In inorganic chemistry, bicarbonate (IUPAC-recommended nomenclature: hydrogen carbonate) is an intermediate form in the deprotonation of carbonic acid. It is a polyatomic anion with the chemical formula HCO3−. Bicarbonate serves a crucial biochemical role in the physiological pH buffering system. The term “bicarbonate” was coined in 1814 by the English chemist William Hyde Wollaston. The prefix “bi” in “bicarbonate” comes from an outdated naming system and is based on the observation that there is two times as much carbonate (CO3) per sodium ion in sodium bicarbonate (NaHCO3) and other bicarbonates as in sodium carbonate (Na2CO3) and other carbonates.