Realizing Predicted Crystal Structures at Extreme Conditions:  The Low-Temperature and High-Pressure Crystal Structures of 2-Chlorophenol and 4-Fluorophenol

2005 ◽  
Vol 5 (3) ◽  
pp. 1055-1071 ◽  
Author(s):  
Iain D. H. Oswald ◽  
David R. Allan ◽  
Graeme M. Day ◽  
W. D. Samuel Motherwell ◽  
Simon Parsons
Keyword(s):  
High Pressure ◽  
Low Temperature ◽  
Crystal Structures ◽  
Extreme Conditions

Low Temperature (4K) and High Pressure (6.5 Kbars) Crystal Structures of (TMTSF)2PF6

1985 ◽  
Vol 119 (1) ◽  
pp. 225-232 ◽  
Author(s):  
Bernard Galiois ◽  
Jacques Gaultier ◽  
Christian Hauw ◽  
Daniel Chasseau ◽  
Alain Meresse ◽  
...  
Keyword(s):  
High Pressure ◽  
Low Temperature ◽  
Crystal Structures

scholarly journals Superconductivity in Materials under Extreme Conditions: An ab-initio Prediction from Density Functional Theory

2021 ◽  
Author(s):  
Thiti Bovornratanaraks ◽  
Prutthipong Tsuppayakorn-aek
Keyword(s):  
Density Functional Theory ◽  
High Pressure ◽  
Ab Initio ◽  
Crystal Structures ◽  
Density Functional ◽  
Ambient Pressure ◽  
Extreme Conditions ◽  
Functional Theory ◽  
Novel Structure ◽  
And Performance

The relation between thermodynamically stable and electronic structure preparation is one of the fundamental questions in physics, geophysics and chemistry. Since the discovery of the novel structure, this has remained as one of the main questions regarding the very foundation of elemental metals. Needless to say this has also bearings on extreme conditions physics, where again the relation between structure and performance is of direct interest. Crystal structures have been mainly at ambient conditions, i.e. at room temperature and ambient pressure. Nevertheless it was realized early that there is also a fundamental relation between volume and structure, and that this dependence could be most fruitfully studied by means of high pressure experimental techniques. From a theoretical point of view this is an ideal type of experiment, since only the volume is changed, which is a very clean variation of the external conditions. Therefore, at least in principle, the theoretical approach remains the same irrespective of the high pressure loading of the experimental sample. Theoretical modeling is needed to explain the measured data on the pressure volume relationships in crystal structures. Among those physical properties manifested itself under high pressure, superconductivity has emerged as a prominent property affected by pressure. Several candidate structure of materials are explored by ab initio random structure searching (AIRSS). This has been carried out in combination with density functional theory (DFT). The remarkable solution of AIRSS is possible to expect a superconductivity under high pressure. This chapter provide a systematically review of the structural prediction and superconductivity in elemental metals, i.e. lithium, strontium, scandium, arsenic.

scholarly journals The high-pressure and low-temperature structural behaviour of 2,2,2-trifluoroethanol

CrystEngComm ◽  
2019 ◽  
Vol 21 (30) ◽  
pp. 4501-4506
Author(s):  
S. A. Barnett ◽  
D. R. Allan
Keyword(s):  
High Pressure ◽  
Low Temperature ◽  
Crystal Structures ◽  
Structural Behaviour

Polymorphic crystal structures have been determined for 2,2,2-trifluoroethanol by using the in situ crystallography techniques of high pressure and cryo-cooling.

scholarly journals The low-temperature and high-pressure crystal structures of cyclobutanol (C4H7OH)

2005 ◽  
Vol 61 (4) ◽  
pp. 449-454 ◽  
Author(s):  
Pamela A. McGregor ◽  
David R. Allan ◽  
Simon Parsons ◽  
Colin R. Pulham
Keyword(s):  
High Pressure ◽  
Low Temperature ◽  
Crystal Structures ◽  
X Ray Diffraction ◽  
Structural Behaviour ◽  
Coordination Environment ◽  
X Ray ◽  
Alkyl Groups ◽  
Graph Set ◽  
Packing Arrangement

The low-temperature and high-pressure crystal structures of cyclobutanol (C4H7OH) have been determined using single-crystal X-ray diffraction techniques. At temperatures below 220 K, cyclobutanol crystallizes in the Aba2 space group (Z′ =  2) and its crystal structure is composed of pseudo-threefold hydrogen-bonded molecular catemers [assigned as C_2^2(4) in graph-set notation], which lie parallel to the crystallographic a axis. At a pressure of 1.3 GPa, the crystal symmetry changes to Pna21 (Z′  =  1) and the molecular catemers [expressed as C(2) in graph-set notation] adopt a pseudo-twofold arrangement. This structural behaviour is in agreement with our previous observations for phenol and its halogenated derivatives 2-chlorophenol and 4-fluorophenol, where pressure was found to favour a molecular packing more closely associated with small alkyl groups rather than that of relatively bulky alkyl groups. In addition, an examination of the molecular coordination environment in the low-temperature and high-pressure structures of cyclobutanol reveals that the change in structure on application of pressure appears to be driven by the molecules assuming a packing arrangement which more closely resembles that adopted in hard-sphere structures.

High pressure and very low temperature effects on the crystal structures of some iron(II) complexes

2001 ◽  
Vol 4 (2) ◽  
pp. 161-171 ◽  
Author(s):  
Philippe Guionneau ◽  
Catherine Brigouleix ◽  
Yvette Barrans ◽  
Andrés E Goeta ◽  
Jean-François Létard ◽  
...  
Keyword(s):  
High Pressure ◽  
Low Temperature ◽  
Crystal Structures ◽  
Temperature Effects ◽  
Very Low Temperature

scholarly journals Phase transitions and chemical reactions of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine under high pressure and high temperature

RSC Advances ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 5825-5833 ◽  
Author(s):  
Dexiang Gao ◽  
Jin Huang ◽  
Xiaohuan Lin ◽  
Dongliang Yang ◽  
Yajie Wang ◽  
...  
Keyword(s):  
High Pressure ◽  
Phase Transitions ◽  
High Temperature ◽  
Crystal Structures ◽  
Chemical Reactions ◽  
Extreme Conditions

Phase transitions, crystal structures and chemical reactions of β-HMX under extreme conditions were described systematically.

scholarly journals Über die Struktur und das Hochdruckverhalten des β-Li6UO6.

1976 ◽  
Vol 31 (8) ◽  
pp. 1053-1057 ◽  
Author(s):  
Jürgen Hauck ◽  
Matthias Rosenhauer
Keyword(s):  
Solid Solution ◽  
High Pressure ◽  
Phase Transformation ◽  
Low Temperature ◽  
Crystal Structures ◽  
Infrared Spectra ◽  
Invariant Point ◽  
Close Relationship ◽  
Triclinic Unit Cell ◽  
Reversible Phase

Li6UO6 has a reversible phase transformation at 680°C and decomposes above about 850°C. At high pressure the low temperature modification becomes unstable because of an invariant point in the system Li2O—Li4UO5 at approximately 13 Kb and 620°C. β-Li6UO6 has a triclinic unit cell with a = 5.203, b= 5.520, c = 5.536 Å, α = 114.7, β = 120.7 and γ = 75.5°. The close relationship between the crystal structures of Li6TeO6 and Li6UO6 is also suggested from similar infrared spectra and from partial solid solution Li6UO6—Li6TeO6.

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