n.
Any member of two classes of chemical compounds
one inorganic and the other organic
that are derived from carbon dioxide (CO 2 ) or its water solution, carbonic acid (H 2 CO 3 ).
Inorganic carbonates (MCO 3 or M 2 CO 3 , where M is a metal atom of, e.g., calcium or sodium ) are salt s of carbonic acid. The shells and other hard parts of shellfish are calcium carbonate, as is the limestone they turn into. Many other minerals, including calcite , dolomite , and aragonite , consist of or contain carbonates. Sodium carbonate is one of the world's most important basic chemical commodities. Organic carbonates are ester s of carbonic acid and various alcohol groups (methyl, ethyl, or phenyl). These are liquids used as solvent s and to synthesize plastics and other compounds.