Building Metal-Anion Layers within a Preovskite Host

• Main Author: Zhang, Xiao
• Format: Others
• Published: ScholarWorks@UNO 2006
• Online Access: http://scholarworks.uno.edu/td/415; http://scholarworks.uno.edu/cgi/viewcontent.cgi?article=1436&context=td

Alkali metal halide layers were constructed within Dion-Jacobson (DJ) layered perovskites by a two-step sequential intercalation method. Reductive intercalation with an alkali metal, followed by oxidative intercalation with chlorine gas, leads to the formation of compounds of the general formula, (A2Cl)LaNb2O7 (A = Rb, Cs). Rietveld refinement of X-ray powder diffraction data shows that an alkali metal halide layer is formed between the perovskite blocks. The alkali metal cation is eight-coordinate with 4 oxygens from the perovskite layer and 4 chlorides from the new halide layer; this environment is similar to cesium in the CsCl structure. Thermal analysis indicates that these are low-temperature phases where decomposition begins below 200°C. Details on the synthesis and characterization of this set of compounds are presented and the general utility of this approach discussed.