The crystal structure of the ferroelectric phase of Pb5Ge3O11

Abstract

The oxygen positions and structure determined for PbsGe3O11 by Iwata, Koizumi, Koyano, Shibuya and Niizeki (J. Phys. Soc. Japan 35, 314 (1973)) have been confirmed by an independent refinement of 300 neutron reflections collected at the Puerto Rico Nuclear Center using isotropic temperature parameters and a full matrix least squares. It is noted that short lead-oxygen distances and lead site geometry is similar to that found in lead oxides. Germanium takes on its usual tetrahedral coordination. Polarization reversal (and enantiomorphism may be described by the movement of lead atoms and rotations plus slight translations of GeO4 tetrahedra to maintain the strong chemical bonds.