X-Ray, Electron Diffraction and HREM studies of KHTi4O9, xH2O Thermolysis: Characterization of K4Ti16O34

The structure of the new phase K4Ti16O34 was determined from electron diffrac- tion and high resolution electron microscopy data supported by X-ray and thermogravimetric analysis.K2Ti8O17 obtained from the tetratitanate K2Ti4O9 by a soft chemistry reaction trans- forms at 750 °C into a high temperature form K4Ti16O34.The "cut and projection" method is used to analyze the electron diffraction patterns and to determine the stacking sequences from geometrical feature of the diffraction patterns.The structure deduced from electron diffraction patterns and direct imaging can be described as resulting from a regular intergrowth of two tun- nel titanates: the hexatitanate and an hypothetical decatitanate.As the homologous series of tunnels alkali titanates A2TimO2m+1 with m > 6, the structure is derived from the lepidocrocite archetype.The formation mechanism of the regular block sequence is discussed.Microsc.Microanal.Microstruct.