# What are the resonance structures for CO_3^-2?

Jan 27, 2017

This is a carbonate ion. A resonance structure means that there are more than one way to draw the ion.

#### Explanation:

First, determine the total number of electrons available:

1 Carbon - 4
3 Oxygen - $6 \left(3\right) = 18$

And the charge of $- 2$ gives you an additional 2 electrons.

Hence, there are 24 electrons in total ($4 + 18 + 2 = 24$)

Carbon would be in the middle which gives you

However, note that carbon does not have a full octet shell. Hence, a pair of electrons from oxygen needs to come over and form a double bond. Note that the double bond can come from any oxygen atom which gives carbonate its resonance structure.