Potassium zirconium oxalate a new precursor for the preparation of perovskite, pyrochlore and Nasicon type materials

摘要

A new precursor, potassium zirconium oxalate pentahydrate, K-4[Zr(C2O4)(4)]center dot 5H(2)O, was used for the preparation of zirconium containing perovskite, pyrochlore and Nasicon type materials. Perovskites (BaZrO3, CaZrO3, SrZrO3 and PbZrO3) were prepared by the thermal decomposition of a mixture of potassium zirconium oxalate penta-hydrate and MCl2 (M = Ba, Ca, Pb and Sr), Pyrochlore type materials, Ln(2)Zr(2)O(7) (Ln = Pr, Nd and Gd) were synthesized by heating a mixture of potassium zirconium oxalate pentahydrate and LnCl(3). Nasicon type composition, KZr2(PO4)(3) was obtained using potassium zirconium oxalate pentahydrate and phosphoric acid by hydrothermal method. Hydrothermal treatment of potassium zirconium oxalate pentahydrate in basic, neutral and acidic medium gave different products. A compound, ZrO(C2O4)center dot xH(2)O (x = 1.2-1.8), was obtained from hydrothermal heating of parent potassium zirconium oxalate pentahydrate in acid medium. The TGA profile of ZrO(C2O4)center dot xH(2)O was recorded. All the prepared compositions were characterized by powder X-ray diffraction technique. The composition ZrO(C2O4)center dot xH(2)O was characterized by Fourier-transform infrared spectroscopy, elemental analysis, XPS and powder XRD techniques. The advantages of this precursor over other zirconium containing compounds and reasons for the formation of final products are discussed.