Vibrational Spectra of SiH4 and SiD4–SiH4 Mixtures in the Condensed States

1972 ◽  
Vol 50 (1) ◽  
pp. 35-42 ◽  
Author(s):  
R. P. Fournier ◽  
R. Savoie ◽  
Nguyen Dinh The ◽  
R. Belzile ◽  
A. Cabana
Keyword(s):  
Phase Transition ◽  
Low Temperature ◽  
Phase I ◽  
Raman Spectra ◽  
Vibrational Spectra ◽  
Crystalline Phase ◽  
Solid Phase ◽  
Transition Phase ◽  
Solid Phase Transition

The i.r. and Raman spectra of liquid and crystalline SiH4 and SiD4–SiH4 mixtures have been recorded. The spectra show striking changes when the crystal undergoes the solid–solid phase transition. Phase I is disordered. Possible site, and factor groups for the low temperature crystalline phase are proposed.

Vibrational Spectra of N2H5HC2O4 and N2D5DC2O4

1975 ◽  
Vol 53 (9) ◽  
pp. 1387-1392 ◽  
Author(s):  
R. Savoie ◽  
M. Guay
Keyword(s):  
Phase Transition ◽  
High Temperature ◽  
Low Temperature ◽  
Crystal Structures ◽  
Raman Spectra ◽  
Vibrational Spectra ◽  
Unit Cell ◽  
Infrared And Raman Spectra ◽  
Solid Phases ◽  
High Temperature Modification

Infrared and Raman spectra of N2H5HC2O4 and N2D5DC2O4 have been recorded at various temperatures between 77 and 300 K. The results at 300 K are consistent with the known crystal structures of these solids. A phase transition has been detected at ∼ 240 K in N2D5DC2O4 and although there are similarities between the two stable solid phases of this compound, the low-temperature form appears to be centrosymmetric and to have a larger unit cell than the high-temperature modification.

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.

Solid–solid phase transition study of ε-CL-20/binder composites

RSC Advances ◽  
2016 ◽  
Vol 6 (2) ◽  
pp. 859-865 ◽  
Author(s):  
Changping Guo ◽  
Dunju Wang ◽  
Bing Gao ◽  
Jun Wang ◽  
Bo Luo ◽  
...  
Keyword(s):  
Phase Transition ◽  
Solid Phase ◽  
Solid Phase Transition ◽  
Transition Study ◽  
Dsc Curves

The comparison of solid–solid phase transition (ε → γ polymorph) of CL-20 and Cl-20/composites revealed by DSC curves.

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