MAGNITUDES AND RELATIVE ORIENTATION OF V-51 QUADRUPOLE COUPLING AND ANISOTROPIC SHIELDING TENSORS IN METAVANADATES AND KV3O8 FROM V-51 MAS NMR-SPECTRA - NA-23 QUADRUPOLE COUPLING PARAMETERS FOR ALPHA-NAVO3 AND BETA-NAVO3

V-51 MAS NMR spectra, exhibiting the complete manifold of spinning sidebands (ssb's) from all seven V-51 (I = 7/2) single-quantum transitions, have been obtained for a series of metavanadates (MVO3, M = Li, Na, K, NH4, Tl) and for KV3O8 employing spectral windows up to 2 MHz. These MAS NMR spectra are influenced by interactions from both the V-51 quadrupole coupling and chemical shielding anisotropy. Analysis of the spectra has been performed in terms of the two interactions employing a newly developed method requiring simulations and iterative fitting of the calculated to the experimental intensities of the spinning sidebands. Accurate values for all eight parameters describing the magnitude and relative orientation of the quadrupole coupling and anisotropic shielding tensors are obtained. The applicability and high performance of the method are illustrated by comparison of simulated and experimental MAS spectra, but also when V-51 parameters are compared to literature data determined for a few of the vanadates from static NMR and nuclear quadrupole resonance. Correlations between V-51 parameters and structural characteristics for the metavanadates are discussed. Furthermore, the two polymorphs alpha- and beta-NaVO3 along with a commercial sample of sodium metavanadate (consisting of a mixture of these polymorphs) are characterized by Na-23 MAS NMR and the Na-23 quadrupole coupling parameters and isotropic chemical shifts determined from these spectra.