From crystalline to glassy gallium fluoride materials: an NMR study of Ga-69 and Ga-71 quadrupolar nuclei (vol 14, pg 181, 1999)

Owing to the implementation of acquisition techniques specific for nuclei w ith very large quadrupolar interaction (full shifted echo and variable offs et cumulative spectra (VOCS)), MMR spectra of Ga-69 and Ga-71 are obtained in crystallised (PbGaF5, Pb3Ga2F12, Pb9Ga2F24 and CsZnGaF6) and glassy (PbF 2-ZnF2-GaF3) gallium fluorides. Simulations of both static (full echo or VO CS) and 15 kHz MAS spectra allow to obtain consistent determinations of iso tropic chemical shifts and very large quadrupolar parameters (v(Q) up to 14 MHz). Ln the crystalline compounds whose structures are unknown, the numbe r and the local symmetry of the different gallium sites are tentatively wor ked out. For the glassy systems, a continuous Czjzek's distribution of the NMR quadrupolar parameters accounts for the particular shape of the NMR spe ctrum. (C) 1999 Elsevier Science B.V. All rights reserved.