Hydrogen carbonate (bicarbonate) ion (HCO₃⁻)
- Charge
- −1
- Atoms
- H, C, O × 3
- Atoms in total
- 5
- Mass of the ion
- 61.016 g/mol
Hydrogen carbonate, better known as bicarbonate, is a carbonate ion that has picked up one hydrogen ion, so it contains one hydrogen, one carbon and three oxygen atoms. Adding H⁺ to the 2− carbonate ion cancels one negative charge, leaving bicarbonate with a 1− charge. You meet it in baking soda, antacid tablets and your blood, where it helps keep the pH steady.
- The word hydrogen in the name, or the older prefix bi-, shows that one H⁺ has been added to an ion, making its charge one step less negative.
- Bicarbonate sits between carbonic acid, H₂CO₃, and carbonate, CO₃²⁻, so it can react with both acids and bases.
- Baking soda is sodium hydrogen carbonate, NaHCO₃; with an acid it releases the carbon dioxide that makes dough rise.
Compounds that contain hydrogen carbonate (bicarbonate)
NaHCO3 Sodium hydrogen carbonate
KHCO3 Potassium hydrogen carbonate
NH4HCO3 Ammonium hydrogen carbonate