Bicarbonate

Bicarbonate is an anion (a negatively-charged ion). Its chemical formula is HCO−3. A sample compound is sodium bicarbonate.

The bicarbonate anion is formed with a carbon double-bonded to an oxygen, single-bonded to a hydroxide group, which here is neutral, and single-bonded to another oxygen which requires one more electron to complete its outer shell. Here, the sodium cation provides the electron, resulting in a net -1 charge.

Properties

Bicarbonate is amphoteric: it is both an acid and a base. As an acid, it reacts with bases to make carbonate, and as a base, it reacts with acids to make carbonic acid, which usually disporportionates to water and carbon dioxide.^[1]

When heated, it will react with itself as both acid and base: 2 NaHCO₃ → Na₂CO₃ + H₂O + CO₂