Explain the structure of `CO_(3)^(2-)` ion in terms of resonance
(b) Explain the resonance structures of `CO_(2)` molecule .

Explanation

The experimentally determined carbon to oxygen bond length in `CO_(2)` is 115 pm. The lengths of a normal carbon to oxygen double bond `(C=O)` and carbon to oxygen triple bond `(C-=O)` are 121 pm and 110 pm respectively. The carbon-oxygen bond lengths in` CO_(2)` (115 pm) lie between the values for `C=O` and `C-=O`. Obviously, a single Lewis structure cannot depict this position and it becomes necessary to write more than one Lewis structures and to consider that the structure of `CO_(2)` is best described as a hybrid of the canonical or resonance forms I, II and III
`{:( :overset(..)O::C::" "overset(..)O:, harr,:underset(..)overset(..^(-))O:Cvdotsvdotsoverset(+)O:, harr,:overset(+)OvdotsvdotsC:underset(..)overset(..^(-))O: ),(" "I,," "II,," "III):}`
Resonance in `CO_(2) molecule. I,II and III represent the three canonical forms.