The thermal decomposition of two inclusion compounds Mn(HCOO)2·1/3C4H8O2 and Mn(HCOO)2·1/3C4H8O was studied in the inert atmosphere. The process of both dioxane, and tetrahydrofurane removal has two steps; the intermediate
phase is unstable and kinetically hindered. Manganese formate is stable up to 330°C. Thermogravimetric data (obtained at different
rates of linear heating) were processed with computer program (with ‘Model free’ approach). Kinetic parameters were calculated
for the first decomposition step, and the process is described by equation of n-order reaction with autocatalysis.