Self-organized formation of seven-rod bundle morphology for lanthanum Prussian blue analog microcrystals via a precipitation process

Abstract

This article reports potassium lanthanum hexacyanidoferrate(II) microcrystals with a unique shape consisting of seven hexagonal rods. In an aqueous solution at 55 °C, [Fe(CN)₆]³⁻ ions were reduced by ascorbic acid to form [Fe(CN)₆]⁴⁻ ions, which reacted with the surrounding K⁺ and La³⁺ ions to generate K_0.82La_1.11[Fe(CN)₆]·4H₂O microcrystals. The morphology was spontaneously constructed without growth modifiers via the instantaneous precipitation of the Prussian blue analog with a hexagonal crystal structure under a specific range of reaction conditions.