Bicarbonate ion (HCO₃⁻)

The **bicarbonate ion** (HCO₃⁻), also known as **hydrogen carbonate**, is a polyatomic anion that plays a central role in maintaining physiological pH balance through its function as part of the body's primary buffer system. It forms via the reversible dissociation of carbonic acid and serves as both a conjugate base to carbonic acid and a conjugate acid to carbonate. In biological systems, it helps regulate blood pH by neutralizing excess acids or bases, facilitates CO₂ transport from tissues to lungs for exhalation, and participates in cellular volume regulation. While essential for homeostasis, it is not considered a therapeutic target such as an enzyme or receptor but rather an important physiological molecule whose concentration serves as a clinical biomarker for various metabolic conditions.

Other names

Hydrogen carbonateHydrogencarbonateCarbonic acid ionHydroxidodioxidocarbonate(1−)CHO₃⁻