Room-Temperatrue Structure and Geometrical Analysis of the Cubic–Tetragonal Phase Transition in Dodecasil 3C-THF

Knorr, K.; Depmeier, Wulf

doi:10.1107/s010876819600972x

Cited by 16 publications

(13 citation statements)

References 5 publications

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“…Thed ifference of configuration between 2-propanol and 1propanol leads to aphase transition, but this situation may not be unique for this particular guest in the 2-propanol + CH 4 system. In fact, ac lathrasil [37,38] encaging tetrahydrofuran (THF) as guest transform into tetragonal structures at lower temperatures.M oreover,s ome clathrasils show progressive symmetry-lowering as the temperature is lowered due to the coupling between restricted guest dynamics and symmetry lowering of the host lattice.D etermining more general guidelines for the phase transition of clathrate hydrates at lower temperatures taking into account the analogy between clathrate hydrates and clathrasils will be the topic of future studies.F urthermore,t his work will provide an additional understanding for various host-guest compounds and their weak host-guest interactions besides clathrate hydrates and clathrasils.…”

Section: Methodsmentioning

confidence: 99%

Phase Transition of a Structure II Cubic Clathrate Hydrate to a Tetragonal Form

et al. 2016

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The crystal structure and phase transition of cubic structure II (sII) binary clathrate hydrates of methane (CH4 ) and propanol are reported from powder X-ray diffraction measurements. The deformation of host water cages at the cubic-tetragonal phase transition of 2-propanol+CH4 hydrate, but not 1-propanol+CH4 hydrate, was observed below about 110 K. It is shown that the deformation of the host water cages of 2-propanol+CH4 hydrate can be explained by the restriction of the motion of 2-propanol within the 5(12) 6(4) host water cages. This result provides a low-temperature structure due to a temperature-induced symmetry-lowering transition of clathrate hydrate. This is the first example of a cubic structure of the common clathrate hydrate families at a fixed composition.

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Section: Methodsmentioning

confidence: 99%

Phase Transition of a Structure II Cubic Clathrate Hydrate to a Tetragonal Form

et al. 2016

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“…The framework topology of DOH is identical to that of the hexagonal sH gas hydrate [15]. Dodecasil-3C (MTN) [7,31,32], also known as ZSM-39 [3], holdstite [33] or CF-4 [34], is another member of the dodecasil series and is constructed from ABC ABC stacking of the dodecasil layers. Dodecasil-3C is isotypic ] cage.…”

Section: Clathrasils Containing [5 12 ] Cagementioning

confidence: 99%

Clathrate compounds of silica

Momma

2014

J. Phys.: Condens. Matter

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A review on silica clathrate compounds, which are variants of pure silica zeolites with relatively small voids, is presented. Zeolites have found many uses in industrial and domestic settings as materials for catalysis, separations, adsorption, ion exchange, drug delivery, and other applications. Zeolites with pure silica frameworks have attracted particular interest because of their high thermal stability, well-characterized framework structures, and simple chemical compositions. Recent advances in new synthetic routes have extended the structural diversity of pure silica zeolite frameworks. Thermochemical analyses and computational simulations have provided a basis for applications of these materials and the syntheses of new types of pure silica zeolites. High-pressure and high-temperature experiments have also revealed diverse responses of these framework structures to pressure, temperature, and various guest species. This paper summarizes the framework topologies, synthetic processes, energetics, physical properties, and some applications of silica clathrate compounds.

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“…Finally, the above-described symmetry changes at the cubic/tetragonal phase transition in D3C-THF find their correspondence in the structural changes through the transition (9). The action of a one-dimensional local tilt system violates the symmetry of the 'para'-phase.…”

Section: Cubic/tetragonal Phase Transitionsmentioning

confidence: 89%