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.