Thermodynamic model of the system H+-NH4 +-Na+-SO4 2-NO3 --Cl--H2O at 298.15 K

Simon L. Clegg, Peter Brimblecombe, Anthony S. Wexler

Research output: Contribution to journalArticlepeer-review

422 Scopus citations


A multicomponent mole-fraction-based thermodynamic model of the H+-NH4 +Na+-SO4 2--NO3 --Cl--H2O system is used to represent aqueous-phase activities, equilibrium partial pressures (of H2O, HNO3, HCl, and NH3). and saturation with respect to 19 solid phases (NH4)2SO4(cr) (NH4)3H(SO4)2(cr), NH4HSO4(cr), NH4-NO3(cr) NH4Cl4(cr), Na2SO4·10H2O(cr), Na2SO4(cr), Na3H(SO4)2(cr), NaHSO4·H2O(cr), NaHSO4(cr), NaH3-(SO4)2·H2O (cr), NaNO3(cr), NaCl(cr), NH4HSO4·NH4NO3(cr), (NH4)2SO4·2NH4NO 3(cr), (NH4)2SO4·3NH4NO 3(cr), (NH4)2SO4·Na2SO 4·4H2O(cr), Na2SO4·NaNO3·H2O (cr), 2NaNO3·NH4NO3(cr)). The model is valid for concentrations from infinite dilution 10 saturation (with respect to the solid phases) and to about 40 mol kg-1 for acid sulfate systems which can remain liquid to concentrations approaching the pure acid. Parameters for H2-SO4-H2O interactions were adopted from a previous study, and values for other binary (water-electrolyte) and ternary (water and three ions) interactions were determined from extensive literature data for salt solubilities, electromotive forces, osmotic coefficients, and vapor pressures. The model is compared with solubility measurements for the quaternary ion systems H+-Na+-SO4 2--Cl--H 2O and NH4 +-Na+-SO4 2--Cl --H2O.

Original languageEnglish (US)
Pages (from-to)2155-2171
Number of pages17
JournalJournal of Physical Chemistry A
Issue number12
StatePublished - Mar 19 1998
Externally publishedYes

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry


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