Pb-207 NMR, powder diffraction, and Monte Carlo studies of PbxM1-x(NO3)(2)solid solutions

The solid solutions [Pb,Sr](NO3)(2) and [Pb,Ba](NO3)(2) show a multiplicity of Pb-207 NMR signals, arising from shifts of the Pb-207 resonances by les s polarizable neighbors. The shifts have a unique anisotropic signature tha t allows tentative assignment of some of the signals. Monte Carlo simulatio n of the spectral intensities shows that the ions are slightly clustered in the crystal, which disagrees with:a conventional but specious analysis of the dependence of the unit cell volume on composition. The extent of the cl ustering is attributable to the differences between the van der Waals inter action energies of the ions.