Crystal structure of partially desolvated (NiOH+)2(NH4+)10-A, with some discussion of the fully solvated structure

Patalinghug, WC; Seff, K.

doi:10.1021/j100382a063

Cited by 8 publications

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“…The final cycles of refinement were done with anisotropic temperature factors for all positions except for O(3b) and O (5) and with the final refined weighting-scheme parameters (see Table 1). The final error indices R 1 and R 2 are given in Table 1.…”

Section: Structure Determinationmentioning

confidence: 99%

“…The single-crystal structures of several NH 4 + -exchanged A (LTA) and X (FAU with Si/Al < 1.5) zeolites have been reported. − McCusker et al investigated fully dehydrated, fully NH 4 + -exchanged zeolite A by single-crystal X-ray diffraction methods and reported the positions of the NH 4 + ions . Their single crystal was prepared by the flow method using 1.0 M NH 4 NO 3 for 72 h at 298 K, followed by evacuation at 298 K and 10 -5 Torr; this resulted in the complete dehydration of NH 4 -A with no NH 4 + decomposition.…”

Section: Introductionmentioning

confidence: 99%

“…(They had added ammonia to their ion-exchange solutions to avoid crystal damage from the protons arising from the hydrolysis of Cu 2+ .) Patalinghug et al reported a structure of Ni 2+ - and NH 4 + -exchanged zeolite A . Zhen et al.…”

Section: Introductionmentioning

confidence: 99%

“…Patalinghug et al reported a structure of Ni 2+ -and NH 4 + -exchanged zeolite A. 5 Zhen et al prepared anhydrous NH 4 + -exchanged zeolite X, allowed it to react with HgCl 2 vapor at 388 K, and determined the resulting structure. 6 H-Y has both Bronsted and Lewis acid sites.…”

Section: Introductionmentioning

confidence: 99%

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Six Single-Crystal Structures Showing the Dehydration, Deamination, Dealumination, and Decomposition of NH₄⁺-Exchanged Zeolite Y (FAU) with Increasing Evacuation Temperature. Identification of a Lewis Acid Site

and¹,

Seo²,

and³

et al. 2007

J. Phys. Chem. C

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Single crystals of zeolite Y, |Na 71 |[Si 121 Al 71 O 384 ]-FAU, with diameters up to 0.20 mm were grown. They were ion exchanged to generate |(NH 4 ) 64 Na 5 K 2 |[Si 121 Al 71 O 384 ]-FAU. Crystals 1 through 6, respectively, were vacuum dehydrated at 323, 373, 423, 473, 523, and 573 K, and without reexposure to the atmosphere, their structures were determined crystallographically at 294 K using synchrotron X-radiation. Their compositions (best integers) are seen to be respectively |(NH 4 ) 59 H 5 Na 5 K 2 (H 2 O) 3 |[Si 121 Al 71 O 384 ]-FAU (incomplete dehydration and partial deamination), |(NH 4 ) 31 H 33 Na 5 K 2 |[Si 121 Al 71 O 384 ]-FAU (further deamination), |(NH 4 ) 2 H 62 Na 5 K 2 |[Si 121 -Al 71 O 384 ]-FAU (nearly complete deamination), |H 61 Na 5 K 2 (Al 2 O) 0.5 |[Si 122 Al 70 O 384 ]-FAU (onset of dealumination and framework reconstruction), |H 53 Na 5 K 2 (Al 2 O) 2 |[Si 124 Al 68 O 384 ]-FAU (further dealumination and reconstruction), and |H 51 Na 5 K 2 (Al 2 O) 2.5 |[Si 124 Al 68 O 384 ]-FAU. The extent of deamination of NH 4 + increases with increasing evacuation temperature until it is complete in crystal 4. In crystal 1, 59 NH 4 + ions per unit cell are found at two crystallographically distinct positions: 30 at site I′ (in sodalite cavities opposite D6Rs) and 29 at site II (in supercages opposite S6Rs). Three water molecules coordinate to Na + ions. In crystal 2, 17 NH 4 + ions per unit cell are found at site I′ and 13 at site II. In crystal 3, only 2 NH 4 + ions at site II are found. The extent of dealumination of the zeolite framework, seen in crystals 4, 5, and 6, also increases with temperature: 1, 4, and 5 Al 3+ ions per unit cell, respectively, are found at site I′ recessed slightly into D6Rs. Each Al 3+ ion coordinates trigonally (O-Al-O ) 119.3°) at ca. 1.85 Å to three framework oxygens. Pairs of these Al 3+ ions are each bridged by a nonframework oxide ion at the center of a D6R to give linear Al-O-Al groups (Al-O ) 1.62 Å). These Al 3+ ions are Lewis-acid sites and should be catalytically active when accessible. Five additional crystals vacuum dehydrated at 623 K and above showed no crystallinity, due presumably to further dealumination and dehydration (loss of H + and framework oxygen).

