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We report experimental constraints on the melting curve of potassium chloride (KCl) between 3.2 and 9 GPa from in situ ionic conduction measurements using a multi-anvil apparatus. On the basis of concurrent measurements of KCl and sodium chloride (NaCl) at 1 bar using the differential thermal analysis (DTA) method and Pt sphere marker, we show that the peak rate of increase in ionic current with temperature upon heating coincides with latent heat ledge and fall of Pt sphere, thus establishing the criterion for melting detection from ionic conduction measurements. Applying this criterion to high pressures, we found that the melting point of KCl rose steeply with increasing pressure to exceed 2443 ± 100 K at 9 GPa. Fitting the results of this study together with existing data at pressures below 4 GPa and above 20 GPa, we obtained the Simon’s melting equation for KCl in the simple cubic B2 structure between 1.8 and 50 GPa: T m = 1323 ( P − 1.87 2.2 ( 1 ) + 1 ) 1 2.7 ( 1 ) , where T is in K and P is in GPa. Starting at 1 bar, the melting point of KCl increases at an average rate of ~150 K/GPa to cross that of Pt near 9 GPa. The highly refractory nature of KCl makes it a sensitive pressure calibrant for the large-volume pressure at moderate pressures and a potential sample container for experiments at moderate pressures and very high temperatures.
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This content will become publicly available on October 1, 2026
High pressure suppresses the laser-induced nucleation of supersaturated aqueous potassium chloride solutions
We report the suppression of nucleation in the nonphotochemical laser-induced nucleation of supersaturated aqueous potassium chloride solutions when the system pressure is above ambient pressure. The crystal yield at 51.7 bar is reduced to 5% of its value at 1 bar, and the crystal number dependence on pressure fits well to a semiempirical model based on the impurity-heating mechanism and the adiabatic compression of an ideal gas nanobubble. Our results complement recent findings by Barber and Alexander [] using high-speed imaging of bubbles preceding the observation of cesium chloride crystals. Together, these two studies provide compelling evidence for the impurity-heating mechanism.
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- PAR ID:
- 10645212
- Publisher / Repository:
- Physical Review Journals
- Date Published:
- Journal Name:
- Physical Review Research
- Volume:
- 7
- Issue:
- 4
- ISSN:
- 2643-1564
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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