# How do you use the Lewis dot structure to represent hydrogen carbonate?

The carbonate dianion may be represented as $\left(O =\right) C {\left(- {O}^{-}\right)}_{2}$, with a formal negative charge on 2 oxygen atoms. Introduce an hydrogen ion, carbonate becomes bicarbonate, and the Lewis structure is $\left(O =\right) C \left(- {O}^{-}\right) \left(O H\right)$. There are 24 valence electrons involved in the bonding: 4 from carbon; 18 from oxygen; and 1 each from the negative charge and hydrogen.