Study of the Aluminophosphates Alpo4-21 and Alpo4-25 by Al-27 Double-Rotation Nmr

TitleStudy of the Aluminophosphates Alpo4-21 and Alpo4-25 by Al-27 Double-Rotation Nmr
Publication TypeJournal Article
Year of Publication1991
AuthorsJelinek R., Chmelka B.F, Wu Y., Grandinetti P.J, Pines A, Barrie P.J, Klinowski J.
JournalJournal of the American Chemical Society
Volume113
Issue11
Pagination4097-4101
Date PublishedMay 22
ISBN Number0002-7863
Accession NumberWOS:A1991FN00500007
Keywordsnuclei
Abstract

Aluminum-27 double-rotation NMR in a magnetic field of 11.7 T distinguishes the extremely distorted five-coordinated aluminum sites in the molecular sieve precursor ALPO4(-21). Upon calcination, ALPO4(-21) transforms to ALPO4(-25), which has two tetrahedral aluminum sites with similar isotropic chemical shifts that cannot be resolved in an 11.7 T field. The two tetrahedral environments, however, have a different quadrupole coupling constants and are distinguished by double rotation at 4.2 T field. The quadrupole coupling constants obtained for these sites indicates that the tetrahedral aluminum environments are less distorted in the hydrated material.

URL<Go to ISI>://WOS:A1991FN00500007
DOI10.1021/Ja00011a007
Short TitleStudy of the Aluminophosphates Alpo4-21 and Alpo4-25 by Al-27 Double-Rotation Nmr
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