Sapling #5 for Week 9

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Melody Haratian 2J
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Sapling #5 for Week 9

Postby Melody Haratian 2J » Mon Nov 30, 2020 4:31 pm

Hi guys!
I was doing the sapling HW for week 9 and got stuck on #5. What does the “en” in [Cd(en)Br2] mean? Also, how would you find the coordination number for this molecule?

Melody Wu 2L
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Re: Sapling #5 for Week 9

Postby Melody Wu 2L » Mon Nov 30, 2020 4:35 pm

en is shorthand for the ethylenediamine ligand, which is bidentate. Since Br has one bonding site and there are two of them, plus the two bonding sites on the ethylenediamine ligand, there's a total of 4 bonding sites. Therefore the coordination number would be 4.

Darlene Lien 3E
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Re: Sapling #5 for Week 9

Postby Darlene Lien 3E » Mon Nov 30, 2020 4:41 pm

Hi, also, I think Dr. Lavelle posted a worksheet on his website that would help with naming coordination compounds, so definitely check that out! Hope this helps!

Juliet Cushing_2H
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Re: Sapling #5 for Week 9

Postby Juliet Cushing_2H » Mon Nov 30, 2020 6:04 pm

I got that one wrong too and Sapling popped up saying that en stands for "ethylenediamine" which is a bidentate molecule. Each molecule can bind to the TM twice, so (en)2 will occupy 4 bonding regions! This will help find out the coordination number.

Scot Widjaja Dis 1J
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Re: Sapling #5 for Week 9

Postby Scot Widjaja Dis 1J » Sun Dec 06, 2020 4:50 am

en stands for ethlyenediamine and it is a bidentate ligand, meaning it can donate two electron pairs to the central transition metal cation. In other words, it can form two bonds with the metal. Knowing this, and knowing the compound formula is [Cd(en)Br2], we know that the coordination number will be 4, since en forms 2 bonds and each Br forms 1 bond, giving a total of 4 bonds.

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