Improved resolution and detection of 31P-Tl J-couplings at 21Â T in 31P magic angle spinning NMR spectra of inorganic compounds containing Tl/Bi/P/S

For crystalline compounds containing Tl, Bi, P, and S, greatly improved chemical shift resolution was observed in 31P magic angle spinning spectra obtained at 21 T relative to spectra obtained at 9.4 T. In Hz units, the spectral linewidths were not strongly dependent on the applied field, which may be a result of a significant contribution to the linewidths from transverse relaxation. Comparison of the spectra at the two different fields confirmed that spectral splittings were due to two-bond phosphorus-thallium J-coupling. These results suggest that ultra-high field may be a useful tool to improve spectral resolution of spin 12 nuclei in crystalline inorganic compounds.