Calcium carbonate is an inorganic compound with the chemical formula CaCO3, which is the main component of limestone, marble, and other materials. Calcium carbonate is usually a white crystal, odorless, essentially insoluble in water, and easily reacts with acids to release carbon dioxide. It is one of the common substances on Earth, found in rocks such as aragonite, calcite, chalk, limestone, marble, and limestone, and is also a major component of certain animal bones or shells. Calcium carbonate is also an important building material with a wide range of industrial applications.

physical property:

Calcium carbonate is a white fine crystalline powder, odorless and tasteless. There are two forms: amorphous and crystalline. In the crystalline form, it can be divided into rhombohedral and hexagonal crystal systems (anhydrous calcium carbonate is a colorless rhombohedral crystal, hexahydrate calcium carbonate is a colorless monoclinic crystal [3]), which are columnar or diamond shaped with a density of 2.93g/cm3. The melting point is 1339 ℃ (decomposed at 825-896.6 ℃), and the melting point at 10.7MPa is 1289 ℃. Almost insoluble in water, soluble in water containing ammonium salts or ferric oxide, insoluble in alcohols.

chemical property

Calcium carbonate decomposes into calcium oxide and carbon dioxide at 825-896.6 ℃.

2. Calcium carbonate will bubble and dissolve with dilute acids (such as dilute acetic acid, dilute hydrochloric acid, dilute nitric acid, etc.). The reaction simultaneously releases carbon dioxide, resulting in an exothermic reaction.

3. Adding excess carbon dioxide to water mixed with CaCO3 will generate a solution of calcium bicarbonate. Calcium carbonate reacts with carbonate solution (rainwater) to produce calcium hydrogen carbonate. Inject CO2 into the turbid lime water, and the sediment disappears.

4. Anhydrous calcium carbonate (white, odorless, non-toxic powdery substance, light calcium carbonate) is heated to 1000K to transform into calcite (cubic crystal system, heavy calcium carbonate).