Seesaw Shape

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

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Mackenzie Fernandez 3G
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Seesaw Shape

Postby Mackenzie Fernandez 3G » Sun Nov 29, 2020 10:59 am

hi!

I was wondering if someone could explain the seesaw thing Dr. Lavelle mentioned in lecture. I don't really understand the concept.

thank you!

Lucy Wang 2J
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Re: Seesaw Shape

Postby Lucy Wang 2J » Sun Nov 29, 2020 11:20 am

The seesaw shape applies to when there are 5 areas of electron density. One area is a lone pair and the other 4 are bonds. When this happens, it leads to a seesaw structure.

Shalyn Kelly 3H
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Re: Seesaw Shape

Postby Shalyn Kelly 3H » Sun Nov 29, 2020 11:29 am

As the post above states, it kind of looks like a seesaw. Two bonds are at the bottom forming a somewhat triangular shape, with two more bonds balancing on top (where if you "bounced" them they'd tilt like a seesaw). I guess you could also pretend the lone pair are kids on the seesaw as well? Though they aren't really in the right place for it, it might help with remembering there's one lone pair in a seesaw shape.

George Cazares 1E
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Re: Seesaw Shape

Postby George Cazares 1E » Sun Nov 29, 2020 11:31 am

The seesaw shape refers to a molecule with five regions of e- density with four bonding regions and one lone pair. The seesaw shape has bond angles of <120 and <90. SF4 would be an example of a seesaw shape.

Ansh Patel 2I
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Re: Seesaw Shape

Postby Ansh Patel 2I » Sun Nov 29, 2020 11:37 am

Hi! A molecule has a seesaw shape when there are 5 electron density regions, where four are bonds and one is a lone pair. The bond angles for this shape are <120 and <90.

Mikayla James 2A
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Re: Seesaw Shape

Postby Mikayla James 2A » Sun Nov 29, 2020 11:37 am

Hi! like other people have said above, in a seesaw shape, there is 5 regions of electron density with 4 bonding pairs and 1 lone pair. 5 regions of electron density would normally be a trigonal bipyramidal shape, but because lone pairs are not used to name the shape, we replace one of the atoms in the trigonal bipyramidal shape with the lone pair. It matters which position you place the lone pair in, so you would place it in the horizonal plane to limit lone pair-bonding pair interactions and this positioning of the lone pair results in the seesaw shape. Hope this helps!


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