• Gammond, Lawrence
• Vaughan, Gavin
• Silva, Rita Mendes Da
• Mohammadi, Hesameddin
• Salmon, Philip Stephen
• Youngman, Randall
• Aitken, Bruce
• Hannon, Alex
• Zeidler, Anita
• Giron Lange, Esther

Abstract

<jats:p>The structure of zinc aluminosilicate glasses with the composition (ZnO)x(Al2O3)y(SiO2)1−x−y, where 0 ≤ x &amp;lt; 1, 0 ≤ y &amp;lt; 1, and x + y &amp;lt; 1, was investigated over a wide composition range by combining neutron and high-energy x-ray diffraction with 27Al magic angle spinning nuclear magnetic resonance spectroscopy. The results were interpreted using an analytical model for the composition-dependent structure in which the zinc ions do not act as network formers. Four-coordinated aluminum atoms were found to be in the majority for all the investigated glasses, with five-coordinated aluminum atoms as the main minority species. Mean Al–O bond distances of 1.764(5) and 1.855(5) Å were obtained for the four- and five-coordinated aluminum atoms, respectively. The coordination environment of zinc was not observed to be invariant. Instead, it is dependent on whether zinc plays a predominantly network-modifying or charge-compensating role and, therefore, varies systematically with the glass composition. The Zn–O coordination number and bond distance were found to be 4.36(9) and 2.00(1) Å, respectively, for the network-modifying role vs 5.96(10) and 2.08(1) Å, respectively, for the charge-compensating role. The more open coordination environment of the charge-compensator is related to an enhanced probability of zinc finding bridging oxygen atoms as nearest-neighbors, reflecting a change in the connectivity of the glass network comprising four-coordinated silicon and aluminum atoms as the alumina content is increased.</jats:p>

Topics

• impedance spectroscopy
• x-ray diffraction
• Oxygen
• aluminium
• zinc
• glass
• glass
• Silicon
• Nuclear Magnetic Resonance spectroscopy
• spinning