Open-Framework Rubidium Halides Incorporated in Cadmium Oxalate Host Lattices

The metathetic reaction between CdBr₂ and rubidium oxalate under hydrothermal conditions yields RbBr] Cd₆(C₂O₄)₆]·2H₂O, I, containing Cd₆O₂₄ clusters with the Br⁻ ions in the center. The RbBr moiety forms a three-dimensional Fm3m structure, but with a unit cell double that of the normal stable phase. The hydrothermal reaction between rubidium oxalate and CdCl₂ in the presence of NO⁻₃ ions gives Rb₂Cd(NO₃)(Cl)(C₂O₄)(H₂O)], II, containing cadmium chloro-oxalate layers. The Rb⁺ ions present between the layers interact with the Cl atoms to form a one-dimensional RbCl chain decorated by NO⁻₃ groups.