Polycrystalline spherical Bi 0:5 Na 0:5 TiO 3 (BNT) particles with narrow size distributions were obtained by the gel-sol method, where the precursory gel was composed of BiX 3 (X ¼ OH, NO 3 ), NaOH, and stable Ti 4þ complex which was prepared by mixing Ti(i-C 3 H 7 O) 4 with triethanolamine to inhibit the uncontrolled hydrolysis in aqueous solution. The resulting morphology was readily controlled as single-crystalline rod-like and tubular shapes with the simple tuning of the Bi/Ti molar ratios in the presence of NaClO 4
