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

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