Solid-State Gallium-69 and Gallium-71 Nuclear Magnetic Resonance Spectroscopic Studies of Gallium Analogue Zeolites and Related Systems

We have obtained solid-state 11,7-T⁶⁹Ga and⁷¹Ga nuclear magnetic resonance (NMR) spectra of a series of gallosilicates (gallium analogues of zeolites Na-X, Na-Y, Na-sodalite, and Na-natrolite). From the apparent⁶⁹Ga and⁷¹Ga chemical shifts, values of the nuclear quadrupole coupling constants (e¹qQ/h) and the true, isotropic chemical shifts (5;) have been deduced for the framework, tetrahedral, Ga(OSi)₄sites. The e^{23 4 56}qQ/h values are in the range 1.9-2.7 MHz for⁶⁹Ga and 1.2-1.7 MHz for⁷¹Ga. The isotropic chemical shifts are all in the range 171–186 ppm downfield from an external standard of 1 M Ga(N0₃)₃. Our results indicate that measurement of the apparent (second-order shifted) chemical shifts for pairs of isotopes of nonintegral spin quadrupolar nuclei in solids at one magnetic field strength is a useful new approach for determination of both isotropic chemical shifts and nuclear quadrupole coupling constant values.