Structure of the zeolite theta-1. Redetermination using single-crystal synchrotron-radiation data

Papiz, Miroslav Z.; Andrews, Steven J.; Damas, Ana M.; Harding, Marjorie M.; Highcock, Rona M.

doi:10.1107/s0108270189008048

Cited by 18 publications

(10 citation statements)

References 2 publications

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“…The target Si-O, O-O, and Si-Si distances and standard deviations were 1.60 ± 0.01, 2.61 ± 0.02, and 3.10 ± 0.05 Å respectively. These values are consistent with the distributions of distances compiled from the following set of single-crystal XRD structures of high-silica zeolites: Sigma-2 [3], ZSM-5 [68], Ferrierite [69], ITQ-4 [70], and Theta-1 [71] (see bottom of Fig. 4).…”

Section: Structure Refinementsupporting

confidence: 81%

A structure refinement strategy for NMR crystallography: An improved crystal structure of silica-ZSM-12 zeolite from 29Si chemical shift tensors

Brouwer

2008

Journal of Magnetic Resonance

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Section: Structure Refinementsupporting

confidence: 81%

A structure refinement strategy for NMR crystallography: An improved crystal structure of silica-ZSM-12 zeolite from 29Si chemical shift tensors

Brouwer

2008

Journal of Magnetic Resonance

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“…The calculations were performed by the QMPOT program 19 which utilizes the Turbomole program [27][28][29][30][31] for the QM part and the GULP program 23,24 for the periodic potential function calculations. The pure DFT method employing the BLYP [32][33][34] functional and the TZVP basis set of Ahlrichs 35 were used for the QM calculations. As interatomic potential functions (Pot), shell-model ion-pair potentials 36 parametrized on DFT results for zeolites 37 were employed.…”

Section: Qm-pot Methods and Programs Usedmentioning

confidence: 99%

“…A bare zeolite framework model that includes neither cations nor water molecules and has proven useful in our previous study 20 is adopted to calculate the local structure around the AlO 4 tetrahedra and to predict the 27 Al NMR shielding. The starting structure was generated from an X-ray structure of the Theta-1 zeolite 22 .…”

Section: Computational Modelmentioning

confidence: 99%

Aluminum Siting in the ZSM-22 and Theta-1 Zeolites Revisited: A QM/MM Study

Sklenák

Dědeček

et al. 2008

Collect. Czech. Chem. Commun.

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The Al siting in the silicon rich ZSM-22 and Theta-1 zeolites of the TON structure was investigated analyzing already published 27Al 3Q MAS NMR experimental data using QM/MM calculations. The results of our computations show that Al atoms can be located in 6 framework T positions because the two eightfold sites (T1 and T2) split into four fourfold T sites after an Al/Si substitution. The observed resonance at 55.5 ppm corresponds to the T4 site which is predominantly occupied by Al. This site is not located on the surface of the TON ten-membered ring channel and thus the protonic sites related with the majority of Al atoms in the TON structure exhibit a significantly limited reaction space. The 27Al NMR signals centered at 57.6 and 58.7 ppm correspond to either the T2 and T3 sites, respectively, or only to T2. The T2 and T3 sites accommodate some 40% and up to 10%, respectively, of Al while the T1 site is unoccupied by Al. Isotropic shifts of 61.1 and 61.6 ppm were calculated for Al atoms located in the T1-1 and T1-2 sites, respectively. The effect of a silanol "nest" as a next-next-nearest neighbor on the 27Al isotropic chemical shift of Al located in the T4 site is calculated to be less than 1 ppm.

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“…Superior energy storage properties have been observed for an orthorhombic 1-D siliceous zeolite TON, which has unidirectional 4.6 × 5.7 Å elliptical channels along the [001] direction. − Penetration by water molecules occurs at 186 MPa . This material undergoes a pressure-induced phase transition between Cmc 2 1 and Pbn 2 1 orthorhombic forms at close to 700 MPa.…”

Section: Introductionmentioning

confidence: 99%

Insertion and Confinement of H₂O in Hydrophobic Siliceous Zeolites at High Pressure

et al. 2019

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The insertion of H2O in the siliceous zeolites TON (Theta-one) and MFI (Mobil-Five) was studied at pressures up to 0.9 GPa by synchrotron X-ray diffraction, infrared spectroscopy and Monte Carlo Modeling. TON (orthorhombic, Cmc21) and MFI (monoclinic, P21/n) have 1D and 3D pore systems respectively. H2O insertion was quantified by a combination of structure refinements and Monte Carlo modelling. Complete pore filling is observed at 0.9 GPa in the high-pressure forms of TON (orthorhombic, Pbn21) and MFI (orthorhombic, Pnma). This corresponds to more than twice as many H2O molecules per SiO2 unit in the 3D pore system of MFI than in the 1D pore system of TON. This results in a greater swelling of the MFI system as compared to the TON system upon insertion. In both cases, both experiments and modelling indicate that the density of water in the pores is close to that of bulk water at the same pressure. A greater degree of molecular disorder is observed in the 3D network of MFI. Infrared spectroscopy indicates a weakening of the hydrogen bonds associated with geometrical constraints due to confinement. The majority of the H2O molecules are extruded on pressure release indicating that this insertion is reversible to a great extent, which gives rise to the molecular spring properties of these materials. Supporting Information. Crystallographic information files (CIF) files containing the structural data for the TON-H2O system at 0.29, 0.6 and 0.9 GPa and the MFI-H2O system at 0.31, 0.67 and 0.86 GPa have been supplied as supporting information. This material is available free of charge via the Internet at http://pubs.acs.org..

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Structure of the zeolite theta-1. Redetermination using single-crystal synchrotron-radiation data

Cited by 18 publications

References 2 publications

A structure refinement strategy for NMR crystallography: An improved crystal structure of silica-ZSM-12 zeolite from 29Si chemical shift tensors

A structure refinement strategy for NMR crystallography: An improved crystal structure of silica-ZSM-12 zeolite from 29Si chemical shift tensors

Aluminum Siting in the ZSM-22 and Theta-1 Zeolites Revisited: A QM/MM Study

Insertion and Confinement of H₂O in Hydrophobic Siliceous Zeolites at High Pressure

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Structure of the zeolite theta-1. Redetermination using single-crystal synchrotron-radiation data

Cited by 18 publications

References 2 publications

A structure refinement strategy for NMR crystallography: An improved crystal structure of silica-ZSM-12 zeolite from 29Si chemical shift tensors

A structure refinement strategy for NMR crystallography: An improved crystal structure of silica-ZSM-12 zeolite from 29Si chemical shift tensors

Aluminum Siting in the ZSM-22 and Theta-1 Zeolites Revisited: A QM/MM Study

Insertion and Confinement of H2O in Hydrophobic Siliceous Zeolites at High Pressure

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Insertion and Confinement of H₂O in Hydrophobic Siliceous Zeolites at High Pressure