Original Article

Environmental Earth Sciences

, Volume 62, Issue 8, pp 1673-1683

First online:

Arsenic Eh–pH diagrams at 25°C and 1 bar

  • Peng LuAffiliated withDepartment of Geological Sciences, Indiana University
  • , Chen ZhuAffiliated withDepartment of Geological Sciences, Indiana University Email author 

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A thermodynamic dataset for arsenic species in As–O–H–S–Fe–Ba system was compiled from the literature. Using this dataset, Eh–pH diagrams for the systems As–O–H, As–O–H–S, As–O–H–S–Fe, As–O–H–Ba, and As–O–H–S–Fe–Ba were constructed at 25°C and 1 bar. The inclusion of thioarsenite species in the systems As–O–H–S and As–O–H–S–Fe results in substantial differences from previously published Eh–pH diagrams. There are considerable differences in the thermodynamic properties for orpiment, realgar, scorodite, arsenopyrite, barium arsenate, and barium hydrogen arsenate, which result in vastly different stability fields when different values are adopted.


Eh–pH diagrams Arsenic Compilation