Strontium and calcium pyroniobates were prepared by a sol–gel process, using strontium/calcium metal and niobium ethoxide as precursors. The formation of Sr2Nb2O7occurred at 750°C via an intermediate perovskite phase of composition close to Sr0.82NbO3. The crystallization of Ca2Nb2O7occurred at 600°C directly without any intermediate phases. Sintered Sr2Nb2O7and Ca2Nb2O7pellets showed a preferred grain orientation. Microstructural studies revealed an increase in grain growth and associated orientation with sintering temperat