Study on the transformation from NaCl-type Na2TiO3 to layered titanate

NaCl-type crystal structure sodium titanate (Na2TiO3), which exhibits a unit cell parameter of a=4.49 Å, was obtained by high temperature molten salt reaction. An intermediate phase product with layered structure was prepared by leaching the obtained Na2TiO3. We propose that the layered titanate structure is composed of Na2TiO3 and H2O, corresponding to the host-layer and guest-substance, respectively. Furthermore, the crystal structures of layered titanate were optimized by the density functional theory (DFT). This indicates that water molecules are distributed in an orderly manner in the interlayer through the formation of hydrogen-bonded chain. Moreover, the position of the adjacent lamella translates to c/2 along the c-axis after the intercalation of water.

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► Ti4+ and Na+ ion occupy the same position in unit cell of NaCl-type Na2TiO3.
► Na+ is part of host-layer when layered titanate is obtained from NaCl-type Na2TiO3.
► A first-principles prediction of ideal layered titante structure.