Understanding Si/Al distributions in Al-rich zeolites: the role of water in determining the structure of Goosecreekite

Almora‐Barrios, Neyvis; Gómez, Ariel; Ruiz‐Salvador, A. Rabdel; Mistry, Manisha; Lewis, Dewi W.

doi:10.1039/b009623g

Cited by 27 publications

(26 citation statements)

References 11 publications

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“…This procedure has been proven to be particularly useful for modelling zeolitic materials. [41][42][43] To reduce the size-effect contribution in the error of averaged observables we have designed an ensemble of special quasirandom structures (SQS's), [44] that mimic the average in composition of the calculated structures and radial correlation functions of optimised structures for each molar fraction. The generation of these structures take into account the free energy of the unit cell for each Ge content and correlation functions.…”

Section: Theoretical Methodologymentioning

confidence: 99%

The Si–Ge substitutional series in the chiral STW zeolite structure type

et al. 2018

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Section: Theoretical Methodologymentioning

confidence: 99%

The Si–Ge substitutional series in the chiral STW zeolite structure type

et al. 2018

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“…[19][20][21] The complete refinement of the pseudosymmetric structure of a hydrated Na-A zeolite has been carried out, by x-ray measurements, by Gramlich and Meier. These molecules greatly influence the position of exchangeable cations and as a result the chemical properties of the zeolite.…”

Section: Methodsmentioning

confidence: 99%

T dependence of vibrational dynamics of water in ion-exchanged zeolites A: A detailed Fourier transform infrared attenuated total reflection study

Crupi

Longo

Majolino

et al. 2005

The Journal of Chemical Physics

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In order to explore the influence of cation substitution on the vibrational dynamics of water molecules in zeolites, the evolution of structural properties of the O-H stretching band of water in fully hydrated Na-A and Mg-exchanged A zeolites has been studied, for different percentages of induced ion exchange, by Fourier transform infrared attenuated total reflection spectroscopy as a function of temperature. The differences revealed in the O-H stretching band shapes have been accounted by fitting the spectra as a sum of four components, corresponding to water molecules exhibiting different types of hydrogen bonding. The dependencies of the relative intensities, peak wave numbers, and bandwidths of the resolved components on temperature and Mg2+ content have been discussed. Evidence of the "structure-maker" role played by a zeolitic surface on physisorbed water, systematically enhanced by increasing the percentage of induced ion exchange, is given in the whole explored temperature range.

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“…[9] However, we believe that we have made significant progress in this field recently, demonstrating that we are both able to reproduce experimental structures and also to provide thermochemical mechanisms for cation and framework compositions. [10,11] The simulations are based on the classical Born model of solids with interatomic potentials describing the forces between the atoms. Energy minimizations were performed with the GULP program, [12] by using the potential parameters described by Jackson and Catlow [13] and de Leeuw et al, [14,15] with minor modifications by Lewis et al [11] We have already successfully modeled a number of hydrated calcium-bearing zeolites [10,11] using these parameters and methods.…”

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confidence: 99%

Pressure‐Induced Hydration Effects in the Zeolite Laumontite

White¹,

Ruiz‐Salvador²,

Lewis³

2004

Angew Chem Int Ed

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The hydration level of minerals is an important indicator of the conditions prevailing during their formation and during any subsequent geological transformation. The precise water content of mineral zeolites, often highly sensitive to pressure and temperature due to their microporous structure, is particularly key in estimating rock porosity. The presence of the mineral zeolite laumontite near petroleum deposits, for example, can significantly reduce rock permeability, which may limit the production potential of the reservoir.[1] However, since laumontite readily partially dehydrates at ambient conditions [1,2] the exact composition during formation and subsequent diagenesis remains a key question. Neuhoff and Bird [1] [3] and only becomes fully hydrated at elevated pressures. Lee et al. [4][5][6] recently showed that another natural zeolite, natrolite, undergoes pressure-induced overhydration. As a consequence, it is imperative that we can determine the structure of such zeolites at nonambient conditions if we are to understand, not only their geochemistry, but also to assess the impact of extreme conditions on their suitability as, for example, nuclear-waste-containment and barrier materials. Here, we show using computational methods that laumontite can transform from the low-water "leonhardite" composition to the fully hydrated structure under the influence of pressure.Laumontite (LAU·18 H 2 O; Figure 1) is one of the more common natural zeolites. The structure comprises channels bounded by eight tetrahedral units, parallel to the c axis, that contain Ca 2+ ions coordinated to the framework and water (labeled [2] W2 and W8), together with an additional hydrogen-bonded water network (W1 and W5

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Understanding Si/Al distributions in Al-rich zeolites: the role of water in determining the structure of Goosecreekite

Cited by 27 publications

References 11 publications

The Si–Ge substitutional series in the chiral STW zeolite structure type

The Si–Ge substitutional series in the chiral STW zeolite structure type

T dependence of vibrational dynamics of water in ion-exchanged zeolites A: A detailed Fourier transform infrared attenuated total reflection study

Pressure‐Induced Hydration Effects in the Zeolite Laumontite

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