Solid-state sup 23 Na and sup 27 Al MAS NMR study of the dehydration of Na sub 2 Oter dot Al sub 2 O sub 3 ter dot 3H sub 2 O

The dehydration of Na{sub 2}O{center dot}Al{sub 2}O{sub 3}{center dot}3H{sub 2}O was investigated as a function of dehydration temperature (100-600C) and dehydration time, using solid-state {sup 23}Na and {sup 27}Al nuclear magnetic resonance with high-speed magic-angle spinning (MAS). {sup 23}Na an...

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Bibliographic Details
Published in:Journal of the American Chemical Society 1990-12, Vol.112:25
Main Authors: Dec, S.F., Maciel, G.E., Fitzgerald, J.J.
Format: Article
Language:English
Subjects:
360202 - Ceramics, Cermets, & Refractories- Structure & Phase Studies
400201 - Chemical & Physicochemical Properties
ALKALI METAL COMPOUNDS
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
ANISOTROPY
CHALCOGENIDES
CHEMICAL SHIFT
DEHYDRATION
HAMILTONIANS
HYDRATES
INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY
KINETICS
MAGNETIC RESONANCE
MATERIALS SCIENCE
MATHEMATICAL OPERATORS
MOLECULAR STRUCTURE
NUCLEAR MAGNETIC RESONANCE
OXIDES
OXYGEN COMPOUNDS
QUANTUM OPERATORS
REACTION KINETICS
RESONANCE
SODIUM COMPOUNDS
SODIUM OXIDES
TEMPERATURE RANGE
TEMPERATURE RANGE 0400-1000 K
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Summary:The dehydration of Na{sub 2}O{center dot}Al{sub 2}O{sub 3}{center dot}3H{sub 2}O was investigated as a function of dehydration temperature (100-600C) and dehydration time, using solid-state {sup 23}Na and {sup 27}Al nuclear magnetic resonance with high-speed magic-angle spinning (MAS). {sup 23}Na and {sup 27}Al MAS NMR spectra were recorded at field strengths of 8.4, 11.7, and 14.0 T. The field dependence of the NMR measurements aid in determining the presence of a number of chemically distinct sodium and aluminum sites. The MAS NMR results indicate that both untreated and dehydrated Na{sub 2}O{center dot}Al{sub 2}O{sub 3}3H{sub 2}O contain three chemically distinct sodium sites and one aluminum site. Simulation of the observed {sup 23}Na and {sup 27}Al spectra yields quadrupole coupling constants and asymmetry parameters for each sodium and aluminum site which, when used in combination with isotropic chemical shift measurements, permit various structures to be assigned to the sodium and aluminum sites. Water weight-loss measurements indicate that all structural changes observed in both the {sup 23}Na and {sup 27}Al NMR spectra are related to the progress of dehydration, although not all the water is removed, even after heating at 598C for extended times.
ISSN:0002-7863
1520-5126
DOI:10.1021/ja00181a006