Similar preservation of the closed-packed layers is observed in titanates. Ba6Ti17O40 and BaTiO3 have closed packed layers containing both barium and oxygen ions. The packing sequences are hexagonal in Ba6Ti17O40 (Hofmeister et al., 1984) and cubic in BaTiO3. Platelike Ba6Ti17O40 particles with the [001] direction perpendicular to the plate face (the crystal structure of Ba6Ti17O40 is monoclinic) are obtained by the reaction of BaTiO3 and TiO2 in NaCl (Kimura et al., 2005), and they are converted into platelike BaTiO3 particles with [111] perpendicular to the plate face by the reaction with BaCO3 in NaCl (Sato & Kimura, 2008). In this case, the obtained platelike BaTiO3 particles are polycrystals.