Thermal decomposition of potassium bis-oxalatodiaquaindate( III) monohydrate

Indium (III) is precipitated with oxalic acid in the presence of potassium nitrate maintaining an overall concentration of 0,125 M in HNO3. Chemical analysis of the complex salt obtained indicates the formula, K[In(C2O4)2]3H2O. Thermal decomposition studies show that the compound decomposes first to the anhydrous potassium indium oxalate and then to the final mixture of the oxides through formation of potassium carbonate and indium (III) oxide as intermediates. Isothermal study, X-ray diffraction pattern and IR spectral data support the proposed thermal decomposition mechanism.