Ga-71 NMR of reference Ga-IV, Ga-V, and Ga-VI compounds by MAS and QPASS, extension of gallium/aluminum NMR parameter correlation

We report new measurements of NMR parameters for Ga-71 in gallium bearing o xide reference compounds, ranging from perfectly ordered systems to disorde red crystalline structures and their aluminate counterparts, Static, MAS, a nd QPASS spectra are obtained at magnetic fields ranging from 7.0 to 18.8 T , With these results we enhance the previously established correlation betw een isotropic chemical shifts of Ga-71 and Al-27 and propose a correlation between gallium and aluminum electric field gradients (EFG), This correlati on shows that the EFG at 71Ga sites are generally three times greater than those at equivalent Al-27 sites. (C) 1999 Elsevier Science B.V. All rights reserved.