In ternary and pseudo-ternary systems, the most natural representation is made from stacking phase triangles at a given temperature in the form of a prism, shown in black. In the case of extractants, the mole fraction of cation relative to anionic extractant (Z) governs spontaneous curvature and hence replaces the temperature as the edge of the prism. The figure shows on the left the two most used cuts in theoretical approaches that were introduced by Shinoda: the chi-cut (shown in magenta) and the “balanced” fish-cut (shown in green). On the right, the two cuts most used in chemical engineering to evaluate yields and safety of processes are shown: the Lund cut with constant water to extractant ratio (shown in red), the Lund cut with constant diluent to extractant ratio (shown in blue) and the formulator’s cut at overall constant water content (shown in dashed orange lines).