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Updated: Jul 31, 2026
05:46
High-pressure Sapphire Cell for Phase Equilibria Measurements of CO2/Organic/Water Systems
Published on: January 24, 2014
Water-carbon dioxide solid phase equilibria at pressures above 4 GPa
E H Abramson1, O Bollengier2, J M Brown2
1Department of Earth and Space Sciences, University of Washington, Seattle, WA, 98195-1310, USA. evan@ess.washington.edu.
Scientific Reports
|April 13, 2017
Summary
Researchers observed carbonic acid, a solid phase in water-carbon dioxide mixtures, using a diamond-anvil cell. Its melting and peritectic curves were measured at high pressures and temperatures.
Area of Science:
- Geochemistry
- Materials Science
- Physical Chemistry
Background:
- The solid phase in the water-carbon dioxide system, previously identified as carbonic acid, has been studied under high-pressure conditions.
- Understanding phase behavior in mixed volatile systems is crucial for planetary science and geochemistry.
Purpose of the Study:
- To investigate the high-pressure phase behavior of carbonic acid in the mixed water-carbon dioxide system.
- To determine the melting and peritectic curves of carbonic acid.
- To characterize the crystal structure and spectroscopic properties of high-pressure carbonic acid.
Main Methods:
- High-pressure experiments using a diamond-anvil cell.
- In-situ observation of phase transitions.
- Single-crystal X-ray diffraction for structural analysis.
- Raman spectroscopy for vibrational characterization.
Main Results:
- The existence of a solid carbonic acid phase was confirmed in a diamond-anvil cell.
- Pressure-temperature paths for melting and peritectic curves were measured, starting from a quadruple point at 4.4 GPa and 165°C.
- Single-crystal X-ray diffraction revealed a triclinic crystal structure with specific unit cell parameters at 6.5 GPa and 20°C.
- Raman spectra showed a major line around 1080 cm⁻¹ and lattice modes below 300 cm⁻¹.
Conclusions:
- This study provides critical data on the high-pressure phase diagram of the water-carbon dioxide system.
- The characterized carbonic acid phase has implications for understanding the interiors of icy planets and carbon cycling.
- The findings contribute to the fundamental knowledge of solid-fluid equilibria under extreme conditions.
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