This study investigates the phase formation of Zr-substituted [(Na0.5Bi0.5)(0.80)Ba-0.20](Ti1-yZry)O-3 system during its solid-state synthesis. The synthesis was found to be a multistep process accompanied by the formation of a number of intermediate phases which depend on the solid solution's composition and sintering temperatures. Single-phase solid solutions were obtained when the sintering temperature was increased to 1000 degrees C-1100 degrees C. Increase in content of substituting Zr-ions tends to linearly increase in the size of the crystal cell leading to reduction in the tolerance factor which results in the increase in stability of the antiferroelectric phase relative to the ferroelectric phase.