Low-temperature synthesis of K2NbO3F powders by an alternative approach of solid-state reaction

K2NbO3F powders were directly synthesized by an alternative solid-state method at low temperature. Stoichiometric ammonium niobium oxalate, K2C2O4 and KF were mixed with small amounts of water and then dried at room temperature. X-ray diffraction results show that layered perovskite K2NbO3F powders can be obtained by calcining the mixture in temperature range from 550 to 700 °C for 3 h. The elemental composition, powder morphology and particle size of calcination products were analyzed by scanning electron microscope–energy dispersive spectroscopy (SEM/EDS). The SEM images suggest that the particles of the powders obtained at 550 °C are irregular platelets with a diameter of 0.5–1 μm and a thickness of 100–200 nm. The platelets are 3–5 μm in diameter and 1–2 μm in thickness when the calcination temperature reaches 700 °C. K2NbO3F decomposes to K5(NbO3)4F and KF when the temperature reaches 800 °C.