Preparation of needle-like NaNbO3 by molten NaOH method

摘要

Needle-like NaNbO₃ has been prepared in two steps by a molten NaOH method. First, Na₇(H₃O)Nb₆O₁₉·14H₂O precursor was synthesized by the reaction of Nb₂O₅ with a molten NaOH at 450°C for 50 h in air. The Na₇(H₃O)Nb₆O₁₉·14H₂O precursor was a needle-like single crystal 0.25–1.5 μm wide and >3 μm long. Then, the Na₇(H₃O)Nb₆O₁₉·14H₂O precursor crystal transformed to NaNbO₃ through an intermediate Na₇(H₃O)Nb₆O₁₉ by a heating above 500°C. The NaNbO₃ was a needle-like polycrystal with a perovskite-type structure.