Monodentate and Bidentate Ligands

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Cassidy Kohlenberger 3D
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Joined: Wed Sep 18, 2019 12:19 am

Monodentate and Bidentate Ligands

Postby Cassidy Kohlenberger 3D » Sat Nov 30, 2019 9:57 pm

In homework problem 9C.5, (CO3)2- is revealed to be both monodentate and bidentate. Can someone explain how this is possible? Also, are there any other ligands that fall under this category we need to know?

Jonathan Gong 2H
Posts: 105
Joined: Sat Jul 20, 2019 12:16 am

Re: Monodentate and Bidentate Ligands

Postby Jonathan Gong 2H » Sun Dec 01, 2019 12:03 pm

When you draw the Lewis structure of CO3^2-, one resonance has C=O double bond and 2 C-O^1- single bonds, these two O^1- are capable of binding to a metal center at 2 places, therefore making it a bidentate ligand. A different resonance of CO3^2- has the double bond between the two C-O bonds, leaving only one O- to be able to bind to the metal center, therefore making CO3^2- a monodentate ligand. I'm sure that there are a few more ligands under this category, you would just have to draw their lewis structures to find out.

Posts: 107
Joined: Fri Aug 02, 2019 12:16 am

Re: Monodentate and Bidentate Ligands

Postby 105311039 » Sun Dec 01, 2019 12:32 pm

How I look at it when i am determining such things like monodentate or polydentate is the charges. On CO3^2- there are two oxygens with a negative charge and one without. Therefore, there can either be two places for a transition metal to attach since they are both negatively charged. Or the transition metal can ignore the two negatively charged anions and attach to the neutral oxygen.

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