The Sodalite Family - A Simple but Versatile Framework Structure

Depmeier, Wulf

doi:10.2138/rmg.2005.57.7

Cited by 55 publications

(48 citation statements)

References 115 publications

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“…The framework of trigonal quartz expands under heating; the angle 144˚ of Si-O-Si is enlarged to ~180˚ in hexagonal quartz; it becomes a topological barrier, which restricts the further growth of the unit cell edges under temperature increase. The lazurite and sodalite structures are based on flexible sodalite framework, which can shrink or unfold depending on temperature [10]. Thus, when comparing the temperature dependences of unit cell edges of lazurite and sodalite we suppose that the topology of sodalite framework causes constraints for further unfolding of structure after the unit cell edge takes the value of ~9.160 Å.…”

Section: X-ray Diffractionmentioning

confidence: 99%

“…Vacuum pressure in the analysis chamber was 10 6.7 10 − × mbar. The spectrometer was equipped with an OPX-150 hemisphere detector.…”

Section: X-ray Photoelectron Spectroscopymentioning

confidence: 99%

“…The formation of modulated structures in sodalite mineral family has recently been interpreted as a result of phase transitions [5] [10]. However, the incommensurable transitions in the insulators are often subjected to "competing, short-range interatomic forces of different ranges and similar magnitude" [13].…”

Section: Itm In Terms Of Forced Equilibrium Conceptionmentioning

confidence: 99%

See 2 more Smart Citations

Reversion of Incommensurate Modulation in Cubic Lazurite: Example of Reversible Forced Equilibrium?

Таусон¹,

Сапожников²,

Канева³

et al. 2014

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The sample of cubic lazurite, collected in the Baikal region, with incommensurately 3D modulated (ITM) structure has been studied by the method of high-temperature X-ray powder diffraction. At short time of annealing in high-temperature diffraction experiment the modulation recovery proceeds during cooling down the sample to room temperature. The identity of the period of both initial and recovered modulation demonstrates that the system has a structural memory. The acquired results are interpreted through comparison of thermal behavior of lazurite, sodalite and quartz structures. It is supposed that two kinetically different and thermally activated processes proceed under heating: 1) reversible framework expansion due to Si-O-Al angle increase, and 2) equalizing of periodic local distortions via the diffusion-controlled transfer of cage ions between adjacent subcells. The second process seems to be much slower than the first one, especially at lower temperatures. With increasing temperature, both processes are activated. However, the framework expands more rapidly than the cage clusters migrate, and the periodic distortions of the framework are aligned. Under lower temperatures, the framework shrinks and again accommodates to the configuration of cage cations (clusters), which may be changed at high temperature and sufficient time or may not at lower temperature, short time, unfavorable SO2 fugacity values. In the first case the modulation disappears entirely, while in the second case it arises again. The probable reason for ITM formation is the balance of counteracting energetic terms: the elastic strain energy of structure deformation and the energy of cluster ordering providing the state of forced equilibrium. The excess free energy due to structure distortion is compensated by the increment associated with the cluster ordering process. However, no significant variations in sulphur anion speciation for different degrees of modulation retention were observed by XPS S 2p. This may be due to the ordering of Na-and Ca-containing clusters rather than the clusters with different sulphur species. ITM reversion is considered as an example of reversible forced equilibrium with completely reproducible forcing factor.

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Section: X-ray Diffractionmentioning

confidence: 99%

“…Vacuum pressure in the analysis chamber was 10 6.7 10 − × mbar. The spectrometer was equipped with an OPX-150 hemisphere detector.…”

Section: X-ray Photoelectron Spectroscopymentioning

confidence: 99%

Section: Itm In Terms Of Forced Equilibrium Conceptionmentioning

confidence: 99%

See 1 more Smart Citation

Reversion of Incommensurate Modulation in Cubic Lazurite: Example of Reversible Forced Equilibrium?

