Fig. 7

Predicted vs. experimentally measured \({\mathrm{K}}_{\mathrm{D},\mathrm{Fe}^{2+}-\mathrm{Mg}}^{\mathrm{ol}/\mathrm{liq}}\) values. The data set consists of the RKD experiments (n = 14) and the preferred low-ƒO₂ experiments (n = 187). A Model 2 (this study), B Ford et al. (1983), C Toplis (2005), D Blundy et al. (2020). The expression used to calculate Fe³⁺/Fe²⁺ for each model is: Borisov et al. (2018), (A); Sack et al. 1980, B; Kilinc et al. (1983) plus P₂O₅ term from Toplis et al. (1994), C. Symbols are the same as in Figs. 5B and 6A; a.a.d. refers to the average absolute deviation between the measured value and the value calculated using each model. The diagonal line in each panel is a 1:1 line. Error bars are 1σ