Journal of Physical Chemistry B, Vol.101, No.19, 3727-3733, 1997
Cesium-133 NMR-Study of Cscd(SCN)(3) - Relative Orientation of the Chemical-Shift and Electric-Field Gradient Tensors
Single-crystal NMR was used to characterize the cesium-133 chemical shift and electric field gradient (EFG) tensors in CsCd(SCN)(3). The principal axes of the two interaction tensors are not coincident, a reflection of the general positioning of cesium nuclei within the unit cell. Relative orientations of the chemical shift and EFG tensors have been determined, but assignment of the two magnetically distinct sites remains elusive. The span of the chemical shift, 94.4 ppm, is moderate in comparison with other cesium salts, and the magnitude of the nuclear quadrupole coupling constant, 148 kHz, is in the midrange of those reported for cesium compounds. Excellent agreement is observed between experimental Cs-133 NMR spectra of a stationary powder sample and spectra calculated using NMR parameters from the single-crystal analysis. Moreover, simulations indicate that the static line shape is very sensitive to the relative orientation of the chemical shift and EFG tensors. Experimental Cs-133 NMR spectra obtained with magic-angle and variable-angle spinning are well reproduced by calculations utilizing single-crystal NMR data.
Keywords:NUCLEAR-MAGNETIC-RESONANCE;SOLID-STATE NMR;ANISOTROPIC SHIELDING TENSORS;PRINCIPAL-AXIS SYSTEMS;RB-87 MAS NMR;QUADRUPOLAR NUCLEI;V-51 QUADRUPOLE;LINE-SHAPES;CO-59 NMR;CS-133