Octahedral

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

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Victoria Luu - 1C
Posts: 60
Joined: Fri Sep 28, 2018 12:15 am

Octahedral

Postby Victoria Luu - 1C » Mon Nov 26, 2018 5:14 pm

What are the bond angles for an octahedral? Does it decrease when two bonded pairs are replaced with lone pairs, and the shape becomes square planar, or do the lone pair repulsions cancel out because they are directly across each other?

Jonas Talandis
Posts: 60
Joined: Fri Sep 28, 2018 12:16 am

Re: Octahedral

Postby Jonas Talandis » Mon Nov 26, 2018 5:20 pm

Every bond angle in an octahedron is 90 degrees. When there is one LP (Square Pyramidal) it is slightly less that 90 degrees. When it has 2 LPs (Square Planar) the repulsions cancel out and the bond angles are all 90 degrees. When there are three LPs it becomes T-Shaped with slightly less than 90 degrees and when it has 4 LPs it is linear with 180 degrees.

skyeblee2F
Posts: 62
Joined: Fri Sep 28, 2018 12:23 am

Re: Octahedral

Postby skyeblee2F » Mon Nov 26, 2018 5:21 pm

The bond angles are all 90º. Your second guess is correct; when there are two lone pairs, the repulsions cancel out and the square planar also has 90º angles.

Andonios Karas 4H
Posts: 30
Joined: Fri Sep 28, 2018 12:27 am

Re: Octahedral

Postby Andonios Karas 4H » Mon Nov 26, 2018 5:28 pm

The bond angles for octahedral molecular geometry are 90o and 180o. Whenever an long pair of electrons replaces a bonding pair, it will exert forces on adjacent bonding pairs and cause angles to become less than 90o.
Here is an image describing each electron geometry and angle size.
Image


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