Figure 12
Schematic diagram of the doubled monoclinic unit cell showing superposition of anti-phase rotation of octahedra (about [001] direction) and other atoms, i.e. O(1), O(2), Pb(1), Pb(2), Zr/Ti(1) and Zr/Ti(2), displaced as in the Cm space-group model. The open circles, filled big circles and filled small circles represent O, Pb and Zr/Ti atoms, respectively. The arrows indicate the sense of displacements from their respective undisplaced position (after Ranjan et al., 2002). |