Niobium-93 MQMAS NMR Spectroscopic Study of Alkali and Lead Niobates

93Nb (I=9/2) multiple-quantum magic-angle spinning (MQMAS) NMR spectra of a series of inorganic niobates have been measured. 93Nb MQMAS spectroscopy yields spectra with typically an order of magnitude higher resolution than that obtainable with 93Nb MAS spectroscopy and 93Nb dynamic-angle spinning (...

Full description

Saved in:
Bibliographic Details
Published in:Solid state nuclear magnetic resonance 2001-02, Vol.19 (1-2), p.45-62
Main Authors: Prasad, S., Zhao, P., Huang, J., Fitzgerald, J.J., Shore, J.S.
Format: Article
Language:English
Subjects:
DAS
Magnetic Resonance Spectroscopy
MQMAS
niobate
niobium
Niobium - chemistry
nutation
Oxides
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:93Nb (I=9/2) multiple-quantum magic-angle spinning (MQMAS) NMR spectra of a series of inorganic niobates have been measured. 93Nb MQMAS spectroscopy yields spectra with typically an order of magnitude higher resolution than that obtainable with 93Nb MAS spectroscopy and 93Nb dynamic-angle spinning (DAS) spectroscopy. For example, the full-width at half-maximums of the 93Nb resonances of LiNbO3 were 9 (MAS), 5.8 (DAS), and 0.7 kHz (MQMAS). Broadening of the 93Nb MAS and DAS spectra is due to the second-order quadrupolar and homonuclear dipolar interactions, respectively. The quadrupolar products (PQ) and isotropic chemical shifts (δiso) of the 93Nb resonances of LiNbO3, NaNbO3, PbNb2O6, Pb2Nb2O7, Pb3Nb2O8, Pb5Nb4O15, Pb3Nb4O13, and Pb1.83Nb1.71Mg0.29O6.39 were determined from MQMAS spectra and range from 13.6 to 26.8 MHz and from −951 to −1113 ppm, respectively. Resonances with relatively large quadrupolar coupling constants (>30 MHz) were not observed using MQMAS spectroscopy, but were detected using nutation spectroscopy. The applicability and limitations of MQMAS spectroscopy in studying inorganic niobates containing multiple 93Nb resonances are addressed and compared with those of MAS, nutation, and DAS spectroscopies.
ISSN:0926-2040
1527-3326
DOI:10.1006/snmr.2000.0022