Single-Crystal Structure of |Li50Na25|[Si117Al75O384]-FAU

Abstract

The single-crystal structure of fully dehydrated partially -exchanged zeolite Y, -FAU, was determined by single-crystal synchrotron X-ray diffraction techniques in the cubic space group at 100(1) K. Ion exchange was accomplished by flowing stream of 0.1 M aqueous for 2 days at 293 K, followed by vacuum dehydration at 623 K and Torr for 2 days. The structure was refined using all intensities to the final error indices (using only the 801 reflections with ( > ) . The 50 ions per unit cell are found at three different crystallographic sites. The 19 ions occupy at site I' in the sodalite cavity: the ions are recessed 0.30 into the sodalite cavity from their 3-oxygens plane (Li-O = 1.926(5) and ). The 20 ions are found at site II in the supercage, being recessed 0.23 into the supercage (Li-O = 2.038(5) and ). Site III' positions are occupied by 11 ions: these ions bind strongly to one oxygen atom (Li-O = 2.00(8) ). About 25 ions per unit cell are found at four different crystallographic sites: 4 ions are at site I, 5 at site I', 12 at site II, and the remaining 4 at site III'.