When Rb+ is incorporated into different cubic halide lattices at very low concentrations, the Rb-87 NMR chemical shift becomes more shielded by as much as 282 ppm when the cation is changed from Na+ to Cs+. Similarly, in mixed crystals of KCl and RbCl, the average resonance frequency shifts with the degree of incorporation. The Rb-87 chemical shift data for each halide show a near-linear correlation with the average alkali metal-halide interionic distance in the different crystals studied, in good agreement with ab initio calculations which show that indeed the chemical shielding has a strong dependence on the nearest neighbor shell. of halide anions and their distance from the Rb+. When the Rb concentration is increased as in KCl/ RbCl solid solutions, the Rb-87 NMR spectra are influenced by a large distribution of K/Rb configurations in the next-nearest-neighbor shell of 12 cations. While the total shift is still largely dependent on the Rb-Cl distance, shells containing both K and Rb atoms give rise to second-order quadrupolar effects and an offset from the isotropic chemical shift. This wort; is a remarkable demonstration of the sensitivity of the Rb-87 nucleus to its physical environment.