VSEPR Shapes and Lone Pair Electrons on central atom

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704578485
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Joined: Fri Sep 25, 2015 3:00 am

VSEPR Shapes and Lone Pair Electrons on central atom

Postby 704578485 » Tue Oct 20, 2015 5:16 pm

I was just doing the VSEPR and molecular shape homework problems and a few questions came to mind. I'm using the 5th edition of the book so I am not sure if the problem numbers will correspond to the newer version. First, on Chapter 3 #9b the ICl3 molecule is said to take on a T shape with 2 lone electron pairs on the central atom. I do not remember discussing a T shape in class. Do we need to be aware of this structure or any others not covered in lecture? Also, on Chapter 3 #11 the I3^- ion is said to have a linear shape. This confuses me because the central iodine atom has 3 pairs of lone electrons. This concept also came up in Chapter 3 #1. I though if you had a linear structure no lone pairs of electrons could be on the central atom. What is the explanation for having a linear structure with lone pairs on the central atom?

Julia Kim 1D
Posts: 63
Joined: Fri Sep 25, 2015 3:00 am

Re: VSEPR Shapes and Lone Pair Electrons on central atom

Postby Julia Kim 1D » Tue Oct 20, 2015 6:13 pm

If you have a linear structure with lone pairs, it simply means that the repulsion of the lone pairs act equally on the other two molecules so that they aren't pushed past the 180 bond angle. For example, If you had a molecule of AX2E3, it would still be considered linear. (It is trigonal bipyramidal in form, but you remove the 3 atoms in the trigonal planar plane.


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