Abstract
The thermal decomposition of ferrous oxalate dihydrate FeC2O4.2H2O, has been investigated using thermogravimetric (TG), differential thermogravimetric (DTG), differential thermal analysis (DTA), X-ray diffraction and infra-red spectroscopic techniques.
The DTA data obtained in air consist of an endothermic dehydration peak at ∼ 190‡ C and two exothermic peaks at ∼ 245 and ∼ 360‡ C. The first exotherm corresponds to the primary oxidative decomposition while the second one seems to be due to a structural transformation from a disordered or non-crystalline to a crystalline state ofα-Fe2O3. Similar experiments carried out using a nitrogen atmosphere show an endothermic peak ∼ 190‡ C followed immediately by an exothermic peak at 240‡ C. The final product of this decomposition has been identified as Fe3O4.
The oxalate dihydrate containing traces of moisture decomposes in air under the ambient of its own gaseous products at ∼ 300‡ C to giveγ-Fe2O3. This compound has been characterized by X-ray diffraction and magnetic hysteresis measurements.
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Rao, V., Shashimohan, A.L. & Biswas, A.B. Studies on the formation of γ-Fe2O3 (maghemite) by thermal decomposition of ferrous oxalate dihydrate. J Mater Sci 9, 430–433 (1974). https://doi.org/10.1007/BF00737843
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DOI: https://doi.org/10.1007/BF00737843