Coordination Number

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Crystal Pan 2G
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Coordination Number

Postby Crystal Pan 2G » Sun Dec 06, 2020 8:55 pm

In the textbook problems that Dr. Lavelle has assigned, specifically 9C.9, it asks us to determine the coordination number of the metal ion in the following complexes. For c and d, it gives [PtCl2(en)2]^2+ and [Cr(edta)]^-. Without knowing the structure and formula of ethylenediamine and EDTA, how would we know the coordination number? Should we memorize the formula of (en) and (edta) for the final?

Gwendolyn Hill 2F
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Re: Coordination Number

Postby Gwendolyn Hill 2F » Sun Dec 06, 2020 8:56 pm

We might have to know them.... they're on the list of coordination compounds from his website;
https://lavelle.chem.ucla.edu/wp-content/supporting-files/Chem14A/NamingCoordinationCompounds.pdf

Sara_Lim_2C
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Joined: Wed Sep 30, 2020 9:55 pm

Re: Coordination Number

Postby Sara_Lim_2C » Sun Dec 06, 2020 8:59 pm

I think we do have to memorize what (en) and other shorthands for common ligands. For the first example, we should know that ethylenediamine is bidentate, so it will have two bonds to the central Platinum ion. And there's two of those, so that's four. And in addition, there's the 2 chlorine ions, so that's 6 bonds total, so the coordination number would be six. Hope that helps!

SophiaBarden 2E
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Re: Coordination Number

Postby SophiaBarden 2E » Sun Dec 06, 2020 8:59 pm

An en ligand is neutral and the edta ligand has a 4- charge. My TA mentioned that we should memorize these and the ones on the paper that Lavell posted on his website! He may provide teh charge but It is always better to be at least familiarized and more prepared for the final.
[url]https://lavelle.chem.ucla.edu/wp-content/supporting-files/Chem14A/NamingCoordinationCompounds.pdf[url][/url][/url]

Natalie 3k
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Joined: Wed Sep 30, 2020 10:11 pm

Re: Coordination Number

Postby Natalie 3k » Sun Dec 06, 2020 9:16 pm

This might be oversimplifying it, but I just remember that each en contributes 2 to the coordination number and each edta contributes 6 to the coordination number. I think we just have to memorize it but correct me if I'm wrong!


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