TY  - JOUR
AU  - Hoppe, Uwe
AU  - Saitoh, Akira
AU  - Tricot, Grégory
AU  - Freudenberger, Parker
AU  - Hannon, Alex C.
AU  - Takebe, Hiromichi
AU  - Brow, Richard K.
TI  - The structure and properties of xZnO–(67− x )SnO–33P<sub>2</sub>O<sub>5</sub> glasses: (II) Diffraction, NMR, and chromatographic studies
JO  - Journal of non-crystalline solids
VL  - 492
SN  - 0022-3093
CY  - Amsterdam [u.a.]
PB  - Elsevier Science
M1  - PUBDB-2018-03287
SP  - 68 - 76
PY  - 2018
N1  - © Elsevier B.V.; Post referee fulltext in progress; Embargo 12 months from publication
AB  - Glasses with nominal molar compositions xZnO–(67− x )SnO–33P<sub>2</sub>O<sub>5</sub> were prepared and their structures were determined by <sup>31</sup>P MAS-NMR spectroscopy, HPLC, and by X-ray and neutron diffraction. Compositional dependent changes in the thermal and optical properties described in Part I of this study are attributed to changes in the coordination environments of Sn<sup>2+</sup>- and Zn<sup>2+</sup>-ions and their effects on the phosphate anionic network. The <sup>31</sup>P MAS-NMR and HPLC data reveal broader distributions of P-tetrahedra in glasses with greater ZnO-contents, due to disproportionation reactions of diphosphate anions in the glass melts to form isolated monophosphate anions and larger triphosphate anions, and due to the loss of some phosphate during glass preparation. The diffraction experiments reveal that Zn<sup>2+</sup> prefers tetrahedral coordination, whereas Sn<sup>2+</sup> is initially incorporated in isolated, three-coordinated sites that convert to four-coordinated sites with greater ZnO contents. These four-coordinated sites must share corners when incorporated into the glass structure and the transition from glasses dominated by isolated SnO<sub>3</sub> pyramids to those with subnetworks of (Sn, Zn)O<sub>4</sub> polyhedra occurs near x = 20, and is reflected by breaks in the composition-property trends. The second break in properties occurs near x = 40, and reflects both the dominance of the ZnO<sub>4</sub> units in the metal subnetwork, as well an increase in the relative numbers of monophosphate anions in the glass structure.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000433647300010
DO  - DOI:10.1016/j.jnoncrysol.2018.04.017
UR  - https://bib-pubdb1.desy.de/record/409108
ER  -