Prediction of the thermodynamic properties of aqueous metal complexes to 1000{degrees}C and 5n kb

Journal Article · Tue Apr 01 04:00:00 EST 1997 · Geochimica et Cosmochimica Acta

DOI:https://doi.org/10.1016/S0016-7037(97)00009-4· OSTI ID:543161

Sverjensky, D A ^[1]; Shock, E L ^[2]; Helgeson, H C ^[3]

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1. Johns Hopkins Univ., Baltimore, MD (United States)
2. Washington Univ., St. Louis, MO (United States)
3. Univ. of California, Berkeley, CA (United States)

A large number of aqueous metal complexes contribute significantly to hydrothermal, metamorphic, and magmatic processes in the crust of the Earth. Nevertheless, relatively few thermodynamic data other than dissociation constants (K) for a few dozen of these complexes have been determined experimentally at elevated temperatures and pressures. The calculations summarized below are intended to supplement these experimental data by providing interim predictions of the thermodynamic properties of supercritical aqueous metal complexes using the revised HKF equations of state for aqueous species and correlations among equations of state parameters and standard partial molal properties at 25{degrees}C and 1 bar. These equations and correlations permit retrieval of the conventional standard partial molal entropies (S{sup 0}), volumes (V{sup 0}), and heat capacities (C{sub p}{sup 0}) of aqueous P metal complexes at 25{degrees}C and 1 bar from published values of log K in the supercritical region and the limited number of experimental dissociation constants available in the literature over relatively short ranges of elevated temperature at PSIT (PSAT and SAT are used in the present communication to refer to pressures corresponding to liquid-vapor equilibrium for the system H{sub 2}O, except at temperatures <100{degrees}C, where they refer to the reference pressure of 1 bar). The standard partial molal properties computed in this way can then be used to generate corresponding values of {Delta}S{sup 0}, {Delta}V{sup 0}, and {Delta}C{sub p}{sup 0} of association, which for similar complexes correlate linearly with S{sup 0}, V{sup 0}, and C{sub p}{sup 0}, respectively, of the constituent cations and ligands at 25{degrees}C and 1 bar. 200 refs., 28 figs., 19 tabs.

• OSTI ID: 543161
• Journal Information: Geochimica et Cosmochimica Acta, Journal Name: Geochimica et Cosmochimica Acta Journal Issue: 7 Vol. 61; ISSN GCACAK; ISSN 0016-7037
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
66 PHYSICS
GEOCHEMISTRY
HYDROTHERMAL SYSTEMS
MAGMATISM
METAMORPHISM
THERMODYNAMICS