Solid-solution aqueous-solution equilibria: Thermodynamic theory and representation

American Journal of Science
By:  and 



Thorstenson and Plummer's (1977) "stoichiometric saturation' model is reviewed, and a general relation between stoichiometric saturation Kss constants and excess free energies of mixing is derived for a binary solid-solution B1-xCxA: GE = RT[ln Kss - xln(xKCA) - (l-x)ln((l-x)KBA)]. This equation allows a suitable excess free energy function, such as Guggenheim's (1937) sub-regular function, to be fitted from experimentally determined Kss constants. Solid-phase free energies and component activity-coefficients can then be determined from one or two fitted parameters and from the endmember solubility products KBA and KCA. A general form of Lippmann's (1977,1980) "solutus equation is derived from an examination of Lippmann's (1977,1980) "total solubility product' model. Lippmann's II or "total solubility product' variable is used to represent graphically not only thermodynamic equilibrium states and primary saturation states but also stoichiometric saturation and pure phase saturation states.

Publication type Article
Publication Subtype Journal Article
Title Solid-solution aqueous-solution equilibria: Thermodynamic theory and representation
Series title American Journal of Science
DOI 10.2475/ajs.290.2.164
Volume 290
Issue 2
Year Published 1990
Language English
Publisher American Journal of Science
Contributing office(s) Toxic Substances Hydrology Program
Description 38 p.
First page 164
Last page 201
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