Structural changes in Fe-doped SrSn[O.sub.3] perovskites during thermal analysis

Perovskite-type strontium stannate, SrSn[O.sub.3], is of technological interest because of its potential applications. In the present work, Fe(III)-doped SrSn[O.sub.3] perovskites were synthesized using Sn metal and the polymeric precursor method, derived from the Pechini method. Thermogravimetric evaluations in [N.sub.2] and [O.sub.2] atmospheres were performed to evaluate the possible formation of oxygen vacancies resulting from Fe(III) doping. The X-ray diffraction patterns showed the formation of an orthorhombic structure with high crystallinity after calcination at 1,073 K. The first thermal analysis, in a [N.sub.2] atmosphere, led to the partial elimination of strontium carbonate and hydroxyl groups, while the thermal analysis in an [O.sub.2] atmosphere led to an increase in the mass, indicating [O.sub.2] adsorption on the lattice, which could be related to the presence of Fe(III) and Fe(IV) in the perovskite structure. Moreover, the thermal analysis changed the symmetry of the iron-doped perovskites.