Formation and decomposition of the rutile-type compound FeSbO4. TG-DTA Study

The reaction between Fe2O3 (hematite) and Sb2O3 leading to the formation of the rutile-type compound FeSbO4 was analysed by means of DTA and TG, performed under various O2 partial pressures up to 1673 K. The reaction products were identified by means of XRD analysis. Three transformations occur in the analysed temperature range: 1. oxidation of Sb2O3 to Sb2O4 between 745 and 768 K; 2. formation of FeSbO4 between 1226 and 1246 K; 3. decomposition of FeSbO4 without melting above 1543-1591 K. The TG-DTA and XRD analysis results indicate that deviations from perfect stoichiometry are likely to exist inside FeSbO4.