23Na MAS NMR Evidence for a New Sodium Cluster and Na.cntdot. in Metal-Loaded Zeolites

Nakayama, H.; Klug, D. D.; Ratcliffe, Christopher I.; Ripmeester, John A.

doi:10.1021/ja00100a064

Cited by 29 publications

(21 citation statements)

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“…The same procedure leaves the 27 Al spectrum of SES practically unchanged, showing that Na 4 31 centers inside the sodalite crystallites are air resistant. From this, it follows that the temperature-independent 50 ppm resonance, which was also observed in sodium-doped zeolite Y [19], belongs to a certain diamagnetic sodium species on the zeolite surface that may form during zeolite exposure to sodium vapor.…”

mentioning

confidence: 72%

“…By substituting A 0 2.8 mT for a typical value of sodium hyperfine coupling constant in Na 4 31 , the 23 Na NMR resonance in SES should be expected at around 10 4 ppm. As in the recent NMR study of sodium-doped zeolite Y [19], no such resonance has been found in SES. This is presumably due to a fast electron-mediated spin-lattice relaxation rate that may severely broaden the sodium resonance.…”

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confidence: 73%

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Evidence for an Antiferromagnetic Transition in a Zeolite-Supported Cubic Lattice ofFCenters

et al. 1998

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Evidence for a bcc lattice of F centers in sodium-electro-sodalite (SES), synthesized by exposing dehydrated sodalite to sodium vapor, is presented. A high electron spin density in SES produces isotropic contact shifts in nuclear magnetic resonance (NMR) spectra of the framework nuclei whose magnitude is a discrete function of local electron density. Strong exchange coupling between unpaired electrons gives rise to an antiferromagnetic phase transition in SES at T N 48 6 2 K, providing the first example of an s-electron antiferromagnet. [S0031-9007(98)

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confidence: 72%

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confidence: 73%

Evidence for an Antiferromagnetic Transition in a Zeolite-Supported Cubic Lattice ofFCenters

et al. 1998

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“…However, several experiments exist that indicate the existence of such entities (e.g. potassides) even in the solid state (Tinkham & Dye, 1985;Nakayama et al, 1994;Terskikh et al, 2001), so it is conceivable that these ions might coexist in other compounds, regardless of the fact that such entities could be (or not) identified in conventional diffraction experiments.…”

Section: The Phases Of Na 2 S and Their Related Oxidesmentioning

confidence: 99%

Pseudoatoms and preferred skeletons in crystals

Vegas

García-Baonza

2007

Acta Crystallogr Sect B

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The generalization of the Zintl–Klemm concept provides a universal formulation of a crystal structure in terms of universal building skeletons formed by Klemm's pseudoatoms: atoms that behave structurally according to their formal total electron charge. An important difference in this novel view is that charge is considered to be transferred, in the strict Zintl's sense, from the donor cations to the building skeleton as a whole, not specifically to a given atom or ion. Although application is restricted to (IV)–(IV) compounds (group 14 structures), the principle seems to be universal and can be applied to understand, to relate and to predict the structure of complex compounds on the basis of more simple structures, e.g. a given AB skeleton provides the building block for A 2 B, AB 2, ABX m etc. compounds of a very different nature. The application of such a principle only requires information on the constituent atoms and on the existing phases of the p-block elements (observed under ambient and high-pressure and/or high-temperature conditions). The ideas introduced here demonstrate, for the first time, that a generalization of the Zintl–Klemm concept is possible and that such a generalization helps to establish a univocal link between chemical composition (in terms of pseudoatoms) and the crystalline structures observed experimentally.

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“…Thus, M + and M À species might coexist in the same compound. Several experiments (Tinkham & Dye, 1985;Nakayama et al, 1994;Terskikh et al, 2001) have shown that such entities, e.g. potassides, could exist even in the solid state.…”

Section: Knas and Nalisementioning

confidence: 99%

On the charge transfer between conventional cations: the structures of ternary oxides and chalcogenides of alkali metals

Vegas

2012

Acta Crystallogr Sect B

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The structures of ternary oxides and chalcogenides of alkali metals are dissected in light of the extended Zintl-Klemm concept. This model, which has been successfully extended to other compounds different to the Zintl phases, assumes that crystal structures can be better understood if the cation substructures are contemplated as Zintl polyanions. This implies the occurrence of charge transfer between cations, even if they are of the same kind. In this article, the charge transfer between cations is even more illustrative because the two alkali atoms have different electronegativity, so that the less electropositive alkali metal and the O/S atom always form skeletons characteristic of the group 14 elements. Thus, partial structures of the zincblende-, wurtzite-, PbO- and SrAl(2)-type are found in the oxides/sulfides. In this work, such an interpretation of the structures remains at a topological level. The analysis also shows that this interpretation is complementary to the model developed by Andersson and Hyde which contemplates the structures as the intergrowth of structural slabs of more simple compounds.

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23Na MAS NMR Evidence for a New Sodium Cluster and Na.cntdot. in Metal-Loaded Zeolites

Cited by 29 publications

References 0 publications

Evidence for an Antiferromagnetic Transition in a Zeolite-Supported Cubic Lattice ofFCenters

Evidence for an Antiferromagnetic Transition in a Zeolite-Supported Cubic Lattice ofFCenters

Pseudoatoms and preferred skeletons in crystals

On the charge transfer between conventional cations: the structures of ternary oxides and chalcogenides of alkali metals

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