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Section: Structure Determinationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Six Single-Crystal Structures Showing the Dehydration, Deamination, Dealumination, and Decomposition of NH₄⁺-Exchanged Zeolite Y (FAU) with Increasing Evacuation Temperature. Identification of a Lewis Acid Site

and¹,

Seo²,

and³

et al. 2007

J. Phys. Chem. C

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show abstract

“…25,[71][72][73] McCusker et al investigated fully dehydrated, fully NH 4 + -exchanged zeolite A by single-crystal X-ray diffraction methods and reported the positions of the NH4 + ions. 71 Their single crystal was prepared by the flow method using 1.0 M + ion-exchange procedure was repeated 5 times with the fresh NH4C2H3O2 solution.…”

Section: Introductionmentioning

confidence: 99%

Single-crystal Structure of Fully Dehydrated and Largely NH₄⁺-exchanged Zeolite Y (FAU, Si/Al = 1.70), │(NH₄)₆₀Na₁₁│[Si₁₂₁Al₇₁O₃₈₄]-FAU

2009

Bulletin of the Korean Chemical Society

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The single-crystal structure of largely ammonium-exchanged zeolite Y dehydrated at room temperature (293 K) and 1 × 10 -6 Torr. has been determined using synchrotron X-radiation in the cubic space group Fd 3 m (a = 24.9639(2) Å) at 294 K. The structure was refined to the final error index R1 = 0.0429 with 926 reflections where Fo > 4σ(Fo); the composition (best integers) was identified as |(NH4)60Na11|[Si121Al71O384]-FAU. The 11 Na + ions per unit cell were found at three different crystallographic sites and 60 NH4 + ions were distributed over three sites. The 3 Na + ions were located at site I, the center of the hexagonal prism (Na-O = 2.842(5) Å and O-Na-O = 85.98 (12) o ). The 4 Na + and 22 NH4 + ions were found at site I' in the sodalite cavity opposite the double 6-rings, respectively (Na-O = 2.53 (13) (14) o ).

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Lta

Baur¹,

Fischer²

Zeolite-Type Crystal Structures and Their Chemistry. Framework Type Codes LTA to RHO

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Crystal structure of partially desolvated (NiOH+)2(NH4+)10-A, with some discussion of the fully solvated structure

Cited by 8 publications

References 0 publications

Six Single-Crystal Structures Showing the Dehydration, Deamination, Dealumination, and Decomposition of NH₄⁺-Exchanged Zeolite Y (FAU) with Increasing Evacuation Temperature. Identification of a Lewis Acid Site

Six Single-Crystal Structures Showing the Dehydration, Deamination, Dealumination, and Decomposition of NH₄⁺-Exchanged Zeolite Y (FAU) with Increasing Evacuation Temperature. Identification of a Lewis Acid Site

Single-crystal Structure of Fully Dehydrated and Largely NH₄⁺-exchanged Zeolite Y (FAU, Si/Al = 1.70), │(NH₄)₆₀Na₁₁│[Si₁₂₁Al₇₁O₃₈₄]-FAU

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Crystal structure of partially desolvated (NiOH+)2(NH4+)10-A, with some discussion of the fully solvated structure

Cited by 8 publications

References 0 publications

Six Single-Crystal Structures Showing the Dehydration, Deamination, Dealumination, and Decomposition of NH4+-Exchanged Zeolite Y (FAU) with Increasing Evacuation Temperature. Identification of a Lewis Acid Site

Six Single-Crystal Structures Showing the Dehydration, Deamination, Dealumination, and Decomposition of NH4+-Exchanged Zeolite Y (FAU) with Increasing Evacuation Temperature. Identification of a Lewis Acid Site

Single-crystal Structure of Fully Dehydrated and Largely NH4+-exchanged Zeolite Y (FAU, Si/Al = 1.70), │(NH4)60Na11│[Si121Al71O384]-FAU

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Six Single-Crystal Structures Showing the Dehydration, Deamination, Dealumination, and Decomposition of NH₄⁺-Exchanged Zeolite Y (FAU) with Increasing Evacuation Temperature. Identification of a Lewis Acid Site

Six Single-Crystal Structures Showing the Dehydration, Deamination, Dealumination, and Decomposition of NH₄⁺-Exchanged Zeolite Y (FAU) with Increasing Evacuation Temperature. Identification of a Lewis Acid Site

Single-crystal Structure of Fully Dehydrated and Largely NH₄⁺-exchanged Zeolite Y (FAU, Si/Al = 1.70), │(NH₄)₆₀Na₁₁│[Si₁₂₁Al₇₁O₃₈₄]-FAU