f(O2) vs. pH iron stability diagram at 25°C and 1 bar showing the natural domains of the main groups of iron oxidizing bacteria recalculated from an Eh–pH diagram in Lundgren and Dean. Activities of dissolved iron, carbonate, and sulfur species are 10-6, 10° and 10-6, respectively, from Garrels and Christ. The boundary between Fe3+ and Fe2+ which is missing in the Lundgren and Dean diagram, has been added here. Other thermodynamic databases suggest the presence of FeHCO+3 supplanting siderite between 6.4 and 7.0 pH and acetates supplant other phases and species below -75 logf(O2).
Boyd and Scott Geochemical Transactions 2001 2:45 doi:10.1186/1467-4866-2-45