29Si and 17O (Q)CPMG-MAS solid-state NMR experiments as an optimum approach for half-integer nuclei having long T1 relaxation times

A significantly reduced experiment time for half-integer nuclei with long T1 relaxation times has been demonstrated by 29Si CPMG-MAS or 17O QCPMG-MAS experiments on α-cristobalite, a radiation damaged Zircon and 17O enriched α-quartz, respectively. For 29Si up to 37 h were saved compared to the MAS experiment using longer recycle periods (up to 3600 s) but fewer scans. The spectrum reconstructed from the echoes provides similar spectral information as the MAS spectrum. In the 17O spectrum increased sensitivity facilitated determination of CSA in α-quartz at 9.4 T and points towards a method to obtain natural abundance 17O spectra of non-cubic oxides.