POWDER NEUTRON-DIFFRACTION STUDY OF ZRTIO4, ZR5TI7O24, AND FENB2O6

The zirconium titanates ZrTiO//4 and Zr//5TiO//2//4 and the iron niobate FeNb//2O//6 have been investigated with neutron diffraction powder technique and the Rietveld method. All three compounds crystalize with the symmetry of space group Pbcn and have lattice parameters a equals 4. 8042(2), b equals 5. 4825(3), c equals 5. 0313(2) A for ZrTiO//4; a equals 14. 3574(6), b equals 5. 3247(3), c equals 5. 0200(2) A for Zr//5Ti//7O//2//4; and a equals 14. 2661(2), b equals 5. 7334(1), c equals 5. 0495(1) A for FeNb//2O//6. Pure zirconium titanate, ZrTiO//4, has the alpha -PbO//2-type structure with a random distribution of the two cations.