Copper Carbonates

carbonate salts of copper. Normal copper carbonate has not been isolated yet. Copper carbonate (basic) occurs in nature as the emerald green mineral malachite, CuCO₃ · Cu(OH)₂, and the sky blue mineral azurite, 2CuCOa. Cu(OH)₂. The basic carbonate CuCO₃ - Cu(OH)₂ · 0.5H₂O is obtained by the action of Na₂CO₃ on CuSO₄ in an aqueous solution; upon heating, the carbonate is converted into malachite.

Copper carbonates are unstable and at temperatures above 200°C break down into CuO, CO₂, and H₂O. They are insoluble in water but can be dissolved in ammonia in the presence of ammonia salts. Azurite is used as a pigment; it is also used in pyrotechnics, metallurgy, and other industries. Both azurite and malachite are used in the fashioning of decorative objects and jewelry.