The thermodynamically stable form of<unk>  under normal conditions is hexagonal β-CaCO3 (the mineral calcite). Other forms can be prepared, the denser (2.83 g/cm3) orthorhombic λ-CaCO3 (the mineral aragonite) and hexagonal μ-CaCO3, occurring as the mineral vaterite. The aragonite form can be prepared by precipitation at temperatures above 85 °C; the vaterite form can be prepared by precipitation at 60 °C. Calcite contains<unk>  atoms coordinated by six oxygen atoms; in aragonite they are coordinated by nine oxygen atoms. The vaterite structure is not fully understood. Magnesium<unk>  (MgCO3) has the calcite structure, whereas strontium<unk>  and barium<unk>  (SrCO3 and<unk>  adopt the aragonite structure, reflecting their larger ionic radii.
Calcium carbonate
Strontium ranelate
Potassium fluoride
Sodium fluoride
Lanthanum carbonate
Aluminum chloride hexahydrate
Calcium fructoborate
Magnesium citrate