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Melting curve and phase diagram of ammonia monohydrate at high pressure and temperature
Melting curve and phase diagram of ammonia monohydrate at high pressure and temperature
- Source :
- Journal of Chemical Physics, Journal of Chemical Physics, 2020, 153 (15), pp.154503. ⟨10.1063/5.0021207⟩, Journal of Chemical Physics, American Institute of Physics, 2020, 153 (15), pp.154503. ⟨10.1063/5.0021207⟩
- Publication Year :
- 2020
- Publisher :
- HAL CCSD, 2020.
-
Abstract
- International audience; The phase diagram and melting behavior of the equimolar water-ammonia mixture have been investigated by Raman spectroscopy, x-ray diffraction, and visual observations from 295 K to 675 K and up to 9 GPa. Our results show non-congruent melting behavior of ammonia monohydrate (AMH) solid below 324 K and congruent melting at higher temperatures. The congruent melting is associated with the stability of a previously unobserved solid phase of AMH, which we named AMH-VII. Another, presumably water-rich, hydrate has also been detected in the range 4 GPa-7 GPa at 295 K on decompression of the high pressure disordered ionico-molecular alloy (DIMA) phase. Comparing our melting data to the literature suggests that non-congruent melting extends from 220 K to 324 K and that the solid phase that borders the fluid between 220 K and 270 K, called AMH-III, is not a proper phase of AMH but a solid solution of ammonia hemihydrate and ice. These results allow us to propose a revised and extended experimental phase diagram of AMH. Published under license by AIP Publishing. https://doi.org/10.1063/5.0021207 ., s
- Subjects :
- Materials science
Alloy
General Physics and Astronomy
Thermodynamics
02 engineering and technology
engineering.material
021001 nanoscience & nanotechnology
01 natural sciences
Melting curve analysis
symbols.namesake
Congruent melting
Phase (matter)
0103 physical sciences
engineering
symbols
Physical and Theoretical Chemistry
[PHYS.COND]Physics [physics]/Condensed Matter [cond-mat]
010306 general physics
0210 nano-technology
Hydrate
Raman spectroscopy
Solid solution
Phase diagram
Subjects
Details
- Language :
- English
- ISSN :
- 00219606 and 10897690
- Database :
- OpenAIRE
- Journal :
- Journal of Chemical Physics, Journal of Chemical Physics, 2020, 153 (15), pp.154503. ⟨10.1063/5.0021207⟩, Journal of Chemical Physics, American Institute of Physics, 2020, 153 (15), pp.154503. ⟨10.1063/5.0021207⟩
- Accession number :
- edsair.doi.dedup.....b995183fa806cbce5d82fa07f636f68e
- Full Text :
- https://doi.org/10.1063/5.0021207⟩