Thermodynamic Properties of the Aqueous Ions (2+ and 3+) of Iron and the Key Compounds of Iron

Abstract

Recommended thennochemical property values, AfHo, ArGo, and So for the aqueous ions of iron, F~+ and Fe 3 +, are given at 298.

Determination of melanterite-rozenite and chalcanthite-bonattite equilibria by humidity measurements at 0.1 MPa

“…These derived thermodynamic data were compared with previously published data in Table 2. Adopting the value of -2507.75 ± 1.0 kJ/mol for ∆G f 0 , which corresponds to the standard Gibbs free energy of formation from elements at 298.15 K and 0.1 MPa, for melanterite suggested by Parker and Khodakovskii (1995), the ∆G f 0 for rozenite calculated from our ∆G r 0 datum for reaction 1 at 25 °C is -1794.9 ± 1.3 kJ/mol. Similarly, adopting the value of -1879.75 kJ/mol for ∆G f 0 for chalcanthite suggested by Wagman et al (1982), the ∆G f 0 for bonattite calculated from our datum for reaction 2 at 25 °C is -1399.96 kJ/mol, essentially the same value as suggested by Wagman et al (1982).…”

A New Method for the Prediction of Gibbs Free Energies of Formation of Hydrated Clay Minerals Based on the Electronegativity Scale

“…These differences are related to the poor choice of AG~ of Fe z+ and Fe 3+ for the prediction of solubility products of end-members (Fe2+: -78.9 kJ/mole, Fe3+: -4.7 kJ/mole). Values of AG7 for aqueous ferrous and ferric iron from Parker and Khodakovskii (1995) are used here. These values enable a new scale of Act = Mz+(aq) values in octahedral coordination to be determined.…”

Research Project on CO2 Geological Storage and Groundwater Resources: Water Quality Effects Caused by CO2 Intrusion into Shallow Groundwater

“…see Nordstrom (1984) and Reardon and Beckie (1987). Recent work on the solubility of siderite (Preis and Gamsjager, 2002) provides support for the validity of the properties of Fe 2+ in the survey by Parker and Khodakovskii (1995 Table C13.…”

“…Recent studies have revealed respectively the possible existence of substantial errors in the Gibbs free energy of formation of magnesite and dolomite (Rock et al, 2001). Furthermore, the experimental consistency of siderite solubility data (Preis and Gamsjager, 2002) has been recently established, and by inference, validated the thermodynamic data for ferrous and ferric ions recommended by Parker and Khodakovskii (1995). These modifications also require a redetermination of the thermodynamic properties of the ankerite solid solution utilized in earlier work (Xu et al, 2003).…”