The framework topology of ZSM-12: A high-silica zeolite

LaPierre, Rene B.; Rohrman, A.C.; Schlenker, J.L.; Wood, J. D.; Rubin, Mae K.; Rohrbaugh, Wayne J.

doi:10.1016/0144-2449(85)90121-6

Cited by 158 publications

(54 citation statements)

References 5 publications

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“…Also shown are 14-ring models derived by relating MTW14MR layers by mirror planes perpendicular to the two types of 4-ring units rather than by relating the layers by translations (MTW14MR b and MTW14MR c). [29] After the appropriate space group of each topology was determined, the frameworks were optimized by energy minimizations (by using the Burchart universal force field) of the atomic coordinates and the unit cell parameters. The coordinates, unit cell parameters, and space group of each framework are given in Tables 2Sa±g in the Supporting Information.…”

Section: Ssz-59 Structure Solutionmentioning

confidence: 99%

SSZ‐53 and SSZ‐59: Two Novel Extra‐Large Pore Zeolites

Burton

Elomari

Chen

et al. 2003

Chemistry A European J

144

106

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The syntheses, structure solutions, and physicochemical and catalytic characterizations of the novel zeolites SSZ-53 and SSZ-59 are described. SSZ-53 and SSZ-59 were synthesized under hydrothermal conditions with the [1-(4-fluorophenyl)cyclopentylmethyl]trimethyl ammonium cation and 1-[1-(4-chlorophenyl)cyclopentylmethyl]-1-methyl azocanium cation, respectively, as structure-directing agents. The framework topology of SSZ-53 was solved with the FOCUS method, and the structure of SSZ-59 was determined by model building. Rietveld refinement of synchrotron X-ray powder diffraction data confirms each proposed model. SSZ-53 and SSZ-59 each possess a one-dimensional channel system delimited by 14-membered rings. Results from transmission electron microscopy, electron diffraction, catalytic experiments (spaciousness index and constraint index tests), and argon and hydrocarbon adsorption experiments are consistent with the proposed structures.

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Section: Ssz-59 Structure Solutionmentioning

confidence: 99%

SSZ‐53 and SSZ‐59: Two Novel Extra‐Large Pore Zeolites

Burton

Elomari

Chen

et al. 2003

Chemistry A European J

144

106

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show abstract

“…The proposed structure in this case (LaPierre, Rohrman, Schlenker, Wood, Rubin & Rohrbaugh, 1985) proved to have the correct topology, but refinement of the structure using synchrotron powder diffraction data was successful only after the c-axis was doubled. The synchrotron data and Weissenberg photographs from a twinned crystal showed the doubling of the c axis to be necessary and the 298i NMR spectrum showed unambiguously which of two possible space groups (C2/c and Cc with 7 and 14 T-atom positions, respectively) was the correct one (Fyfe, Gies, Kokotailo, Marler & Cox, 1990).…”

Section: Magic Angle Spinning Nmrmentioning

confidence: 99%

Zeolite crystallography. Structure determination in the absence of conventional single-crystal data

McCusker¹

1991

Acta Cryst Sect A

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Zeolite molecular sieves are a class of aluminosilicates whose technologically important properties are intimately related to their structures. Since most synthetic zeolites are only available as powders and not as single crystals, conventional crystallographic techniques cannot be used to solve their structures. The crystallographic diffÉculties are exacerbated by the pseudosymmetry, faulting, disorder and impurity problems, which are relatively common in zeolite materials. Over the years, zeolite crystallographers have developed a number of approaches to these problems and these are discussed. The techniques include informed model building, various computer approaches to model generation, application of direct methods to powder data, microcrystalline diffraction and exploitation of magic angle spinning NMR and electron microscopy. Usually a number of methods are combined to construct a framework structure model and to test it for feasibility. Once a reasonable model has been produced, Rietveld refinement will not only confirm (or reject) the framework proposal but also reveal further details of the structure. Although the techniques described were developed for application to zeolite structures, many can probably be applied to other systems.

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“…The aim of this work was to investigate whether hydroxides of the composition M(OH) 2 could replicate the chemistry seen with SiO 2 in highly siliceous zeolites, such as MFI silicalite 32 and siliceous ZSM-12 (MTW topology) 33 . The high levels of beryllium present in the frameworks found in this work, Table 1, leads to OH − :O 2 − ratios greater than unity, such that the stoichiometry of each of these frameworks tends towards a nanoporous polymorph of Be(OH) 2 .…”

Section: Discussionmentioning

confidence: 99%

Lightweight nanoporous metal hydroxide-rich zeotypes

Littlefield

Weller

2012

Nat Commun

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nanoporous materials have important industrial applications as molecular sieves, catalysts and in gas separation and storage. They are normally produced as moderately dense silicates (sio 2 ) and aluminosilicates making their specific capacities for the uptake and storage of gases, such as hydrogen, relatively low. Here we report the synthesis and characterization of lightweight, nanoporous structures formed from the metal hydroxide Be(oH) 2 in combination with relatively low levels of framework phosphate or arsenate. Three new zeotype structures are described, constructed mainly of Be(oH) 4 tetrahedra bridged through hydroxide into threemembered rings; these units link together to produce several previously unknown zeotype cage types and some of the most structurally complex, nanoporous materials ever discovered. These materials have very low densities between 1.12 and 1.37 g cm − 3 and theoretical porosities of 63-68% of their total volume thereby yielding very high total specific pore volumes of up to 0.60 cm 3 g − 1 .

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The framework topology of ZSM-12: A high-silica zeolite

Cited by 158 publications

References 5 publications

SSZ‐53 and SSZ‐59: Two Novel Extra‐Large Pore Zeolites

SSZ‐53 and SSZ‐59: Two Novel Extra‐Large Pore Zeolites

Zeolite crystallography. Structure determination in the absence of conventional single-crystal data

Lightweight nanoporous metal hydroxide-rich zeotypes

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