Lead-207 NMR Spectroscopic Study of Lead-Based Electronic Materials and Related Lead Oxides

Static and MAS 207Pb NMR spectra of a series of lead oxides, including the electronic materials PbTiO3 (PT), PbZrO3, Pb(Zr0.53Ti0.47)O3, Pb(Mg0.33Nb0.67)O3 (PMN), and 0.66PMN/0.34PT, have been measured. The chemical shift parameters (δiso, δaniso, and η) and the spin−lattice relaxation times have been determined for most of these compounds. The symmetry of the local environment of the lead(II) site and the covalency of the Pb−O bonds are determined to be the best indicators of the 207Pb chemical shift parameters. Ionic compounds (e.g., PbSO4 and Pb(NO3)2) have isotropic chemical shifts from −3600 to −2500 ppm and small absolute anisotropic chemical shifts (\u3c500 \u3eppm); while covalent lead oxides (e.g., PbO and Pb3O4) have isotropic chemical shifts from 800 to 1900 ppm and large absolute anisotropic chemical shifts (1900 to 2600 ppm). PbTiO3 and PbZrO3 have intermediate isotropic (−1419 to −1017 ppm) and anisotropic chemical shifts (−838 to −546 ppm) consistent with an intermediate degree of covalent bonding. Pb(Zr0.53Ti0.47)O3, PMN, and 0.66PMN/0.34PT have single broad asymmetric 207Pb NMR resonances, with chemical shifts and line widths consistent with Pb−O bonds that are less covalent than those in PbO and more covalent than those in PbTiO3 and PbZrO3. For the 207Pb NMR spectra of Pb(Zr0.53Ti0.47)O3, PMN, and 0.66PMN/0.34PT, chemical shift dispersion is a significant contribution to the line width, consistent with the presence of a range of inequivalent lead(II) sites in these disordered perovskite materials