Polytitanates in the TiO2-rich side of the phase diagram of BaO-TiO2 system play a major role as microwave dielectric ceramics. The present study aims at synthesis of polytitanates through carbonate-gel route and to re-look at the formation mechanism of Ba2Ti9O20 (2:9). Apart from 2:9, closely related materials such as BaTi4O9 (1:4), BaTi5O11 (1:5), Ba4Ti13O30 (4:13) and Ba6Ti17O40 (6:17) were also synthesized. Besides 2:9, phases that are richer in TiO2 as well as those richer in barium form as single-phase. These results point to the fact that nucleation and surface energy are the critical factor for the formation of 2:9 materials as single-phase ceramic, rather than diffusion. (c) 2005 Elsevier Ltd. All rights reserved.