Control of the alkali cation alignment in Prussian blue framework

We found that the alignments of the alkali cations can be controlled by a distortion of Prussian blue framework; the rubidium ions form a rod structure in a distorted framework of Rb0.85Cu-[Fe(CN)(6)](0.95)center dot 1.3H(2)O, while the cesium ions are isolated dot structures in a non-distorted framework of Cs0.97Cu[Fe(CN)(6)](0.99)center dot 1.1H(2)O. The Madelung energy calculations revealed that the novel rod structure is stabilized by the alternating rotations of the [Fe(CN)(6)] units within the three-dimensional coordination polymer framework.