Arrayed PbI2 clusters in the spaces of zeolite LTA

Zeolite LTA has cubic symmetry with different-sized α- and β-cages arranged in a CsCl type structure. PbI2 clusters were incorporated into the cages of LTA through a vapor phase after dehydration. The structure of this complex system was studied as a function of cluster loading by X-ray diffraction (both single crystal and powder) and by electron microscopy. The clusters were formed inside the α-cages without destroying the framework and with a maximum loading density of ca. 3.8 PbI2 clusters per α-cage. No symmetry changes were observed except for the specimens with the maximum loading. 3.8 PbI2 /LTA showed a domain structure, and more than two different types of superlattice reflections were observed. The major phase has tetragonal symmetry, P4/ncc, and the structures and the arrangements of the clusters are discussed.