Carbonate ion
Charge: 2- · Type: Polyatomic anion · Molar mass: 60.008 g/mol
Made of: carbon, oxygen
How it forms
Carbonic acid loses two protons to give CO3^2-. Acids convert carbonate back to carbon dioxide gas, which is why vinegar fizzes on limestone and baking soda.
Naming note
CO3^2- is the carbonate ion; HCO3- is bicarbonate (hydrogen carbonate). Metal carbonates are named directly, as in calcium carbonate.
Examples in compounds
Calcium carbonate
Sodium carbonate
Magnesium carbonate