Karbonaattiryhmä

Karbonaattiryhmä, chemical formula CO3^2-, is a polyatomic anion composed of one carbon atom and three oxygen atoms. It carries a net charge of -2. The carbon atom is covalently bonded to each of the three oxygen atoms, with the bonding exhibiting resonance, meaning the electrons are delocalized across the oxygen atoms. This resonance contributes to the stability of the carbonate ion.

Carbonate is a fundamental building block in inorganic chemistry and is found in a vast array of minerals, most notably in the carbonate mineral group. Rocks like limestone, marble, and chalk are primarily composed of calcium carbonate (CaCO3), a common example of a carbonate salt. Other important carbonate minerals include dolomite (CaMg(CO3)2) and siderite (FeCO3).

In solution, carbonate ions can participate in various chemical reactions. They are the conjugate base of the bicarbonate ion (HCO3^-) and the carbonic acid molecule (H2CO3). The solubility of carbonate salts varies greatly; while many alkali metal carbonates (like sodium carbonate, Na2CO3) are soluble in water, the carbonates of alkaline earth metals (like calcium carbonate, CaCO3) and transition metals are generally insoluble.

The presence of carbonate ions is significant in natural systems, playing a role in the Earth's carbon cycle and influencing the pH of aquatic environments. Industrially, carbonates are used in the production of cement, glass, and detergents, and in applications such as water treatment.