Stalactite of the abundance of limestone caves. The corresponding formation on the floor of the cave is known as a stalagmite. The most common stalactites are speleothems, which occur in limestone caves. They form through deposition of calcium carbonate and other minerals, which is precipitated from mineralized water solutions. Limestone is the chief form of calcium carbonate rock which is dissolved by water that contains carbon dioxide, forming a calcium bicarbonate solution in underground caverns. The chemical formula for this reaction is: This solution travels through the rock until it reaches an edge and if this is on the roof of
Calcium carbonate caves. Two hydrated phases of calcium carbonate, monohydrocalcite, CaCO·HO and ikaite, CaCO·6HO, may precipitate from water at ambient conditions and persist as metastable phases. In contrast to the open equilibrium scenario above, many swimming pools are managed by addition of sodium bicarbonate (NaHCO) to about 2 mM as a buffer, then control of pH through use of HCl, NaHSO, NaCO, NaOH or chlorine formulations that are acidic or basic. In this situation, dissolved inorganic carbon (total inorganic carbon) is far from equilibrium with atmospheric CO. Progress towards equilibrium through outgassing of CO is slowed by (i) the slow reaction HCO