A ferroelectric barium titanate, BaTi2O5.

The crystal structure of monobarium dititanium pentaoxide, BaTi(2)O(5), synthesized by a floating-zone method, was studied by X-ray diffraction. Previous reports describe the structure as being in the monoclinic centrosymmetric space group C2/m. We have recently found that this material exhibits ferroelectricity, and therefore BaTi(2)O(5) should have lower symmetry. The crystal structure of BaTi(2)O(5) was refined in space group C2, revealing a displacement of the Ti atoms along the b axis. This result is consistent with the fact that the ferroelectricity of BaTi(2)O(5) was only observed along the b axis.