(Na{sub 4}BH{sub 4}){sup 3+} guests inside aluminosilicate, gallosilicate and aluminogermanate sodalite host frameworks studied by {sup 1}H, {sup 11}B, and {sup 23}Na MAS NMR spectroscopy
- Institut fuer Mineralogie, Universitaet Hannover, Callinstrasse 3, 30167 Hannover (Germany)
We report tetrahydroborate aluminosilicate, gallosilicate and aluminogermanate sodalites studied by {sup 11}B, {sup 1}H and {sup 23}Na MAS NMR spectroscopy. The spectral parameters are consistent with the local environments of each investigated nucleus obtained from the crystal structures. The {sup 11}B MAS NMR spectra exhibit a sharp narrow line at about -49.0 ppm, which is assigned to BH{sub 4}{sup -} enclathrated into the sodalite framework matrix. The lineshape of the signal shows no quadrupolar interactions due to discreteness and high symmetry of the BH{sub 4}{sup -} unit as well as possible fast dynamic site exchange of hydrogen atoms. The {sup 23}Na MAS NMR signals also show a narrow Gaussian lineshape, which clearly indicates a single type of sodium coordination, and a centrosymmetrical charge distribution around the sodium atom. The {sup 1}H MAS NMR spectra can clearly distinguish between hydrogen in BH{sub 4}{sup -} anions (-0.6 ppm), H{sub 3}O{sub 2}{sup -} anions (1.2 ppm) and H{sub 2}O molecules (5.0 ppm). The structural properties of BH{sub 4}{sup -} intercalation into sodalite framework matrix help connect the microporous materials to hydride-containing A, X and Y type zeolites.
- OSTI ID:
- 22029812
- Journal Information:
- Materials Research Bulletin, Vol. 44, Issue 7; Other Information: Copyright (c) 2009 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0025-5408
- Country of Publication:
- United States
- Language:
- English
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