Calculation of 17 O NMR shieldings in molecular models for crystalline MO, M=Mg, Ca, Sr, and in models for alkaline earth silicates

Abstract

17O NMR shieldings are calculated for the central O in the molecular model OM6(OH)12 −2, for crystalline alkaline earth oxides, MO, where M=Mg, Ca, and Sr, using both Hartree–Fock and hybrid Hartree–Fock density-functional theory. Agreement of calculated and experimental NMR shifts of CaO and SrO compared to MgO is good, but only if the basis set on the M atoms has sufficient tight d polarization functions. Preliminary results are also presented for nonbridging O in the silicate Si(OH)3O− anion, perturbed by alkaline earth cations, giving trends which agree qualitatively with experiment.