scholarly journals The Phase Transition of Calcium Sulfide Under High Pressure

2022 ◽  
Vol 2148 (1) ◽  
pp. 012015
Author(s):  
Huidong Feng ◽  
Shuai Wang ◽  
Baojia Wu

Abstract We carried out the accurate in situ angle derisive x-ray diffraction experiments and the electrical resistivity in CaS under high pressure. The result shows the pressure-induced phase transition of CaS from Na Cl-type structure (the space group Fm3m, phase I ) to Cs Cl-type structure (the space group Pm3m, phase II ) is reversible and the transition point is around 40.0 GPa; in the meantime, the electrical resistivity and light permeability decrease as the pressure increases and occur obvious discontinuities at the corresponding phase transition point; the result of the first-principles calculations is in concordance with the measurement results.

Author(s):  
Rebecca Scatena ◽  
Michał Andrzejewski ◽  
Roger D Johnson ◽  
Piero Macchi

Through in-situ, high-pressure x-ray diffraction experiments we have shown that the homoleptic perovskite-like coordination polymer [(CH3)2NH2]Cu(HCOO)3 undergoes a pressure-induced orbital reordering phase transition above 5.20 GPa. This transition is distinct...


2017 ◽  
Vol 102 (3) ◽  
pp. 666-673 ◽  
Author(s):  
Anna Pakhomova ◽  
Leyla Ismailova ◽  
Elena Bykova ◽  
Maxim Bykov ◽  
Tiziana Boffa Ballaran ◽  
...  

Author(s):  
Paolo Lotti ◽  
G. Diego Gatta ◽  
Marco Merlini ◽  
Hanns-Peter Liermann

AbstractThe high-pressure behavior of a synthetic mordenite-Na (space group:


2013 ◽  
Vol 705 ◽  
pp. 97-100
Author(s):  
Jia Wang ◽  
Gang Peng ◽  
Bao Jia Wu

Phase transition of CaB6 sample under high pressure was studied by in situ electrical conductivity measurements and synchrotron X-ray diffraction up to 26GPa. Three anomalies in conductivity change were found respectively at 3.7, 12.4 and 21.9GPa. X-ray diffraction reveals that CaB6 transforms from Pm3m to orthogonal structure at 12.32GPa and hence the abnormal conductivity change at 12.4GPa can be attributed to the structural phase transition. The other two anomalies were considered as pressure-induced electronic phase transition in the pressure range of our measurements.


RSC Advances ◽  
2019 ◽  
Vol 9 (33) ◽  
pp. 18954-18962 ◽  
Author(s):  
Jingjing Niu ◽  
Xiang Wu ◽  
Haibin Zhang ◽  
Shan Qin

In situ high-pressure experiments on La2Zr2O7 and La0.5Gd1.5Zr2O7 have been carried out at up to approximately 40 GPa using synchrotron X-ray diffraction and Raman spectroscopy combined with a diamond anvil cell technique.


1987 ◽  
Vol 42 (7) ◽  
pp. 818-824 ◽  
Author(s):  
Klaus Zimmermann ◽  
Gerhard Thiele

Abstract Cs3Tl2Br9, which has been synthesized either by heating a 3:2 mixture of CsBr/TlBr with bromine in a closed system or by reaction of these components in aqueous solutions, shows dimorphism. The phase transition (170 °C) was characterized by thermal analysis and X-ray diffraction. The low temperature modification α-Cs3TlBr9 crystallizes in the monoclinic space group P21/m (a = 964.98(9), b = 779.49(7), c = 1382.16(13) pm, β = 92.68(1)°, Z = 2). The structure is built up from TlBr6 octahedra linked by sharing vertices to chains and isolated TlBr4 tetrahedra. The high tem perature modification β-Cs3Tl2Br9 represents the undistorted trigonal Cs3Bi2Br9-type structure (a = 796.80(8), c - 982.98(15) pm).


Author(s):  
Kun Li ◽  
Junjie Wang ◽  
Vladislav A. Blatov ◽  
Yutong Gong ◽  
Naoto Umezawa ◽  
...  

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.


Author(s):  
Gunter Heymann ◽  
Elisabeth Selb ◽  
Toni Buttlar ◽  
Oliver Janka ◽  
Martina Tribus ◽  
...  

By high-pressure/high-temperature multianvil synthesis a new high-pressure (HP) phase of Co3TeO6 was obtained. The compound crystallizes in the acentric trigonal crystal system of the Ni3TeO6-type structure with space group R3...


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