High-resolution oxygen-17 NMR spectroscopy of solids by multiple-quantum magic-angle-spinning

High-resolution solid state O-17 NMR spectra of O-17-enriched compounds were observed with multiple-quantum magic-angle-spinning (MQMAS) experiments. The resolution of the O-17 MQMAS spectra is approximately 30- to 150-fold higher than that found in conventional O-17 MAS spectra, making it possible to detect crystallographically distinct oxygen sites. It is shown that O-17 MQMAS studies are feasible for systems with O-17 quadrupole coupling constants up to 7 MHz, provided that sufficiently high radio-frequency field strengths (> 120 kHz) and spinning speeds (similar to 20 kHz) can be achieved. (C) 1997 Published by Elsevier Science B.V.