The TG/DSC curves of K-3[Cr(C2O4)(3)](.)3H(2)O, K-3[Al(C2O4)(3)](.)3H(2)O, K-3[Fe(C2O4)(3)](.)3H(2)O and K-2[Cu(C2O4)(2)](.)2H(2)O in nitrogen were determined at the heating rate of 15, 10, 5, and 2 degreesC min(-1), respectively. A non-linear optimization was applied for different reaction models to perform single and overall steps optimizations. Kinetic parameters were given, and the most probable mechanism functions were suggested. (C) 2003 Elsevier B.V. All rights reserved.