Calcium Carbonate Equilibrium

Calcium carbonate equilibrium involves a balance between calcium carbonate (CaCO₃), its dissolved forms calcium ions (Ca²⁺) and carbonate ions (CO₃²⁻), and its solid form (like limestone or chalk). When conditions change—such as pH, CO₂ levels, or temperature—this balance shifts, causing calcium carbonate to either dissolve or precipitate. For example, higher acidity fosters dissolution, releasing calcium and carbonate ions, while in neutral or alkaline conditions, these ions combine and form solid calcium carbonate again. This equilibrium is vital in natural processes like shell formation, sediment formation, and maintaining water quality.