# In the carbonate anion, which atoms gain the two electrons?

In the carbonate ion ($\ce{CO3^2-}$), is it the oxygen or the carbon that has gained the two additional electrons?

• The two additional electrons (no, you cannot tell which electrons are extra because all electrons are the same) are mainly delocalized between the three oxygen atoms (carbon atom should also share a tiny proportion of the extra charge). – DHMO Jan 11 '17 at 10:31

Here you can see that you can draw the ion like this, with one of the oxygen atoms having a double bond with the carbon, and the other two having a single bond. This means that the double bonded oxygen atom has no charge. The single bonded oxygen atoms have a net charge of $-1$ each as they have gained a lone pair of electrons.