Crystallographic analysis of dehydrated fully Tl+-exchanged zeolite Y

The crystal structure of Tl-71-Y (Tl71Si121Al71O384), a = 24.706(3) angstrom, dehydrated at 653 K and 8x10(-6) torr, has been determined by single-crystal X-ray diffraction techniques in the cubic space group Fd (3) over barm at 294(1) K. The structure was refined using all intensities to the final error indices (using only the 302 reflection for which F-o > 4 sigma(F-o)) R-1 = 0.0602 (based on F) and R-w = 0.1744 (based on F-2). The 71 Tl+ ions per unit cell are found at four crystallographically distinct positions. Site I' position in the sodalite cavity opposite D6Rs are each occupied by eighteen Tl+ ions per unit cell; these Tr ions are recessed ca. 1.45 angstrom into the sodalite cavity from their O(3) plane (Tl-0 = 2.701(15), 3.163(16) angstrom and O-Tl-O = 92.1(4)degrees). The 23 Tl+ ions fill site II in the supercage; these Tl+ ions are recessed ca. 1.58 angstrom into the supercage from their O(2) plane (Tl-O=2.850(16), 3.156(16) angstrom and O-Tl-O = 85.1(5)degrees). The 19 Tl+ ions lie at site III' in the supercage near a triple 4-ring (Tl-O = 3.10(7), 3.39(5) angstrom and O-Tl-O = 47.8(9), 95.3(18)degrees) and the remaining 11 ions occupy another site III' near a triple 4-ring in the supercage (Tl-O = 2.81(4), 2.71(4) angstrom and O-Tl-O = 57.3(8)angstrom).