A tetragonal polymorph of SrMn2P2made under high pressure – theory and experiment in harmony

A trigonal–tetragonal phase transition in SrMn2P2is proposed and confirmed experimentally under high pressure. At ambient pressure, SrMn2P2crystallizes in the primitive trigonal La2O3structure type (space groupP3̄m1) in blue. Under high pressure, the tetragonal ThCr2Si2structure type (space groupI4/mmm) in red is more stable.

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A high-pressure cubic-to-tetragonal phase-transition in melanophlogite, a SiO2 clathrate phase

Microporous and Mesoporous Materials ◽

10.1016/j.micromeso.2009.10.004 ◽

2010 ◽

Vol 129 (1-2) ◽

pp. 267-273 ◽

Cited By ~ 11

Author(s):

Mario Tribaudino ◽

G. Diego Gatta ◽

Yongjae Lee

Keyword(s):

Phase Transition ◽

High Pressure ◽

Tetragonal Phase ◽

Tetragonal Phase Transition

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

Acta Crystallographica Section B Structural Science ◽

10.1107/s010876819600972x ◽

1997 ◽

Vol 53 (1) ◽

pp. 18-24 ◽

Cited By ~ 12

Author(s):

K. Knorr ◽

W. Depmeier

Keyword(s):

Phase Transition ◽

Tetragonal Phase ◽

Room Temperature ◽

Group Symmetry ◽

Ambient Conditions ◽

Space Group ◽

Symmetry Properties ◽

Ideal Framework ◽

Tetragonal Phase Transition ◽

The Ideal

The structure of dodecasil 3C-tetrahydrofuran [Si68O136]·4M, M = (CH2)4O, at room temperature was determined from a merohedrally twinned crystal in the tetragonal space group I41/a. The deformation of the ideal framework at the cubic tetragonal phase transition at T c ≃ 365 K could be explained mainly by two different symmetry-breaking processes. (i) A tetragonal tetrahedron distortion of the Si(5) tetrahedra and (ii) a hitherto unknown local one-dimensional tilt mechanism, localized in the tetrahedral network. The location of the axes of this tilt system coincides with the positions of the fourfold inversion axes in the space group I41/a. At room temperature the tilt angle is = 24°. The symmetry properties of the tilt system can explain the reduction of space-group symmetry from the space group of the ideal structure Fd\overline 3m to the space group at ambient conditions I41/a. The guest molecule tetrahydrofuran does not fit the cage symmetry and has been found to be dynamically disordered. The average structure shows an off-center location in the [51264] cage and follows the local \overline 4symmetry of the cage.

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Variable temperature and high-pressure crystal chemistry of perovskite formamidinium lead iodide: a single crystal X-ray diffraction and computational study

Chemical Communications ◽

10.1039/c7cc00995j ◽

2017 ◽

Vol 53 (54) ◽

pp. 7537-7540 ◽

Cited By ~ 22

Author(s):

Shijing Sun ◽

Zeyu Deng ◽

Yue Wu ◽

Fengxia Wei ◽

Furkan Halis Isikgor ◽

...

Keyword(s):

Phase Transition ◽

High Pressure ◽

Low Temperature ◽

Tetragonal Phase ◽

Computational Study ◽

Variable Temperature ◽

X Ray Diffraction ◽

Lead Iodide ◽

X Ray ◽

Tetragonal Phase Transition

Single crystals of [(NH2)2CH]PbI3 undergo a cubic-to-tetragonal phase transition at low temperature and high pressure.

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Orthorhombic to tetragonal phase transition in high TCsuperconductor YBa2Cu3O7-yand NdBa2Cu3O7-zunder high pressure

High Pressure Research ◽

10.1080/08957959008246142 ◽

1990 ◽

Vol 4 (1-6) ◽

pp. 420-422

Author(s):

H. Takahashi ◽

N. Mori ◽

Y. Miyane ◽

H. Kaneko ◽

J. Susaki ◽

...

Keyword(s):

Phase Transition ◽

High Pressure ◽

Tetragonal Phase ◽

Tetragonal Phase Transition

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First-principles studies of phase transition and structural stability of SrC2 under pressure

Modern Physics Letters B ◽

10.1142/s0217984914501905 ◽

2014 ◽

Vol 28 (24) ◽

pp. 1450190 ◽

Cited By ~ 3

Author(s):

Yi-Lin Lu ◽

Hui Zhao

Keyword(s):

Phase Transition ◽

High Pressure ◽

First Principles ◽

Phonon Dispersion ◽

Covalent Bond ◽

Text Structure ◽

High Pressure Phase ◽

Space Group ◽

Type Space ◽

Pressure Phase

Pressure-induced phase transitions in SrC 2 are investigated using the first-principles plane wave pseudopotential method within the generalized gradient approximation. The phase transition from monoclinic phase ( CaC 2-II-type, space group C2/c) to trigonal ( CaC 2-VII-type, space group [Formula: see text]) structure is predicted to occur at 10.4 GPa. The high-pressure phase is thermodynamic, mechanically and dynamically stable, as verified by the calculations of its formation energy, elastic stiffness constants and phonon dispersion. Further the electronic analysis predicates this high-pressure phase to be an insulator. When increasing pressure, the ionic bond between C and Sr is strengthened, as well is the covalent bond between C and C , however, the increase of the ionic interaction between Sr and C preponderates over that of the covalent bond interaction, so the gap is narrowed.

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Crystal and electronic structure engineering of tin monoxide by external pressure

Journal of Advanced Ceramics ◽

10.1007/s40145-021-0458-1 ◽

2021 ◽

Author(s):

Kun Li ◽

Junjie Wang ◽

Vladislav A. Blatov ◽

Yutong Gong ◽

Naoto Umezawa ◽

...

Keyword(s):

Phase Transition ◽

High Pressure ◽

Band Gap ◽

High Pressures ◽

Low Pressure ◽

Widespread Application ◽

Space Group ◽

Tin Monoxide ◽

High Possibility ◽

Pressure Phase

AbstractAlthough tin monoxide (SnO) is an interesting compound due to its p-type conductivity, a widespread application of SnO has been limited by its narrow band gap of 0.7 eV. In this work, we theoretically investigate the structural and electronic properties of several SnO phases under high pressures through employing van der Waals (vdW) functionals. Our calculations reveal that a metastable SnO (β-SnO), which possesses space group P21/c and a wide band gap of 1.9 eV, is more stable than α-SnO at pressures higher than 80 GPa. Moreover, a stable (space group P2/c) and a metastable (space group Pnma) phases of SnO appear at pressures higher than 120 GPa. Energy and topological analyses show that P2/c-SnO has a high possibility to directly transform to β-SnO at around 120 GPa. Our work also reveals that β-SnO is a necessary intermediate state between high-pressure phase Pnma-SnO and low-pressure phase α-SnO for the phase transition path Pnma-SnO →β-SnO → α-SnO. Two phase transition analyses indicate that there is a high possibility to synthesize β-SnO under high-pressure conditions and have it remain stable under normal pressure. Finally, our study reveals that the conductive property of β-SnO can be engineered in a low-pressure range (0–9 GPa) through a semiconductor-to-metal transition, while maintaining transparency in the visible light range.

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