PREPARATION, CRYSTAL-STRUCTURE AND ELECTRON-MICROSCOPIC INVESTIGATIONS OF PR2TI3O8CL2

Pr2Ti3O8Cl2 was prepared by chemical transport and investigated by X-ray diffraction and electron microscopical techniques. The single crystal structure investigation shows that Pr2Ti3O8Cl2 is isotypic with Nd2Ti3O8Cl2: space group Pbcn (No. 60) with a = 14.6542(47) angstrom, b = 11.6161(52) angstrom, c = 5.0433(10) angstrom (diffractometer data), Z = 4. Least-squares refinement based on 1076 independent reflections led to an R value of 4.56%. Main building units are TiO6-octahedra and Pr(Cl3O)O4 square antiprisms. Efforts to obtain Ln2Ti3O8Cl2 (Ln = La,Ce) by chemical transport reaction failed. Electron diffraction and high resolution transmission electron microscopy images of Pr2Ti3O8Cl2 along the [001] direction were obtained. They could be interpreted by comparing them with images calculated on the basis of the multi slice method.