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Multiple different bond angles

Posted: Sun Nov 18, 2018 8:45 pm
by KylieY_3B
Why do some structures have bond angles of different degrees? For example, in my discussion section we used the example of TeCl4 as having angles of both 120 degrees and 90 degrees. Also, how do we determine when this is the case?

Re: Multiple different bond angles

Posted: Sun Nov 18, 2018 8:58 pm
by Germar G 4F
TeCl4 has different bond angles because of its molecular geometry. It has seesaw geometry, since it has 4 single bonds and one lone pair. All seesaw geometries will have 90, 120, and 180 degree angles in their 3-D shape. If you look at a picture of "seesaw geometry" you can see each of the angles.

Re: Multiple different bond angles

Posted: Sun Nov 18, 2018 9:02 pm
by KylieY_3B
Germar G 4F wrote:TeCl4 has different bond angles because of its molecular geometry. It has seesaw geometry, since it has 4 single bonds and one lone pair. All seesaw geometries will have 90, 120, and 180 degree angles in their 3-D shape. If you look at a picture of "seesaw geometry" you can see each of the angles.


Thank you! Is the easiest way to determine bond angles simply to memorize it in accordance with the shape?

Re: Multiple different bond angles

Posted: Sun Nov 18, 2018 9:10 pm
by whitney_2C
If you click on this link you can download a software that shows molecules in 3D and you can move them around so you have a better idea of the shapes and angles! If that doesn't help you with remembering molecule bond angles for different shapes then I would just memorize them.

Re: Multiple different bond angles

Posted: Sun Nov 18, 2018 9:11 pm
by whitney_2C

Re: Multiple different bond angles

Posted: Sun Nov 18, 2018 10:13 pm
by KylieY_3B
whitneyh_4_4G wrote:If you click on this link you can download a software that shows molecules in 3D and you can move them around so you have a better idea of the shapes and angles! If that doesn't help you with remembering molecule bond angles for different shapes then I would just memorize them.


Wow! Thank you!

Re: Multiple different bond angles

Posted: Sun Nov 18, 2018 10:52 pm
by uhedlund
Yes, having different molecular geometry results in the angles between different atoms being different sizes. Lone pairs can play a role in this geometry.