The feasibility of Ru-99 NMR spectroscopy as a tool to characterize solid compounds is demonstrated. Results of the first solid-state Ru-99 NMR investigation of diamagnetic compounds are presented for Ru(NH3)(6)Cl-2, K4Ru(CN)(6) (.) XH2O (X = 0, 3), LaKRu(CN)(6), and Ru-3(CO)(12). The sensitivity of the ruthenium magnetic shielding tensor to subtle changes in the local structure about the ruthenium nucleus is highlighted by comparing the Ru-99 isotropic chemical shift of Ru(NH3)(6)Cl-2 in aqueous solutions and in the solid state. The narrow isotropic Ru-99 NMR peak observed for solid Ru(NH3)(6)Cl-2 indicates that this compound is an ideal secondary reference sample for solid-state 99Ru NMR studies. The isotropic Ru-99 chemical shift, Ru-99 nuclear quadrupolar coupling constant, C-Q, and quadrupolar asymmetry parameter of K4Ru(CN)(6) . xH(2)O (x = 0, 3) are shown to be sensitive to x. For Ru-3(CO)(12), the magnetic shielding tensors of each of the three nonequivalent Ru nuclei have spans of 1300-1400 ppm, and the Ru-99 C-Q values are also similar, 1.36-1.85 MHz, and are surprisingly small given that 99Ru has a moderate nuclear quadrupole moment. Information about the relative orientation of the Ru magnetic shielding and electric field gradient tensors has been determined for Ru-3(CO)(12) from experimental Ru-99 NMR spectra as well as quantum chemical calculations.