Strontium and calcium zirconyl citrates as precursors for the low-temperature synthesis of SrZrO₃ and CaZrO₃ fine powders

Synthesis and the thermal decomposition behavior of new molecular precursors, strontium, and calcium zirconyl citrates are presented. The pathway to the metazirconate formation has been found to proceed through a multistep process. The precursors yield SrZrO₃ and CaZrO₃ fine powders at temperatures as low as 650 °C. Physico-chemical, spectroscopic, thermoanalytical, and microscopic techniques have enabled the identification of the sequence of events leading to the perovskite formation and proposition of a thermolysis scheme. Retention of the molecular level mixing of the metal ions during the course of the precursor decomposition is supported by these techniques. Prior to the formation of MZrO₃ (M = Sr and Ca) an ionic oxycarbonate, M₂Zr₂O₅CO₃ (M = Sr and Ca), intermediate is produced by the thermal decomposition of the citrate precursors.