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 methods in order to make evident the different behaviour of the P-O bonds within the PO4 tetrahedron. The oxygen sites are devided into bridging and terminal (non-bridging) oxygen sites, corresponding to two P-O bond lengths, the difference of which amounts to 14.5 pm. Previous conclusions about the changes of the P-O bond lengths under the influence of modifier cations of different electric field strength are corroborated. 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.