CRYSTAL-STRUCTURE OF DEHYDRATED CESIUM-EXCHANGED AND THALLIUM-EXCHANGED ZEOLITE-A

The crystal structure of vacuum-dehydrated Cs9Tl3Si12Al12O48, zeolite A with all Na+ ions replaced by Cs+ ions and Tl+ ions as indicated, has been determined by single-crystal X-ray diffraction experiments in the cubic space group Pm3m (a = 12.312(3) Å). The final weighted R index is 0.067. The nine Cs+ ions are distributed over four crystallographically distinct sites. Six of these are located on threefold axes in the large cavity two are 2.08 Å from the planes of 6-ring oxide ions, and the remaining four are 1.39 Å, substantially closer, from their corresponding planes. Three other Cs+ ions occupy 8-ring sites: one is at the center of an oxygen 8-ring, and the two others are located off the planes of their 8-rings. Two Tl+ ions occupy threefold-axis positions inside the sodalite unit, and the third is in the large cavity opposite a 4-ring. The Cs+ and Tl+ content of the crystal whose structure was determined is supported by X-ray fluorescence analysis. © 1979 American Chemical Society.