Journal of Analytical and Applied Pyrolysis 62 (2002) 205–214 www.elsevier.com/locate/jaap Thermal decomposition of iron(II) oxalate – magnesium oxalate mixtures El-H.M. Diefallah *, M.A. Mousa, A.A. El-Bellihi, E.-H. El-Mossalamy, G.A. El-Sayed, M.A. Gabal Department of Chemistry, Zagazig Uniersity, Benha -Branch, Benha, Egypt Received 15 September 2000; accepted 4 January 2001 Abstract The thermal decomposition of iron(II) oxalate – magnesium oxalate mixture (2:1 mole ratio) was investigated using DTA-TG, XRD and Mo ¨ ssbauer effect measurements. The decomposition of the anhydrous oxalate mixture proceeds in two steps and kinetic analysis of the two steps were performed under non-isothermal conditions using different integral methods of analysis. Integral composite analysis of data showed that the decomposition reactions are best described by the three-phase boundary, R 3 model. Kinetic analysis of data were also carried out in accordance with the methods of Ozawa and Coats-Redfern and the results are discussed in comparison with the composite analysis of data. Mo ¨ ssbauer spectra of samples calcined at different temperatures are discussed and show that in the early stages of the decomposition at about 300 °C, part of the Fe(III) oxide is formed in superamagnetic doublet state. As the temperature is increased, supermagnetism disappears. The results of XRD analyses are in accordance with the results of the Mo ¨ ssbauer effect and show that magnesium ferrite forms in samples heated at higher temperatures. © 2002 Elsevier Science B.V. All rights reserved. Keywords: Decomposition; Thermal analysis; Mo ¨ ssbauer; Magnesium oxalate; Iron(II) oxalate 1. Introduction Chemical reactions between solids are of considerable importance in the technol- ogy of materials processing. Thermal analysis plays an important role in the determination and identification of materials, change in phase, thermal dehydration * Corresponding author. 0165-2370/02/$ - see front matter © 2002 Elsevier Science B.V. All rights reserved. PII: S0165-2370(01)00117-6