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Updated: Jun 23, 2026
14:55
Atomic Scale Structural Studies of Macromolecular Assemblies by Solid-state Nuclear Magnetic Resonance Spectroscopy
Published on: September 17, 2017
(17)O multiple-quantum MAS NMR study of high-pressure hydrous magnesium silicates
S E Ashbrook1, A J Berry, S Wimperis
1School of Chemistry, University of Exeter, Stocker Road, Exeter EX4 4QD, United Kingdom.
Journal of the American Chemical Society
|June 28, 2001
Summary
This study synthesized hydroxyl-chondrodite and hydroxyl-clinohumite using enriched oxygen-17. Advanced NMR techniques successfully assigned all oxygen sites in these minerals, revealing a correlation with silicon-oxygen bond lengths.
Area of Science:
- Solid-state chemistry
- Mineral physics
- Nuclear Magnetic Resonance (NMR) spectroscopy
Background:
- Hydrous magnesium silicates like hydroxyl-chondrodite and hydroxyl-clinohumite are important rock-forming minerals.
- Understanding their structure at the atomic level is crucial for geochemistry and materials science.
- Previous studies have lacked detailed characterization of oxygen sites in these specific minerals.
Purpose of the Study:
- To synthesize oxygen-17 (17O)-enriched hydroxyl-chondrodite and hydroxyl-clinohumite.
- To characterize the distinct oxygen sites within these minerals using high-field multiple-quantum (MQ) MAS NMR.
- To assign these oxygen sites and investigate their relationship with mineral structure.
Main Methods:
- Synthesis of (17)O-enriched hydroxyl-chondrodite and hydroxyl-clinohumite.
- High-resolution (17)O multiple-quantum (MQ) MAS NMR spectroscopy at 9.4 and 16.4 T.
- (17)O [(1)H] cross-polarization and comparison with (17)O-enriched brucite for hydroxyl site assignment.
- Analysis of isotropic chemical shifts and quadrupolar parameters.
Main Results:
- Successful synthesis of (17)O-enriched hydroxyl-chondrodite and hydroxyl-clinohumite.
- Acquisition and analysis of high-field (17)O MQ MAS NMR spectra, resolving distinct oxygen sites.
- Complete assignments proposed for five oxygen sites in hydroxyl-chondrodite and nine in hydroxyl-clinohumite.
- Observed correlation between (17)O isotropic chemical shift and Si-O bond length, supporting assignments.
Conclusions:
- The study provides a comprehensive assignment of oxygen sites in hydroxyl-chondrodite and hydroxyl-clinohumite using advanced NMR techniques.
- The findings enhance the understanding of structure-property relationships in hydrous magnesium silicates.
- The correlation between NMR parameters and bond lengths validates the proposed site assignments and offers a predictive tool.
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