Formation and thermal stability of some metastable Dion-Jacobson related double-layered perovskites

CHED 1168

Andrew T. Hermann, atherma1@uno.edu and John B. Wiley, jwiley@uno.edu. Department of Chemistry, University of New Orleans, 2000 Lakeshore Dr, New Orleans, LA 70148
Both the formation and thermal stability of the Dion-Jacobson-related double-layered perovskites, ALaNb2O7 (A = Li, Na) and (FeCl)LaNb2O7, are investigated. These compounds are made by ion exchange reactions that start with RbLaNb2O7. While the reactions appear to be simple double displacements, the pathways for these syntheses have not been extensively studied. Similarly, while it is known that each of this series is metastable, decomposing above 600 °C, details on the transitions have not been reported. Here we use X-ray powder diffraction and differential scanning calorimetry to examine the ion exchange and decomposition reaction pathways of these materials. Thermal data will be presented in both cases and possible reaction pathways discussed.