Basic Copper Carbonate (WSDTY) is a generic term for a series of compounds, not just a composition of Cu2(OH)2CO3 (chemical formula). For example, the main component of natural malachite is basic copper carbonate. The chemical formula can be written as Cu2(OH)2CO3 or CuCO3·Cu(OH)2. The color is green, but there is also a natural ore called azurite. The main chemical formula can be Writing Cu3(OH)2(CO3)2 or 2CuCO3.Cu(OH)2, still known as basic copper carbonate, is blue in color. In fact, in the sodium carbonate solution, CO3 2- and OH- are simultaneously present in the solution due to the hydrolysis of the carbonate ions. After the addition of the copper sulfate solution, depending on the concentration of the reactants, a base having a different composition may be formed. Precipitation of copper carbonate, the basic formula of basic copper carbonate precipitation can be expressed as xCuCO3·yCu(OH)2, and can even be expressed as xCuCO3·yCu(OH)2·zH2O, which often has a very complicated structure, which can be interpreted as The hydroxide ion acts as a complex multinuclear complex of oxygen bridge. After a period of "aging" of the newly precipitated basic copper carbonate, the composition may also undergo some changes.
In general (presumably), the thicker the sodium carbonate solution, the higher the concentration of carbonate ions, the more likely it is to form a xCuCO3·yCu(OH)2 precipitate with a larger x value, and the color of the precipitate is more blue, so preparation In the case of basic copper carbonate Cu2(OH)2CO3, the method of adding sodium carbonate solution to copper sulfate solution should be adopted. It should not be reversed. When CO2 bubbles are emitted, slowly add sodium carbonate solution and stir well. , control the final solution pH should not be too high (pH = 8), and leave the precipitate for a period of time (can be placed for 24h), after the precipitation is fully aged, and then filtered and so on.
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