Polarity and Nonpolarity

(Polar molecules, Non-polar molecules, etc.)

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HimaniMadnawat3L
Posts: 15
Joined: Fri Sep 26, 2014 2:02 pm

Polarity and Nonpolarity

Postby HimaniMadnawat3L » Sat Oct 25, 2014 7:05 pm

How can a molecule can have polar bonds but be nonpolar overall. Can the opposite ever be true?

Sarah H Brown 1L
Posts: 56
Joined: Fri Sep 26, 2014 2:02 pm

Re: Polarity and Nonpolarity

Postby Sarah H Brown 1L » Mon Oct 27, 2014 4:51 pm

In lecture we discussed BeCl2. This molecule is linear because the chlorines each have 3 lone pairs and are each bonded to Be with a single bond (Be has 0 lone pairs). The furthest apart the two regions of Cl electron density can be is directly opposite with Be in the center. However, there are two dipole moments on BeCl2. They each point to Cl because Cl is more electronegative than Be. Because the chlorines are 180 degrees apart, they have dipole moment vectors of the same magnitude in the opposite directions and therefore, the dipole moments cancel each other out. Basically, BeCl2 has polar bonds that cancel each other out so the overall molecule is nonpolar. Addressing your second question, the opposite would be a polar molecule that has all nonpolar bonds. As far as I know, this does not exist.

HimaniMadnawat3L
Posts: 15
Joined: Fri Sep 26, 2014 2:02 pm

Re: Polarity and Nonpolarity

Postby HimaniMadnawat3L » Tue Oct 28, 2014 7:26 pm

Thank you!


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