QUADRUPOLE COUPLING AND ANISOTROPIC SHIELDING FROM SINGLE-CRYSTAL NMROF THE CENTRAL TRANSITION FOR QUADRUPOLAR NUCLEI - RB-87 NMR OF RBCLO4 AND RB2SO4

The possibility of retrieving parameters for the combined effect of qu adrupole coupling and small chemical-shielding anisotropies from singl e-crystal NMR of the central transition for half-integer quadrupolar n uclei has been successfully investigated, Rb-87 single-crystal NMR of RbClO4 and Rb2SO4 serve as two properly chosen and illustrative exampl es, Thereby, discrepancies between some of the Rb-87 parameters recent ly reported for these two interactions in powders of RbClO4 and Rb2SO4 , and determined from MAS and static powder NMR, have been clarified, The orientations of the crystallographic axes for the two rubidium cry stals have been predicted by the NMR results and verified independentl y by XRD analysis. (C) 1996 Academic Press, Inc.