Three crystal structures of dehydrated Cd(II) and Rb(I) exchanged zeolite A, and have been determined by single-crystal X-ray diffraction techniques. Their structures were solved and refined in the cubic space group Pm3m at All crystals were ion exchanged in flowing streams of mixed and aqueous solution with total concentration of 0.05 M. All crystals were dehydrated at ca. and Torr for 2 days. In all of these structures, ions are found on threefold axes, each nearly at the center of a 6-oxygen ring. The first three ions per unit cell preferentially associate with 8-oxygen rings, and additional ions, if present, are found on threefold axes in the large cavity. The final and values for the three structures are 0.087 and 0.079, 0.059 and 0.067, and 0.079 and 0.095, respectively.