17O multiple-quantum MAS NMR study of pyroxenes

Ashbrook, S.E., Berry, A.J. and Wimperis, S. (2002) 17O multiple-quantum MAS NMR study of pyroxenes. Journal of Physical Chemistry B, 106(4), pp. 773-778. (doi: 10.1021/jp0130362)

Abstract

Two-dimensional triple-quantum 17O (I = 5/2) MAS NMR powder spectra were obtained for orthoenstatite, clinoenstatite, and protoenstatite (MgSiO3 polymorphs) and diopside (CaMgSi2O6). The spectra were analyzed to yield the 17O isotropic chemical shifts (δCS) and quadrupolar coupling parameters (PQ = CQ(1 + η2/3)1/2) of the oxygen sites in each sample. High-resolution isotropic projections exhibit resolved 17O peaks equal in number to the number of crystallographically inequivalent oxygen sites. Bridging and nonbridging oxygens were distinguished by their characteristic PQ values. Further assignments were possible by comparing the isotropic 17O NMR spectra for this series of similar compounds with that reported previously for forsterite (Mg2SiO4). Full assignments of the three oxygen sites in protoenstatite and diopside and of the six sites in orthoenstatite and clinoenstatite are suggested.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Wimperis, Professor Stephen
• Authors: Ashbrook, S.E., Berry, A.J., and Wimperis, S.
• Subjects: Q Science > QD Chemistry
• College/School: College of Science and Engineering > School of Chemistry
• Journal Name: Journal of Physical Chemistry B
• ISSN: 1520-6106
• Published Online: 03 January 2002