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Characterization of Hydrous Species in Minerals by High-speed ^1H MAS-NMR

Yesinowski, James P. and Eckert, Hellmut and Rossman, George R. (1988) Characterization of Hydrous Species in Minerals by High-speed ^1H MAS-NMR. Journal of the American Chemical Society, 110 (5). pp. 1367-1375. ISSN 0002-7863. https://resolver.caltech.edu/CaltechAUTHORS:20130801-084732362

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Abstract

Proton magic-angle spinning (MAS) NMR at 200 and 500 MHz and at high spinning speeds (ca. 8 kHz) has been used to characterize hydrous species, both stoichiometric and nonstoichiometric, in a variety of minerals. High-resolution ^1H MAS-NMR spectra of minerals containing stoichiometric hydroxyl groups as the only hydrous species are obtainable provided that the hydrogen density in the sample is less than about 15 atoms/nm^3. Structurally isolated water molecules in analcite, NaAlSi_2O_6•H_2O, and gypsum, CaSO_4•2H_2O, yield characteristic ^1H MAS-NMR spectra with numerous spinning sidebands extending over a range of about 100 kHz, reflecting the strong, largely inhomogeneous character of the homonuclear dipolar coupling. The field dependence of both line widths and spinning sideband patterns provides evidence about the nature of the broadening interactions. Lawsonite and hemimorphite, minerals containing stoichiometric amounts of both OH and H_2O groups, yield spectra with numerous intense spinning sidebands; strong dipolar interactions preclude discrimination of OH and H_2O. Nonstoichiometric hydrogen in nominally anhydrous minerals (feldspars, nepheline, quartz, and grossular garnet) is found to occur in a variety of forms: mobile H_2O in fluid inclusions, anisotropically constrained, isolated H_2O molecules, and clustered species consistent with H_4O_4^(4-) groups in a hydrogarnet substitution.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1021/ja00213a007DOIArticle
http://pubs.acs.org/doi/abs/10.1021/ja00213a007PublisherArticle
Alternate Title:Characterization of hydrous species in minerals by high-speed proton MAS-NMR
Additional Information:© 1988 American Chemical Society. Received August 19, 1987. The NMR studies were conducted at the Southern California Regional NMR Facility, supported by NSF Grant 84-40137. We are also grateful to Chevron Oil Field Research Corp. for their financial support for a MAS-NMR probe. One of us (G.R.R.) acknowledges support by NSF grants EAR 86-18200 and EAR 83-13098.
Funders:
Funding AgencyGrant Number
NSF84-40137
Chevron Oil Field Research Corp.UNSPECIFIED
NSFEAR 86-18200
NSFEAR 83-13098
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Other Numbering System NameOther Numbering System ID
Caltech Division of Geological and Planetary Sciences4497
Issue or Number:5
Record Number:CaltechAUTHORS:20130801-084732362
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20130801-084732362
Official Citation: Characterization of hydrous species in minerals by high-speed proton MAS-NMR James P. Yesinowski, Hellmut. Eckert, and George R. Rossman Journal of the American Chemical Society 1988 110 (5), 1367-1375
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:39696
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:01 Aug 2013 17:24
Last Modified:03 Oct 2019 05:09

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