The use of X-ray phase diffraction and DTA methods has allowed studies on the interaction of the oxides Sb2O3 and Fe2O3, taking place in the solid state and in the medium of ambient air. The experimental results have shown that the reaction yields the FeSbO4 phase - recently produced by other workers using only co-precipitation methods. The compound has also been obtained from a reaction of alpha-Sb2O4 with Fe2O3.