Toward a Structural Model for the Aluminum Tellurite Glass System

Barney, Emma; Laorodphan, Nattapol; Mohd-Noor, Faizani; Holland, Diane; Kemp, Tom; Iuga, Dinu; Dupree, Ray

Abstract

Neutron diffraction, 27Al MAS NMR, and 27Al Double Quantum MAS NMR results are presented and analyzed to determine the local environments of the cations in a series of aluminum tellurite glasses. Total scattering results show that, within a maximum Te–O distance of 2.36 Å, tellurium exhibits a mix of [TeO3E] and [TeO4E] environments (E = electron lone-pair), with a linear reduction in the average tellurium–oxygen coordination number as Al2O3 is added to the glass. This is accompanied by a linear decrease in the average aluminum–oxygen coordination number as [AlO4] units form at the expense of [AlO6] units, while the fraction of [AlO5] units remains roughly constant. A consideration of the bonding requirements of the five structural units in the glass, [TeO3E], [TeO4E], [AlO4], [AlO5], and [AlO6], has allowed a direct quantitative relationship between tellurium–oxygen and aluminum–oxygen coordination numbers to be derived for the first time, and this has been successfully extended to the boron tellurite system. Double Quantum 27Al MAS NMR indicates that, in contrast to previous reports, the shortest Al...Al separations are significantly smaller (∼3.2 Å) than expected for a uniform distribution and there is a preference for [AlO6]–[AlO6] and [AlO4]–[AlO4] corner sharing polyhedra. These associations support a new structural model which successfully applies the principle of charge balance to describe the interaction of tellurium and aluminum and identifies and explains the clustering of [AlOn] polyhedra in the glass and their preferred associations. [AlO6] and [TeO4E] units dominate the network in TeO2-rich glasses and [AlO4]− units form to stabilize the [TeO3E]+ units as alumina is added to the glass.

Citation

Barney, E., Laorodphan, N., Mohd-Noor, F., Holland, D., Kemp, T., Iuga, D., & Dupree, R. (2020). Toward a Structural Model for the Aluminum Tellurite Glass System. Journal of Physical Chemistry C, 124(37), 20516–20529. https://doi.org/10.1021/acs.jpcc.0c04342

• Journal Article Type: Article
• Acceptance Date: Aug 19, 2020
• Online Publication Date: Aug 21, 2020
• Publication Date: Sep 17, 2020
• Deposit Date: Sep 24, 2020
• Publicly Available Date: Aug 22, 2021
• Journal: The Journal of Physical Chemistry C
• Print ISSN: 1932-7447
• Electronic ISSN: 1932-7455
• Peer Reviewed: Peer Reviewed
• Volume: 124
• Issue: 37
• Pages: 20516–20529
• DOI: https://doi.org/10.1021/acs.jpcc.0c04342
• Keywords: General Energy; Physical and Theoretical Chemistry; Electronic, Optical and Magnetic Materials; Surfaces, Coatings and Films
• Public URL: https://nottingham-repository.worktribe.com/output/4901745
• Publisher URL: https://pubs.acs.org/doi/pdf/10.1021/acs.jpcc.0c04342
• Additional Information: This document is the Accepted Manuscript version of a Published Work that appeared in final form in [JournalTitle], copyright © 2020 American Chemical Society after peer review and technical editing by t he publisher. To access the final edited and published work see https://pubs.acs.org/doi/pdf/10.1021/acs.jpcc.0c04342