# Based on hybridization, how would you predict the shape of the CO_3 (2-)ion?

Apr 4, 2016

Trigonal planar, with 2 formal negative charges on the oxygen atoms.

#### Explanation:

There are $4 + \left(3 \times 6\right) + 2 = 24 \text{ electrons}$ to distribute around 4 centres. A reasonable resonance isomer is $\left(O =\right) C {\left(- O\right)}_{2}^{-}$. Since there are three bonding pairs of electrons around the central carbon, trigonal planar geometry is indicated. Clearly, by resonance, all the $C - O$ bonds are equivalent.