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Absolute entropy of a condensed phase (crystal, liquid, glass, ...) in equilibrium with its vapor, as a function of temperature T and in units of kJ/mol. All entropies and enthalpies are derived through integration of the associated heat capacities at saturation. Integration constants at phase transition temperatures are included as equation constants.
Please note that the equations below are expressed in terms of heat capacity and not in the necessary integral form.
csat = b/τ + ∑(aiTi), i ∈ [0, nterms - 2]
c = ∑aiTi, i ∈ [0, nterms - 1]
where τ = 1 - T/Tc
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The TRC Group is part of the Thermophysical Properties Division in NIST's Material Measurement Laboratory
The National Institute of Standards and Technology is an agency of the U.S. Department of Commerce