Таусон¹,

Сапожников²,

Канева³

et al. 2014

View full text Add to dashboard Cite

show abstract

“…However, faujesite, Zeolite X, and Zeolite P, all have the identical cage structure as sodalite. [119] So while the sodalite in the FBSR mineral phases may be attracting structural waters of hydration to its structure the sodalite cage structure appears to remain in tact. Another zeolite, known as N3 or Zeolite Na-P1, was also observed but also forms from the alteration of fly ash according to the Australian study [118].…”

Section: Product Consistency Test (Pct) -Long Term On Fbsr Monolithsmentioning

confidence: 99%

Radioactive Demonstration Of Mineralized Waste Forms Made From Hanford Low Activity Waste (Tank Farm Blend) By Fluidized Bed Steam Reformation (FBSR)

Jantzen

Crawford

Bannochie

et al. 2013

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“…The latter, experimentally known polymorph (ZIF-72) [25] represents the ground state among the considered structures. Framework SOD-I in cubic space group Im3 ̅ m represents the fully expanded conformational state with the lowest density [26], while the denser conformers SOD-II (cubic I4 ̅ 3m) and SOD-III (trigonal R3 ̅ ) show different kinds of distortion from the maximal-symmetry framework. The latter two conformers resemble the framework conformations found in the low-and high-pressure forms of ZIF-8 [27][28][29][30][31] and guestfree/guest-containing forms of [Zn(bim) 2 ]-SOD (ZIF-7) with the benzimidazolate (bim) linker [28,[32][33][34], respectively.…”

Section: Energy Landscape Of the [Zn(dcim) 2 ] System Considering Topmentioning

confidence: 99%

The ZIF system zinc(II) 4,5-dichoroimidazolate: theoretical and experimental investigations of the polymorphism and crystallization mechanisms

Springer

Heidenreich

Stock

et al. 2016

Zeitschrift Für Kristallographie - Crystalline Materials

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Abstract:In this report, we summarize our theoretical and experimental investigations on the zeolitic imidazolate framework (ZIF) system [Zn(dcim) 2 ] (dcim = 4,5-dichloroimidazolate) that have been published recently. These comprise: (1) a theoretical study on hypothetical conformational [Zn(dcm) 2 ]-SOD polymorphs with the same underlying sodalite (SOD) topology but distinct dcim linker orientations, (2) a synthetic work that resulted in the experimental realization of the most stable predicted (trigonal) SOD-type framework conformer and improved synthetic protocols for a previously discovered cubic SOD-type material, (3) a detailed structural analysis of the trigonal and cubic SOD-type materials, (4) a comparative characterization of the SOD-type materials by gas physisorption measurements, (5) a synthetic work that resulted in the discovery of a complete series of intermediate frameworks with the trigonal and cubic SOD-type materials as the end members, and (6) time-resolved insitu light and stopped-flow synchrotron small-angle and wide-angle X-ray scattering experiments on the rapid crystallization of the RHO-type polymorph (ZIF-71). In addition, we report as yet unpublished work, concerning time-resolved in-situ angular-dispersive synchrotron X-ray diffraction experiments on RHO-/SOD-type phase selection via the coordination modulation approach during competitive formation of the RHO-type and SOD-type materials.

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The Sodalite Family - A Simple but Versatile Framework Structure

Cited by 55 publications

References 115 publications

Reversion of Incommensurate Modulation in Cubic Lazurite: Example of Reversible Forced Equilibrium?

Reversion of Incommensurate Modulation in Cubic Lazurite: Example of Reversible Forced Equilibrium?

Radioactive Demonstration Of Mineralized Waste Forms Made From Hanford Low Activity Waste (Tank Farm Blend) By Fluidized Bed Steam Reformation (FBSR)

The ZIF system zinc(II) 4,5-dichoroimidazolate: theoretical and experimental investigations of the polymorphism and crystallization mechanisms

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