(a) Schematic ternary phase diagram for a congruently-dissolving CC. The three thick solid lines are the API solubility line, the CC solubility line, and the CF solubility line (from left to right). The thin solid lines indicate the phase boundaries, the thin dash-dotted line marks the CC stoichiometry. Dotted lines are iso-RH lines at DRHCC, DRHCC/API, and the DRHCC/CF; (b) Schematic phase diagram showing the thermodynamically-stable phases for a congruently-dissolving CC as function of the API/CF mass fraction in the dry system. Thick solid lines are deliquescence lines: API deliquescence, CC deliquescence line, and CF deliquescence line (from left to right). Thin solid lines indicate the phase boundaries, the thin dash-dotted line marks the CC stoichiometry. Dotted lines are the iso-RH lines at DRHCC, DRHCC/API, and the DRHCC/CF. The shaded region shows the presence of a liquid phase. The circles shown in (a,b) represent the equilibrium phases evolving at DRHCC.