What is the formula for carbonate?

The formula for carbonate is represented as CO3^2-. This indicates that the carbonate ion consists of one carbon atom covalently bonded to three oxygen atoms, and carries a charge of -2. Carbonate is a polyatomic ion commonly found in various compounds such as calcium carbonate (CaCO3) and sodium carbonate (Na2CO3), and it plays a significant role in biological systems, geology, and industrial applications.

In contrast to the other options, HCO3^1- represents the bicarbonate ion, which is a different species that contains one hydrogen atom and has a different structure and charge. CrO4^2- is the chromate ion, which consists of chromium and oxygen, while NO2- refers to the nitrite ion, which includes nitrogen and oxygen. Each of these ions has distinct chemical properties and functions, which differentiate them from the carbonate ion.