In this study, Fe0.4Ti0.2-xSnxNb0.4O2 solid solutions have been synthesized from both ceramic and gel colloidal methods from Fe2O3, Nb2O5, TiO2, SnCl2.2H(2)O and FeCl3, NbCl5, TiCl4, SnCl2.2H(2)O respectively. Two kinds of solid solutions with orthorhombic and tetragonal FeNbO4 structures have been obtained. The results indicate that solid solutions structure depends on firing temperature, composition, i. e. Ti/Sn ratio and synthesis method. The optimal composition range to obtain solid solutions with low temperature structures (monoclinic and orthorhombic) is 0.10 less than or equal to x less than or equal to 0.15, but only in samples prepared by colloidal gel method, a single phase with these structures is obtained (900-1100 degrees C). Solid solutions with tetragonal structure are stable at high temperature and a single phase with this structure is obtained at 1300 degrees C in samples with x < 0.10.