Single phase BaFe12O13 ferrite identified by X-ray diffraction and Raman spectroscopy has been successfully synthesized using Fe(NO3)(3)center dot 9H(2)O and Ba(NO3)(2) as starting materials and NaOH as a precipitant via a modified one-step hydrothermal approach which involves the elimination of carbonate radicals from reaction system based on the stoichiometric ratio of [Ba2+]/[Fe3+]. Hydrothermal products under various synthetic conditions were studied, including different addition amounts of Ba(NO3)(2) in the modified operation, reaction temperatures and times, and hydroxyl concentrations. The BaFe12O19 particles featuring an excellent hexagonal plates shape can be hydrothermally synthesized with the aid of polyethylene glycol. It has been found that the presence of alpha-Fe2O3 in a traditional hydrothermal process is motivated by the deviation from the desired [Ba2+]/[Fe3+] ratio caused by the negligent precipitation of Ba2+ ions to BaCO3. An investigation on the preferred hydrothermal product through thermodynamic calculation shows that the reduction in Gibbs free energy for the exclusive formation of BaFe12O19 with 1 mol of Fe3+ ions at 220 degrees C is approximately 32 kJ higher than that for the complete transformation to alpha-Fe2O3 with an equal consumption quantity of Fe3+ ions. (C) 2016 Elsevier B.V. All rights reserved.