Title

Multinuclear MAS NMR Study of the Short-Range Structure of Fluorophosphate Glass

Abstract

We have examined the bonding arrangements in Na-P-O-F and Na-Al-P-O-F glasses using 19F, 27Al, and 31P solid-state magic angle spinning nuclear magnetic resonance (MAS NMR) spectroscopy. For the Al-free series of glasses, the 19F NMR spectra are dominated by peaks near +90 ppm, representative of F terminating P-chains. The formation of these bonds has little effect on the 31P chemical shifts, indicating that F preferentially replaces bridging oxygen on the phosphate tetrahedra, consistent with previous NMR studies of crystalline fluorophosphates and other spectroscopic studies of fluorophosphate glass. For the Na-Al-P-O-F glasses, 27Al NMR detects only octahedral Al-sites, the 19F NMR spectra include a second peak near -12 ppm due to F bonded to Al, and the 31P NMR spectra contain signals due to Q1-sites with one or more Al next-nearest neighbors. The relative intensity of the two 19F peaks correlates well with previous spectroscopic studies and shows that a greater fraction of F-P bonds forms when the base glass is remelted in NH4HF2.

Department(s)

Materials Science and Engineering

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 1992 Materials Research Society, All rights reserved.


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