Revised Pourbaix Diagrams for Copper at 25 to 300°C

The Pourbaix diagrams (potential‐pH diagrams) for copper at 25 to 300°C have been revised. Extrapolation of thermochemical data to elevated temperatures has been performed with the revised model of Helgeson‐Kirkham‐Flowers, which also allows uncharged aqueous complexes, such as CuOH(aq) and , to be handled. Calculated high temperature thermodynamic data have been fitted against experimental data at elevated temperature. The hydrolysis of copper(I) and (II) is included with two and four hydroxide complexes, respectively. The Pourbaix diagrams show that the oxides and CuO(cr)) are stable at 25 to 200°C at 10−6 mol kg−1 of dissolved species, and at 300°C only CuO is stable. The oxides are stable at 25°C at 10−8 mol kg−1, but at 100 to 300°C no solid compound is stable.