CARBONATE

(1) The collective term for the natural inorganic chemical compounds related to carbon dioxide that exist in natural waterways. (2) A sediment formed by the organic or inorganic precipitation from aqueous solution of carbonates of calcium, magnesium, or iron. The CO3-2 ion in the Carbonate Buffer System. Combined with one proton, it becomes Bicarbonate, HCO3- and with two protons, Carbonic Acid. The carbonate ion forms a solid precipitant when combined with dissolved ions of calcium or magnesium.