Chelating Ligands and Coordination Numbers

[Mariah]

Would our coordination number be raised by just counting the chelating ligand, or how many times it is chelated to the metal?

[Indy Bui 1l]

I don't think it would necessarily be raised, but if a molecule chelates then less of that molecule is needed to bond to the metal. So there would just be less ligands needed in the coordinating complex. The coordinate number doesn't increase but there are less ligands, so the charge on the metal seems to have a greater impact on the total complex.

[karinaseth_1A]

I don't think it would necessarily be raised, but if a molecule chelates then less of that molecule is needed to bond to the metal. So there would just be less ligands needed in the coordinating complex. The coordinate number doesn't increase but there are less ligands, so the charge on the metal seems to have a greater impact on the total complex.

So does the coordination number depend on the number of binding sites or the number of actual ligands bound to the metal? For example, if one EDTA molecule was bound to a metal, would the coordination number be 1 or 6?

[DHavo_1E]

I don't think it would necessarily be raised, but if a molecule chelates then less of that molecule is needed to bond to the metal. So there would just be less ligands needed in the coordinating complex. The coordinate number doesn't increase but there are less ligands, so the charge on the metal seems to have a greater impact on the total complex.

So does the coordination number depend on the number of binding sites or the number of actual ligands bound to the metal? For example, if one EDTA molecule was bound to a metal, would the coordination number be 1 or 6?

Hi,

Coordination number depends on the number of bonds on the central transition metal. Thus, the coordination number of the complex with the EDTA molecule and metal would be 6.

[Indy Bui 1l]

Yeah it would be six. I think I was a bit confused earlier when I was typing my answer. Sorry!