Copper carbonate is immediately hydrolyzed into a mixture of basic copper carbonate and copper hydroxide in the presence of water, and copper carbonate is not present in the aqueous solution, which is also the reason why the copper carbonate in the chemical textbook solubility table is “-“.
The copper hydroxide is dissolved in a potassium carbonate solution to form a deep blue coordination ion solution. Copper salt solution and excess potassium carbonate form K2[Cu(CO3)2] (dark blue), K2[Cu(CO3)2]·2H2O (bright blue) and K2[Cu(CO3)2]·4H2O (shallow Blue-green) complex.
The basic copper carbonate has a blue or green color depending on the composition (described above) and is an amorphous powder of fine particles having a density of 3.85. The degree of hydrolysis is extremely large, soluble in acid and forming a corresponding copper salt, dissolved in an aqueous solution of a carbonate of cyanide, sodium hydroxide, ammonium salt and alkali metal to form a copper complex. When boiled in an alkali metal carbonate solution, brown copper oxide is formed and decomposed into black copper oxide at 200 °C. Unstable in hydrogen sulfide atmosphere. Basic copper carbonate has more than ten forms of compounds depending on the ratio of CuCO3:H2O. In industrial production, the molecular formula is CuCO3·Cu(OH)2·xH2O. The solubility in water is 0.0008% and the decomposition temperature is 200-220 °C. Low toxicity. [4]
In addition, it should be noted that the reaction of sodium carbonate with a copper salt produces a mixture of basic copper carbonate and copper hydroxide, the specific composition depending on the reaction conditions, which is caused by the severe hydrolysis of sodium carbonate.
Main use of copper carbonate
Prepare other copper salts. Solid phosphor activator. Insecticides. Seed treatment fungicide. There is no practical application of paint copper carbonate. Basic copper carbonate can be used to prepare other copper salts, solid phosphor activators, insecticides, seed treatment fungicides, paints and the like.