Researchers measured 93Nb solid-state NMR spectra of various niobates, identifying the chemical shielding and quadrupole tensor parameters using advanced NMR techniques.
The study established a new 93Nb NMR chemical shift scale linked to the coordination number of Nb, with specific ppm ranges for four, five, six, seven, and eight-coordinated Nb sites.
Additionally, a correlation was suggested between the isotropic chemical shift and the ionic character of NbOx-MOy associations, with the quadrupole coupling constant varying significantly based on the local symmetry of Nb sites.