Structure of tin phosphate glasses by neutron and X-ray diffraction

被引：12

作者：

Hoppe U. ^{[1
]}

Brow R.K. ^{[2
]}

Hannon A.C. ^{[3
]}

Zimmermann M.V. ^{[4
]}

机构：

[1] Rostock University, Institute of Physics, Rostock

[2] Missouri University of Science and Technology, Department of Materials Science and Engineering, Rolla, 65409, MO

[3] ISIS facility, Rutherford Appleton Laboratory, Chilton, Didcot, OX11 0QX, Oxon

[4] Deutsches Elektronen-Synchrotron DESY, Hamburg

来源：

Journal of Non-Crystalline Solids: X | 2019年 / 2卷

关键词：

Bridging oxygen - Coordination number - Non-bridging oxygen - Oxygen bonds - Scattering vectors - Structural parameter - Structural unit - Trigonal bipyramids - Trigonal pyramids - X- ray diffractions;

D O I：

10.1016/j.nocx.2019.100017

中图分类号：

学科分类号：

摘要：

Neutron and X-ray diffraction experiments with large ranges of scattering vector, up to Qmax of 400 nm−1 and 250 nm−1, respectively, were performed on (SnO)x(P2O5)1-x glasses with 0.5 ≤ x ≤ 0.7, and the structural parameters of the P[sbnd]O and Sn[sbnd]O polyhedra were determined. The fraction of P–NBO (non-bridging oxygen) bonds increases systematically at the expense of the P–BO (bridging oxygen) bonds with SnO additions. The Sn[sbnd]O coordination number decreases in a predictable way from four at the metaphosphate composition (x = 0.5) to about three at the diphosphate composition (x = 0.67). The structural units are assumed to be SnO4 trigonal bipyramids and SnO3 trigonal pyramids with the lone-pair of Sn(II) electrons occupying one of the corners, similar to those in related crystal structures. For all glasses up to x = 0.67, the SnOz pyramids and PO4 tetrahedra form a continuous network with P[sbnd]O[sbnd]P and P[sbnd]O[sbnd]Sn bonds and the Sn[sbnd]O polyhedra do not share oxygen neighbors. From comparisons of the compositional dependences of the Sn[sbnd]O and Zn[sbnd]O coordination numbers and the respective number densities of atoms in the binary tin and zinc phosphate glasses, it is presumed that the Sn[sbnd]O coordination increases further with NSnO > 4 in the ultraphosphate range (x < 0.5). © 2019 The Author(s)

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