Through adding quantitative ammonia into a precursor solution containing stoichiometric quantities of Ba and Sr ions before the co-precipitation procedure, a simple oxalate co-precipitation method based one-step cation-exchange reaction between the stoichiometric solutions of oxalotitanic acid (HTO) and barium+strontium nitrate is investigated successfully for the quantitative precipitation of barium-strontium titanyl oxalate (BSTO): Ba0.6Sr0.4TiO(C2O4)(2)center dot 4H(2)O precursor powders. The pyrolysis of BSTO at 800 degrees C/4h in air produced the homogeneous brain-like shaped barium-strontium titanate (Ba0.6Sr0.4TiO3: BST) powders. The characterization studies were carried on the as-dried BSTO and calcined BST powders by various physicochemical techniques, IR, DSC/TGA, XRD, SEM, etc. It revealed that the BST powders are cubic, stoichiometric, highly pure, sub-micron-sized with nearly uniform size, brain-like shape and agglomerated nature. (c) 2008 Elsevier B.V. All rights reserved.