Using the Thallous Ion Exchange Method to Exchange Tin into High Alumina Zeolites. 1. Crystal Structure of |Sn²⁺_5.3Sn⁴⁺_0.8Cl^–_1.8|[Si₁₂Al₁₂O₄₈]-LTA

Abstract

Sn 2+ and Sn 4+ ions have replaced all of the Tl + ions in the zeolite Tl 12 -A (|Tl 12 |[Si 12 Al 12 O 48 ]-LTA) by thallous ion exchange (TIE), a vapor phase ion exchange method: SnCl 2 (g) was allowed to react with Tl 12 -A under anhydrous conditions at 723 K for 48 h. The tin content of the product, |Sn 2+ 5.3 Sn 4+ 0.8 Cl − 1.8 |[Si 12 Al 12 O 48]-LTA, is 32.6 wt %, much higher than previously reported for any zeolite. Its structure was determined by single-crystal crystallography at 294 K using synchrotron X-radiation (Pm3̅ m, a = 12.075(1) Å, R 1 = 0.069, R 2 = 0.224), and its composition was confirmed by scanning electron microscopy energy-dispersive X-ray analysis. Sn 2+ is found at four crystallographic positions, Sn 4+ at two, and Cl − at two. Among the 5.3 Sn 2+ ions per unit cell, 2.7 (3-coordinate) lie opposite 6-rings in large cavities, 0.3 (4-coordinate) are opposite 6-rings in sodalite cavities, 1.5 are in 8-rings, and 0.7 approach a framework oxygen atom and two chloride ions in a trigonal planar manner. Among the 0.8 Sn 4+ ions per unit cell (all 3-coordinate, from the disproportionation of Sn 2+ ), 0.7 are opposite the intersection of a 4-, a 6-, and an 8-ring in large cavity, and 0.1 are in 6-rings. Most of the Cl − ions bridge between Sn 2+ ions in the large cavity to form Sn 3 Cl 2 4+ . The rest, at the center of the sodalite cavity, bridge linearly between two Sn 2+ ions to form Sn 2 Cl 3+ .

Disproportionation of an Element in a Zeolite. III. Crystal Structure of a High-Temperature Sulfur Sorption Complex of Zeolite LTA Containing Two New Ions: Perthiosulfite, S42–, and the Trisulfur Cation, S32+

“…This is because most of the nonframework cations, including S 3 2+ , coordinate to O3 atoms (Table 5). 13,20,21 For the same reason, the T−O3−T angle is the smallest (Table 5). The numbers in parentheses are the estimated standard deviations (esds) in the units of the least significant figure given for the corresponding parameter.…”

“…As previously described, , synchrotron X-ray diffraction intensities for the single crystal were measured by the omega scan method at the Photon Factory (PF), Tskuba, Japan. The space group Pm 3̅ m , appropriate for zeolite A unless high precision is achievable, was used.…”

Crystal Structure and Luminescence of Sn,I,Cs,Na–Y, a Lead-Free Zeolite Containing Tetrahedrally Distorted Cubes of Sn4I44+

“…Sn 2+ ions have been introduced into zeolites. − Because Sn 2+ hydrolyzes extensively in aqueous solution, conventional liquid phase ion exchange (LPIE) is problematic. The LPIE of Sn 2+ has worked well only for high-silica zeolites such as mordenite (Si/Al = 5.0) and H-beta zeolite (Si/Al = 12) .…”

“…For low-silica zeolites, solvent-free vapor phase ion exchange (VPIE) has been employed. Tin chloride clusters such as Sn 2 Cl 3+ and Sn 3 Cl 2 4+ were prepared within zeolite A by the reaction of anhydrous Tl-A with SnCl 2 ( g ) at 723 K . Similarly, Sn 5 12+ , Sn 2 Cl 3+ , and Sn 3 Cl 5+ clusters were prepared within zeolite Y by VPIE at 623 K …”

Crystal Structure of Zeolite LTA Containing Extraframework Tungsten(VI) Ions

“…The objectives of this work were (1) to achieve tungsten ion exchange into a high alumina zeolite by the thallous ion exchange (TIE) method, 11 thus, bypassing the difficulties associated with conventional aqueous ion exchange, 11 and (2) to observe the positions and coordination environments of the extraframework tungsten species in the product zeolite. 18 This or similar procedures had been shown to be suitable for the preparation of the fully Tl + -exchanged zeolites Tl-A, 19,20 Tl-X, 21,22 Tl-Y, 23,24 and Tl-ZSM-5. 25 2.2.…”