coordination number

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asannajust_1J
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coordination number

Postby asannajust_1J » Thu Dec 05, 2019 1:51 pm

How do you approach this problem? not sure of my answers... determine the coordination number of the metal ion in each of the following complexes: (a) [NiCl4]2–; (b) [Ag(NH3)2]1 ; (c) [PtCl2(en)2]21 ; (d) [Cr(edta)]2

Daria Azizad 1K
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Re: coordination number

Postby Daria Azizad 1K » Thu Dec 05, 2019 1:55 pm

I generally approach these problems by first identifying what ligands are in the coordinate sphere, so for (a), the ligand is chlorine. Since we know that Cl has a -1 charge and that there are four of them, that means the charge of nickel plus the charge of the chlorines will equal the charge of the compound. So, that means the charge of nickel will be 6+. For naming them, always start with the ligand and if there are multiple, go alphabetically.

asannajust_1J
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Re: coordination number

Postby asannajust_1J » Thu Dec 05, 2019 1:58 pm

How does that tell you the coordination number?

Anisha Chandra 1K
Posts: 118
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Re: coordination number

Postby Anisha Chandra 1K » Thu Dec 05, 2019 2:42 pm

The coordination number is just the number of bonds formed. So for A, the answer would be 4 bonds because 4 chlorines are bonded to one nickel atom.

ShravanPatel2B
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Re: coordination number

Postby ShravanPatel2B » Thu Dec 05, 2019 2:55 pm

the coordination number is found by observing how many ligands are attached to the central atom

Verity Lai 2K
Posts: 100
Joined: Sat Aug 24, 2019 12:18 am

Re: coordination number

Postby Verity Lai 2K » Thu Dec 05, 2019 4:54 pm

The coordination number is just the number of bonds on the central atom so I would draw the lewis structure so you have a visual and can easily identify the coordination number.

Daniel Toscano 1L
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Joined: Tue Nov 13, 2018 12:18 am

Re: coordination number

Postby Daniel Toscano 1L » Thu Dec 05, 2019 4:59 pm

to add on, be aware of polydentate ligands bonded to the metal as they also contribute to the coordination number. For example, if a metal is only bonded to 1 bidentate ligand than the coordination number would be 2 as the ligand is bonded to the metal 2 times


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