A multi-technique structural study of the tellurium borate glass system
Barney, Emma R., Hannon, Alex C. and Holland, D. (2009) A multi-technique structural study of the tellurium borate glass system. Physics and Chemistry of Glasses - European Journal of Glass Science and Technology Part B, Vol.50 (No.3). pp. 156-164. ISSN 1753-3562Full text not available from this repository.
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A series of tellurium borate, xTeO(2)center dot(100-x)B2O3, glasses has been studied using neutron diffraction, B-11 nuclear magnetic resonance (NMR), Raman spectroscopy and density measurements to investigate how the environments of tellurium and boron change with composition. It was necessary to determine the sample composition by quantitative NMR, after which B-11 NMR and neutron diffraction gave good agreement for the B-O coordination number. The effects of phase separation were studied by making samples with compositions above and below the reported low TeO2 limit of single phase glass formation, 74 mol% TeO2. It was found that samples prepared with 70 mol% TeO2 or less were phase separated, with a clear glass component of composition similar to 80 mol% TeO2. A linear relationship was established between the density and the fraction of four-coordinated boron, N-4, and previous literature data also support this relationship. However, the previous data have glass compositions Which are inconsistent with the present study, and the current work shows that the previous compositions are incorrect, highlighting the problems of phase separation and the importance of careful compositional analysis. With the addition of 13203, no shift in the primary Te-O bond length to shorter distances, such as is seen in alkali tellurites, is observed. The measured Te-O coordination number decreased with the addition of B2O3, due to a reduction in the number of longer Te-O bonds, indicating that the total number of [TeO4] units decreases, to be replaced by [TeO3] units. The range over which the Te-O distribution was measured was limited by the presence of the O-B-O-B peak. Therefore, though the observed tellurium coordination numbers are smaller than predicted by a literature model for the structure of these glasses, further work is needed to determine the full extent of the Te-O distribution which overlaps with the O-O peaks.
|Item Type:||Journal Item|
|Subjects:||Q Science > QD Chemistry
T Technology > TP Chemical technology
|Divisions:||Faculty of Science > Physics|
|Journal or Publication Title:||Physics and Chemistry of Glasses - European Journal of Glass Science and Technology Part B|
|Publisher:||Society of Glass Technology|
|Number of Pages:||9|
|Page Range:||pp. 156-164|
|Access rights to Published version:||Restricted or Subscription Access|
|Funder:||Engineering and Physical Sciences Research Council (EPSRC), Centre for Materials Physics and Chemistry|
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