Analysis of thermodynamic and kinetic stabilities in the thermal decomposition of the trinuclear μ-oxoacetates Fe 2 III MIIO(CH3OO)6(H2O)5, with M=Mn,Fe, Co or Ni

The thermal analysis of acetate clusters of general formula Fe ₂ ^III M^IIO(CH₃COO)₆(H₂O)₃]·2H₂O, with M=Mn, Fe, Co or Ni, was performed in dynamic and quasi-isothermal regimes. The thermal decompositions of these compounds proceed in the interval 40–310° and consist of two endothermic and three exothermic stages. Dependence on the nature of the transition metal M is evidenced most explicitly in the parameters of the second stage, proceeding in the interval 103–170°. For this stage the sequences of thermodynamic stability and kinetic stability were established. The effect of the nature of the metal on the thermodynamic and kinetic parameters of the thermal decomposition processes involving the heteronuclear acetates was analyzed. Mechanisms for the first two stages of thermal decomposition are suggested.