Calcium rubidium nitrate, 2Ca(NO3)(2)-3RbNO(3) (CRN),has been studied in its molten and glassy states using Rb-87 NMR techniques. In the solid phase asymmetric and smeared quadrupole perturbed spectra of the central Rb resonance reflect a highly disordered ionic local structure. At low temperatures, T < 80 K, the spin-lattice relaxation times follow a power law, T-1 proportional to T-alpha with alpha = 3. A local T-1 minimum near T = 145 K reveals the slow down of the 3-fold rotation of the planar nitrate group. The NMR results are compared with the conductivity relaxation in CRN.