(Na₄BH₄)³⁺ guests inside aluminosilicate, gallosilicate and aluminogermanate sodalite host frameworks studied by ¹H, ¹¹B, and ²³Na MAS NMR spectroscopy

authored by

J. Ch Buhl, M. M. Murshed

Abstract

We report tetrahydroborate aluminosilicate, gallosilicate and aluminogermanate sodalites studied by ¹¹B, ¹H and ²³Na MAS NMR spectroscopy. The spectral parameters are consistent with the local environments of each investigated nucleus obtained from the crystal structures. The ¹¹B MAS NMR spectra exhibit a sharp narrow line at about -49.0 ppm, which is assigned to BH₄^- enclathrated into the sodalite framework matrix. The lineshape of the signal shows no quadrupolar interactions due to discreteness and high symmetry of the BH₄^- unit as well as possible fast dynamic site exchange of hydrogen atoms. The ²³Na 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 ¹H MAS NMR spectra can clearly distinguish between hydrogen in BH₄^- anions (-0.6 ppm), H₃O₂^- anions (1.2 ppm) and H₂O molecules (5.0 ppm). The structural properties of BH₄^- intercalation into sodalite framework matrix help connect the microporous materials to hydride-containing A, X and Y type zeolites.

Organisation(s)

Institute of Mineralogy

External Organisation(s)

University of Göttingen

Type

Article

Journal

Materials research bulletin

Volume

44

Pages

1581-1585

No. of pages

5

ISSN

0025-5408

Publication date

01.07.2009

Publication status

Published

Peer reviewed

Yes

ASJC Scopus subject areas

General Materials Science, Condensed Matter Physics, Mechanics of Materials, Mechanical Engineering

Electronic version(s)

https://doi.org/10.1016/j.materresbull.2009.01.023 (Access: Closed)