La 2.50K 1.50IrO 7: An example of an [formula omitted] member of the [ A nB n−1O 3n][ [formula omitted]] family of perovskite-related oxides

Abstract

Single crystals of a new lanthanum potassium iridate, La 2.50K 1.50IrO 7, have been grown from a molten hydroxide flux. The structure, which is best described as resulting from the stacking of [ AO 3] and mixed [ A 2O] layers, is an n = 2 member of the [ A nB n −1O 3 n ] [ A 2 ′ O ] family of perovskite-related oxides. La 2.50K 1.50IrO 7 is comprised of [La 2IrO 6] layers containing isolated [IrO 6] octahedra and these layers are separated by a [La 0.50K 1.50O] + layer. The compound crystallizes in the R 3 ¯ space group with a = 5.7330 ( 2 ) Å and c = 18.8328 ( 9 ) Å