SHORT-RANGE ORDER IN KPO3 GLASS STUDIED BY NEUTRON AND X-RAY-DIFFRACTION

The short-range order of KPO3 glass has been studied by diffraction me thods in order to make evident the different behaviour of the P-O bond s within the PO4 tetrahedron. The oxygen sites are devided into bridgi ng and terminal (non-bridging) oxygen sites, corresponding to two P-O bond lengths, the difference of which amounts to 14.5 pm. Previous con clusions about the changes of the P-O bond lengths under the influence of modifier cations of different electric field strength are corrobor ated. The K-O environments reveal two apparently different distances r (KO) with equal contributions to the total K-O coordination number of about 6.7. To explain this phenomenon, the K+ cations are suggested to be located in non-spherical cavities.