Аннотация:Single phase ceramic samples of new compositions (1 − x)NaNbO3 – хLiNbO3 (x = 0; 0.05; 0.10; 0.15), modified with a LiF additive, are prepared through solid state reactions, and their crystal structure, microstructure and dielectric and nonlinear optical properties are studied. A drop from 108.1 to 42.8 nm of the volume-weighted crystallite size distribution function corresponding to coherent scattering regions is observed. A rise in the temperature of phase transitions and a weakening of nonlinear optical properties are revealed as the concentration of Li cations grows.