Solid-State 87Sr NMR Spectroscopy at Natural Abundance and High Magnetic Field Strength

Twenty-five strontium-containing solids were characterized via 87Sr NMR spectroscopy at natural abundance and high magnetic field strength (B0 = 21.14 T). Strontium nuclear quadrupole coupling constants in these compounds are sensitive to the strontium site symmetry and range from 0 to 50.5 MHz. An experimental 87Sr chemical shift scale is proposed, and available data indicate a chemical shift range of approximately 550 ppm, from −200 to +350 ppm relative to Sr2+(aq). In general, magnetic shielding increased with strontium coordination number. Experimentally measured chemical shift anisotropy is reported for stationary samples of solid powdered SrCl2·6H2O, SrBr2·6H2O, and SrCO3, with δaniso(87Sr) values of +28, +26, and −65 ppm, respectively. NMR parameters were calculated using CASTEP, a gauge including projector augmented wave (GIPAW) DFT-based program, which addresses the periodic nature of solids using plane-wave basis sets. Calculated NMR parameters are in good agreement with those measured.