined for each thermal decomposition step. The gaseous decomposit ion products are identified by infrared (IR)-spectroscopy. Intermediate and final solid products are characterized by IR-spectroscopy and X-ray diffra ction (XRD). The results indicate that, in air atmosphere, following a step wise dehydration at 90-370 degrees C, the anhydrous product was noncrystall ine and thermally unstable. An oxycarbonate Er2O2CO3 is Obtained at 450 deg rees C which decomposes near 600 degrees C into crystalline Er2O3- The atmo sphere has no affect on the decomposition pathway. The oxide proportion and crystailinity improved on increasing the temperature to 800 degrees C. The volatile decomposition products were water vapor and carbon oxides. (C) 20 00 Elsevier Science B.V. All rights reserved.