Textbook 9C.5

[Kaleigh Olla 1L]

For 9C.5, which asks "Which of the following ligands can be polydentate? If the ligand can be polydentate, give the maximum number of places on the ligand that can bind simultaneously to a single metal center:"

b) (CO3)2-

How can it be mono OR bidentate? I know it has one double bond on one of the oxygens, so wouldn't it just be classified as bidentate?

[patienceokani]

The reason why the compound (CO3)2- is polydentate is because of the possible resonance structure for that compound. The structure with a CO double bond proves that it is a monodentate because it is possible for something to bond at one site and then the other one (two C-O bonds) will show that it is bidentate since there are two places something can bind.