Nuclear magnetic resonance (NMR) spectra of93Nb,45Sc, and207Pb, as well as dielectric permittivity temperature dependence in a wide frequency range, were investigated in the solid solution of ferroelectric relaxors(x)PbMg1/3Nb2/3O3—(1−x)PbSc1/2Nb1/2O3(0⩽x⩽1). The peculiar behavior of the observed quantities and parameters, e.g., disappearance of dielectric dispersion forx∼0.5, is revealed. The analysis of the dependence of45ScNMR spectra onxhas shown that ordering of the regions containing Sc ions takes place forx>0.45. The investigation of the temperature dependence of93Nband45ScNMR linewidths inPbSc1/2Nb1/2O3had shown that atT<TmaxNb and Sc ions are shifted from their equilibrium lattice sites (Tmaxcorresponds to dielectric permittivity maximum). Latter shifts contribute to the temperature dependence of lattice polarizationP, whereas the jump ofPatT=Tmaxis determined by shifts of Pb ions. The peculiarities of NMR line shape in the investigated materials gave evidence of randomness in the directions and values of Nb, Sc, and Pb dipole moments. ©1997 American Institute of Physics.