Density functional theory calculations of 11B NMR parameters in crystalline borates

The 11B nuclear magnetic resonance (NMR) shielding and electric field gradient parameters for several borate crystal structures have been calculated using density functional theory and the gauge-including projector augmented wave method with plane-wave basis sets and pseudopotential approximation. The results show good agreement with the existing experimental data. Significantly large variation in the 11B NMR isotropic chemical shift is observed for BO3 sites with all three bridging oxygen atoms in triborate and boroxol rings and non-ring geometries. Such variations could be attributed to the corresponding differences in the B–O–B angles. The nature of the boroxol rings in glassy B2O3 is discussed in light of these data.