Mössbauer study of the thermal decomposition of iron(III) benzoate and iron(III) fumarate

The thermal decomposition of iron(III) benzoate, Fe(C₇H₅O₂)₃, and iron(III) fumarate pentahydrate, Fe₂(C₄H₂O₄)₃ 5 H₂O, containing uni- and bidentate ligands, respectively, has been investigated at various temperatures for different intervals of time in a static air atmosphere. Thermolysis of these compounds leads directly to the formation of α-Fe₂O₃ in the case of iron(III) benzoate and Fe₃O₄ in the case of iron(III) fumarate as the ultimate products, thus without undergoing reduction to the iron(II) state.