Thermal decomposition of a molecular material {N(n-C4H9)4[FeIIFeIII(C2O4)3]}∞ leading to ferrite: A reaction kinetics study

A multi-step thermal decomposition of a molecular precursor, {N(n-C4H9)4[FeIIFeIII(C2O4)3}∞ has been studied using non-isothermal thermogravimetry (TG) measurements in the temperature range 300 to ~800 K at multiple heating rates (5, 10 and 20 K min-1). The thermal decomposition of the oxalate-based complex proceeds stepwise through a series of intermediate reactions. Two different isoconversional methods, namely, improved iterative method and model-free method are employed to evaluate the kinetic parameters: activation energy and rate of reaction, and the most probable reaction mechanism of thermal decomposition is also determined. The different reaction pathways leading to different steps in the TG profile have also been explored which are supplemented by earlier experimental observations of the present authors.