TY  - JOUR
AU  - Hoppe, U.
AU  - Brow, R. K.
AU  - Hannon, A. C.
AU  - von Zimmermann, Martin
TI  - Structure of tin phosphate glasses by neutron and X-ray diffraction
JO  - Journal of non-crystalline solids
VL  - 2
SN  - 0022-3093
CY  - Amsterdam [u.a.]
PB  - Elsevier Science
M1  - PUBDB-2019-01769
SP  - 100017 
PY  - 2019
AB  - Neutron and X-ray diffraction experiments with large ranges of scattering vector, up to Q<sub>max</sub> of 400 nm<sup>−1</sup> and 250 nm<sup>−1</sup>, respectively, were performed on (SnO)<sub>x</sub>(P<sub>2</sub>O5)<sub>1−x</sub> glasses with 0.5 ≤ x ≤ 0.7, and the structural parameters of the PO and SnO 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 SnO 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 SnO<sub>4</sub> trigonal bipyramids and SnO<sub>3</sub> 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 PO<sub>4</sub> tetrahedra form a continuous network with POP and POSn bonds and the SnO polyhedra do not share oxygen neighbors. From comparisons of the compositional dependences of the SnO and ZnO coordination numbers and the respective number densities of atoms in the binary tin and zinc phosphate glasses, it is presumed that the SnO coordination increases further with N<sub>SnO</sub> > 4 in the ultraphosphate range (x < 0.5). 
LB  - PUB:(DE-HGF)16
DO  - DOI:10.1016/j.nocx.2019.100017
UR  - https://bib-pubdb1.desy.de/record/420926
ER  -