Crystal structures of the potassium clusters in the sodalite cavities of zeolites A and X

Sun, Tao; Seff, Karl

doi:10.1021/j100122a007

Cited by 30 publications

(21 citation statements)

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“…It is possible that In 2 O, from the decomposition of surface In 2 O 3 on the original In sample, mediated the transport of In to the surface of the zeolite . Except for this reversed temperature gradient during the reaction period, other experimental procedures for the reaction were similar in detail to those previously described for solvent free ion-exchange. − …”

Section: Methodsmentioning

confidence: 99%

Crystal Structure of Indium-Exchanged Zeolite A Containing Sorbed Disulfur

et al. 1998

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Molecules of S2 are sorbed by dehydrated fully indium exchanged zeolite A from S(g) at 623 K. The crystal structure of dehydrated In8Si12Al12O48·(In)0.75(S2) (R 1 = 0.053, R 2 = 0.050, and a = 12.090(2) Å) has been studied by single-crystal X-ray diffraction methods at 294 K using the space group Pm3̄m. The complex structural results are interpreted as follows. Each unit cell contains eight indium cations, 0.75 indium atoms, and two sulfur atoms. Six In ions per unit cell are found at four nonequivalent 3-fold axis equipoints: two In+ ions and 0.5 In3+ ions lie opposite six-rings in the large cavity, and three In2+ ions and 0.5 In+ ions lie opposite six-rings in the sodalite unit. Two In+ ions per unit cell are found at eight-ring positions, off the plane. Three-quarters of an indium per unit cell, as near-neutral atoms associated with In2+ cations, are found at the centers of the sodalite units. The distances of In+, In2+, and In3+ to the nearest framework oxygens are ca. 2.55, 2.37, and 2.26 Å, respectively. The structure may be viewed as having two kinds of “unit cells.” Unit cell 1 (In8-A·(In)(S2), 75%) contains the (In5)8+ cluster (four In2+ ions tetrahedrally arranged about an In0 in the sodalite unit (In2+−O = 2.37(1) Å and In0−In2+ = 2.75(2) Å)). Unit cell 2 (In8-A·(S2), 25%) has two In3+ ions. In each large cavity, one atom of a disulfur molecule (S−S = 2.13(13) Å) associates with three framework oxygens at 3.11(11) Å, and the other sulfur atom bridges between two In+ ions at 3.26(3) and 3.37(19) Å.

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Section: Methodsmentioning

confidence: 99%

Crystal Structure of Indium-Exchanged Zeolite A Containing Sorbed Disulfur

et al. 1998

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“…In such a case, the molecule in the cage may show interesting properties, which are not seen under ordinary conditions. It is very important to investigate the steric restriction of a molecule in a zeolite cage; there have been many reports [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] on this subject. However, it is noteworthy that most reports have dealt with a steric restriction of molecules that are smaller than the zeolite cages.…”

Section: Introductionmentioning

confidence: 99%

Structural Distortion of 6-Coordinated Fe(II) Complexes in Zeolite Y

1999

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Six-coordinated Fe(II) complex ions [FeL3]2+ (L = en, amp, bpy, dmbpy, phen, and dmphen), prepared in a supercage of zeolite Y, were characterized by UV−vis, XRD, Mössbauer spectroscopy, and IR. The UV−vis spectra and XRD patterns of the zeolite encapsulating the Fe(II) complex ions show that [Fe(en)3]2+, [Fe(amp)3]2+, [Fe(bpy)3]2+, and [Fe(phen)3]2+ are formed in the zeolite supercage. The Mössbauer spectra of [Fe(bpy)3]2+ and [Fe(phen)3]2+ in the supercage gave extraordinarily large values of the quadrupole splitting for low-spin Fe(II) species, indicating that these complex ions in a supercage are distorted by a strong steric interaction with the zeolite lattice. The IR spectra of [Fe(bpy)3]2+ and [Fe(phen)3]2+ in the supercage as well as their Mössbauer results reveal that the complex ion is located in the supercage; (i) the 3-fold axis of the complex is parallel to that of the supercage, (ii) each of the three bidentate-ligand molecules in the complex faces to the 12-membered ring of the supercage, and (iii) the complex is twisted around its 3-fold axis toward a trigonal prism.

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“…When zeolites containing alkali-metal cations are exposed to an alkali-metal vapor, sorption, − and sometimes redox reaction, − can occur. When excess atoms are sorbed, their valence electrons delocalize to various degrees to form cationic clusters within the cavities of the zeolite.…”

Section: Introductionmentioning

confidence: 99%

Crystal Structure of a Sodium Sorption Complex of Zeolite X Containing Linear Na₃²⁺Clusters

Shibata

Seff

1997

J. Phys. Chem. B

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An anhydrous single crystal of sodium zeolite X, Na92Si100Al92O384, was exposed for 48 h to Na vapor at 225 °C. Its structure was determined by X-ray diffraction methods in the cubic space group Fd3̄; a = 25.100(11) Å at 22 °C; R 1 = 0.071 and R 2 = 0.088 for the 544 reflections for which I > 3σ(I). A total of 106 sodiums are found per unit cell, 14 more than the number of Na+ ions required to balance the negative charge of the zeolite framework. The same number, 14, of Na atoms are found at the very centers of 12-oxygen rings, far from the zeolite framework. It appears that each Na atom has been captured by a pair of Na+ ions to form linear Na3 2+ clusters that nearly fill the 12-oxygen rings. Each terminal sodium approaches two oxygens of an AlO4 tetrahedron of the zeolite framework with Na−O distances of 2.33(3) and 2.83(4) Å. Although some delocalization of the single valence electron over this cluster must occur, it is recognized, from the sodium approach distances to framework oxygens, that the terminal sodiums are largely cationic and the central sodium is closer to neutral. The bond lengths in the cluster are 2.93(3) Å, about the same as the corresponding distance in Na5 4+, 2.80(2) Å, and the sum of the radii of Na0 and Na+, 2.83 Å.

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Crystal structures of the potassium clusters in the sodalite cavities of zeolites A and X

Cited by 30 publications

References 3 publications

Crystal Structure of Indium-Exchanged Zeolite A Containing Sorbed Disulfur

Crystal Structure of Indium-Exchanged Zeolite A Containing Sorbed Disulfur

Structural Distortion of 6-Coordinated Fe(II) Complexes in Zeolite Y

Crystal Structure of a Sodium Sorption Complex of Zeolite X Containing Linear Na₃²⁺Clusters

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Crystal structures of the potassium clusters in the sodalite cavities of zeolites A and X

Cited by 30 publications

References 3 publications

Crystal Structure of Indium-Exchanged Zeolite A Containing Sorbed Disulfur

Crystal Structure of Indium-Exchanged Zeolite A Containing Sorbed Disulfur

Structural Distortion of 6-Coordinated Fe(II) Complexes in Zeolite Y

Crystal Structure of a Sodium Sorption Complex of Zeolite X Containing Linear Na32+Clusters

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Crystal Structure of a Sodium Sorption Complex of Zeolite X Containing Linear Na₃²⁺Clusters