The carbonate ion is a polyatomic ion with the chemical formula CO32-. It consists of one carbon atom (C) and three oxygen atoms (O), arranged in a trigonal planar structure. The overall charge of the carbonate ion is -2.
This charge arises because the carbon atom forms double bonds with two of the oxygen atoms and a single bond with the third oxygen atom, which carries an extra electron. The presence of this extra electron on the third oxygen atom results in the overall negative charge of the ion.
Carbonate ions are commonly found in various minerals, such as limestone and marble, and play a crucial role in the carbon cycle, including the formation of carbonic acid in water.