scholarly journals Melting Curve Anomaly and Solid-Solid Phase Transition at High Pressures

1972 ◽  
Vol 47 (4) ◽  
pp. 1069-1086 ◽  
Author(s):  
Yoshiki Kuramoto ◽  
Hiroshi Furukawa
Keyword(s):  
Phase Transition ◽  
High Pressures ◽  
Solid Phase ◽  
Melting Curve ◽  
Solid Phase Transition

n-pentanol at high pressures: Rotational isomerism in the liquid phase and the liquid-solid phase transition

2006 ◽  
Vol 124 (4) ◽  
pp. 044508 ◽  
Author(s):  
V. G. Baonza ◽  
M. Taravillo ◽  
A. Cazorla ◽  
S. Casado ◽  
M. Cáceres
Keyword(s):  
Phase Transition ◽  
Liquid Phase ◽  
High Pressures ◽  
Solid Phase ◽  
Rotational Isomerism ◽  
Solid Phase Transition

scholarly journals Low Temperature and High-Pressure Study of Bending L-Leucinium Hydrogen Maleate Crystals

Crystals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1575
Author(s):  
Kseniya D. Skakunova ◽  
Denis A. Rychkov
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Low Temperatures ◽  
High Pressures ◽  
Solid Phase ◽  
Extreme Conditions ◽  
Pressure Impact ◽  
Solid Phase Transition ◽  
High Pressure Study ◽  
Crystal Fracture

The polymorphism of molecular crystals is a well-known phenomenon, resulting in modifications of physicochemical properties of solid phases. Low temperatures and high pressures are widely used to find phase transitions and quench new solid forms. In this study, L-Leucinium hydrogen maleate (LLHM), the first molecular crystal that preserves its anomalous plasticity at cryogenic temperatures, is studied at extreme conditions using Raman spectroscopy and optical microscopy. LLHM was cooled down to 11 K without any phase transition, while high pressure impact leads to perceptible changes in crystal structure in the interval of 0.0–1.35 GPa using pentane-isopentane media. Surprisingly, pressure transmitting media (PTM) play a significant role in the behavior of the LLHM system at extreme conditions—we did not find any phase change up to 3.05 GPa using paraffin as PTM. A phase transition of LLHM to amorphous form or solid–solid phase transition(s) that results in crystal fracture is reported at high pressures. LLHM stability at low temperatures suggests an alluring idea to prove LLHM preserves plasticity below 77 K.

Solidification of Ionic Liquids: Theory and Techniques

2010 ◽  
Vol 63 (4) ◽  
pp. 544 ◽  
Author(s):  
Anja-Verena Mudring
Keyword(s):  
Phase Transition ◽  
Ionic Liquid ◽  
Ionic Liquids ◽  
Solid Phase ◽  
Soft Materials ◽  
Separation Science ◽  
Vast Number ◽  
Plastic Crystals ◽  
Thermal Fluids ◽  
Solid Phase Transition

Ionic liquids (ILs) have become an important class of solvents and soft materials over the past decades. Despite being salts built by discrete cations and anions, many of them are liquid at room temperature and below. They have been used in a wide variety of applications such as electrochemistry, separation science, chemical synthesis and catalysis, for breaking azeotropes, as thermal fluids, lubricants and additives, for gas storage, for cellulose processing, and photovoltaics. It has been realized that the true advantage of ILs is their modular character. Each specific cation–anion combination is characterized by a unique, characteristic set of chemical and physical properties. Although ILs have been known for roughly a century, they are still a novel class of compounds to exploit due to the vast number of possible ion combinations and one fundamental question remains still inadequately answered: why do certain salts like ILs have such a low melting point and do not crystallize readily? This Review aims to give an insight into the liquid–solid phase transition of ILs from the viewpoint of a solid-state chemist and hopes to contribute to a better understanding of this intriguing class of compounds. It will introduce the fundamental theories of liquid–solid-phase transition and crystallization from melt and solution. Aside form the formation of ideal crystals the development of solid phases with disorder and of lower order like plastic crystals and liquid crystals by ionic liquid compounds are addressed. The formation of ionic liquid glasses is discussed and finally practical techniques, strategies and methods for crystallization of ionic liquids are given.

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