V-51 NMR-STUDIES OF CRYSTALLINE MONOVALENT AND DIVALENT METAL METAVANADATES

V-51 static and magic-angle spinning (MAS) NMR spectra Of crystalline monovalent metal metavanadates LiVO3, alpha- and beta-NaVO3, KVO3, CsVO3, beta-AgVO3, and NH4VO3 and divalent metal metavanadates M(VO3)2 (M = Mg, Ca, Sr, Ba, Zn, Pb) have been measured in order to establish the relationships between the various NMR parameters, such as isotropic chemical shift, delta(iso), chemical shift anisotropy, \DELTAdelta\, the asymmetry parameter, eta, and the crystallographic parameters. When the structural units are the same, in this case VO4 tetrahedra or VO5 trigonal bipyramids, the delta(iso) decrease almost linearly with decreasing average V-0 bond length, independent of the polymerization degree and linkage mode of the VO(n), polyhedra. \DELTAdelta\ increases with the polymerization degree and the degree of the structural distortion of the VO(n) polyhedron. It is found possible to predict the structural unit and the polymerization degree on the basis of the relation between \DELTAdelta\ and eta. (C) 1994 Academic Press, Inc.