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Br 2+

Posted: Wed Dec 10, 2014 12:08 am
by 204301116
In one of the practice finals it says that Br 2+ is diamagnetic. Can someone please explain this to me? I thought it should be paramagnetic with 2 unpaired electrons.

Re: Br 2+

Posted: Wed Dec 10, 2014 12:15 am
by Shreyesi Srivastava 2D
Someone else had this issue and posted it here as well. If you do the molecular orbital diagram Br2 2+ is paramagnetic- it has unpaired electrons in the 3pi*x and 3pi*y. However, Br2 is diamagnetic as shown in this: http://chemwiki.ucdavis.edu/@api/deki/f ... revision=1

Is this a typo?

Re: Br 2+

Posted: Wed Dec 10, 2014 4:57 pm
by Sohaib Kazmi 4H
Br has 7 valence electrons, so Br2 should have 14. Br2 2+, however, should have 2 less electrons.

Br2 2+ should be paramagnetic because when you remove the 2 electrons, the 3pi-x and 3pi-y will be unpaired, like Shreyesi said. I'm pretty sure it's a typo, you could check with Lavelle.

Re: Br 2+

Posted: Thu Dec 11, 2014 2:37 pm
by Nikolina Walas-3J
how would you draw the MO diagram if there is a d shell filled?

Re: Br 2+

Posted: Thu Dec 11, 2014 4:48 pm
by Sohaib Kazmi 4H
The d-orbital shouldn't matter because it doesn't affect the valence electron count, which is what determines bond order and magnetism in the MO diagram. That being said I'd be interested to see how the d-orbital affects MO diagrams as well.

Re: Br 2+

Posted: Sat Dec 13, 2014 5:11 pm
by Nikolina Walas-3J
I actually don't think the D orbital would affect the MO diagram because its a lower energy level, so the valence would only be 4s and 4p

Re: Br 2+

Posted: Sat Dec 13, 2014 9:41 pm
by Nicole Ng IC
I had the same problem.
When you remove the two electrons, one is from the pi*px and one from the pi*py, so those two orbitals would be unpaired. Hence the molecule would be paramagnetic. I don't think d orbitals are involved in any way.
I might have been a typo because the answer key generalized the pi*p orbitals and wrote (pi*p)2, which is actually pi*px1 and pi*py1

Re: Br 2+

Posted: Sat Dec 13, 2014 11:37 pm
by Chelsea Zeng 4E
So just double checking.... it is a typo right?