Synthesis of potassium niobate from metal alkoxides

Article abstract of DOI:10.1111/j.1151-2916.1991.tb07296.x

Preparation of potassium niobate from metal alkoxides was investigated. Potassium-niobium ethoxide, KNb(OC₂H₅)₆, and potassium-niobium propoxide, KNb(OC₃H₇)₆, were synthesized and subsequently hydrolyzed using several water concentrations (0.75 to 6.0 mol of water/(mol of alkoxide)). Rapid precipitation of potassium-deficient particles occurred when higher concentrations of water were used. This resulted in the formation of a multiphase material after calcination, as X-ray diffraction showed the presence of both KNbO₃ and potassium-deficient oxide phases(s). Single-phase KNbO₃ could be prepared by two methods: (1) hydrolysis of KNb(OC₃H₇)₆/propanol solutions using 1 mol of water (per mole of propoxide) added as a water/propanol solution and (2) hydrolysis of KNb(OC₂H₅)₆/ethanol solutions using 1 mol of water (per mole of ethoxide) added as a water/methanol solution. The latter method provided advantages of low calcination temperature for the formation of single-phase KNbO₃ and low weight loss after calcination.