SYNTHESIS AND CHARACTERIZATION OF BARIUM BIS(CITRATO) OXOZIRCONATE(IV) TETRAHYDRATE - A NEW MOLECULAR PRECURSOR FOR FINE-PARTICLE BAZRO3

Barium metazirconate (BaZrO3) fine powder has been produced by thermal ly decomposing a molecular precursor, barium bis(citrato)oxozirconate( IV) tetrahydrate at about 700-degrees-C. The precursor, Ba[ZrO(C6H6O7) 2] . 4H2O (BZO) has been synthesized and characterized by employing a combination of spectroscopic and thermoanalytical techniques. The prec ursor undergoes thermal decomposition in three major stages: (i) dehyd ration to give an anhydrous barium zirconyl citrate, (ii) decompositio n of the anhydrous citrate in a multistep process to form an ionic oxy carbonate intermediate, Ba2Zr2O5CO3, and (iii) decomposition of the ox ycarbonate to produce BaZrO3 fine powder. The particle size of the res ultant BaZrO3 is about 0.2 mum, and the surface area is found to be 4. 0 m2 g-1.