Rights statement: Copyright 2020 American Institute of Physics. The following article appeared in The Journal of Chemical Physics, 152 (14), 2020 and may be found at http://dx.doi.org/10.1063/5.0003224 This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics.
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Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Solid-solid phase equilibria in the NaCl-KCl system
AU - Anwar, J.
AU - Leitold, C.
AU - Peters, B.
N1 - Copyright 2020 American Institute of Physics. The following article appeared in The Journal of Chemical Physics, 152 (14), 2020 and may be found at http://dx.doi.org/10.1063/5.0003224 This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics.
PY - 2020/4/14
Y1 - 2020/4/14
N2 - Solid solutions, structurally ordered but compositionally disordered mixtures, can form for salts, metals, and even organic compounds. The NaCl-KCl system forms a solid solution at all compositions between 657 °C and 505 °C. Below a critical temperature of 505 °C, the system exhibits a miscibility gap with coexisting Na-rich and K-rich rocksalt phases. We calculate the phase diagram in this region using the semi-grand canonical Widom method, which averages over virtual particle transmutations. We verify our results by comparison with free energies calculated from thermodynamic integration and extrapolate the location of the critical point. Our calculations reproduce the experimental phase diagram remarkably well and illustrate how solid-solid equilibria and chemical potentials, including those at metastable conditions, can be computed for materials that form solid solutions.
AB - Solid solutions, structurally ordered but compositionally disordered mixtures, can form for salts, metals, and even organic compounds. The NaCl-KCl system forms a solid solution at all compositions between 657 °C and 505 °C. Below a critical temperature of 505 °C, the system exhibits a miscibility gap with coexisting Na-rich and K-rich rocksalt phases. We calculate the phase diagram in this region using the semi-grand canonical Widom method, which averages over virtual particle transmutations. We verify our results by comparison with free energies calculated from thermodynamic integration and extrapolate the location of the critical point. Our calculations reproduce the experimental phase diagram remarkably well and illustrate how solid-solid equilibria and chemical potentials, including those at metastable conditions, can be computed for materials that form solid solutions.
KW - Phase diagrams
KW - Phase equilibria
KW - Potassium compounds
KW - Sodium chloride
KW - Critical temperatures
KW - Grand canonical
KW - Meta-stable condition
KW - Miscibility gap
KW - Solid-solid
KW - Thermodynamic integration
KW - Virtual particles
KW - Widom methods
KW - Solid solutions
U2 - 10.1063/5.0003224
DO - 10.1063/5.0003224
M3 - Journal article
VL - 152
JO - Journal of Chemical Physics
JF - Journal of Chemical Physics
SN - 0021-9606
IS - 14
M1 - 144109
ER -