Synthesis and structural refinement of fully dehydrated fully Zn2+-exchanged zeolite Y (FAU), |Zn35.5|[Si121Al71O384]-FAU

The single-crystal structure of vertical bar Zn-35.5 vertical bar [Si121Al71O384]-FAU per unit cell, a = 24.794(1), dehydrated at 673 K and 1 x 10(-6) Torr, has been determined by single-crystal X-ray diffraction techniques in the space group Fd (3) over barm at 294(1) K. The structure was refined using all intensities to the final error indices (using the 930 reflections for which F-o > 4 sigma(F-o)) R-1 = 0.0448 (based on F) and wR(2) = 0.1545 (based on F-2). About 35.5 Zn2+ ions per unit cell are found at an unusually large number of crystallographic distinct positions, six. The 0.5 Zn2+ ion per unit cell is located at the center of double 6-ring (D6R, site I; Zn(I)-O(3) = 2.642(3) angstrom and O(3)-Zn(I)-O(3) = 81.23(12) and 98.77(12)degrees). Two different site-I' positions (in the sodalite cavities opposite D6Rs) are occupied by 14 and 3 Zn2+ ions per unit cell, respectively; these Zn2+ ions are recessed 0.67 angstrom and 1.02 angstrom, respectively, into the sodalite cavities from their 3-oxygens plane (Zn(I'a)-O(3) = 2.094(3) angstrom, Zn(I'b)-O(3) = 2.23(5) angstrom, O(3)-Zn(I'a)-O(3) = 110.32(12)degrees, and O(3)-Zn(I'b)-O(3) = 100.9(30)degrees). Site-II' positions (in the sodalite cavities opposite S6Rs) are occupied by 6 Zn2+ ions, each of which extends 0.63 angstrom into the sodalite cavities from their 3-oxygens plane (Zn(11')-O(2) = 2.164(3) angstrom and O(2)-Zn(II')-O(2) = 112.00(12)degrees). Twelve Zn2+ ions are found at two nonequivalent sites II (in the supercage) with occupancies of 7 and 5 ions, respectively; these Zn2+ ions are recessed 0.52 angstrom and 0.96 angstrom, respectively, into the supercage from their 3-oxygens plane (Zn(IIa)-O(2) = 2.138(12) angstrom, Zn(IIb)-O(2) = 2.28(4) angstrom, O(2)-Zn(Ha)-O(2) = 114.2(10)degrees, and O(2)-Zn(IIb)-O(2) = 103.7(25)degrees).