T shape

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005321227
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Joined: Sat Sep 07, 2019 12:15 am

T shape

Postby 005321227 » Fri Nov 15, 2019 12:24 am

Can someone explain T shape and give an example of a molecule with the T shape?

Jedrick Zablan 3L
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Re: T shape

Postby Jedrick Zablan 3L » Fri Nov 15, 2019 12:39 am

A T-Shape is created when there is one central atom with two lone pairs and three bonded atoms. The shape comes from the electron repulsion of the lone pairs. Some examples are ClF3 and BrF3.
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KDang_1D
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Re: T shape

Postby KDang_1D » Fri Nov 15, 2019 3:38 pm

Why wouldn't this be a trigonal planar shape with the electron clouds in the axial positions? Didn't we talk about the electron clouds wanting to be as far apart as possible to minimize repulsion and make the molecule more stable?

904914037
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Joined: Wed Sep 18, 2019 12:16 am

Re: T shape

Postby 904914037 » Fri Nov 15, 2019 3:58 pm

You can also think of it in the sense that anytime you have the VESPR formula of AX3E2, you will have a T-shaped structure.

904914037
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Re: T shape

Postby 904914037 » Fri Nov 15, 2019 4:06 pm

KDang_1E wrote:Why wouldn't this be a trigonal planar shape with the electron clouds in the axial positions? Didn't we talk about the electron clouds wanting to be as far apart as possible to minimize repulsion and make the molecule more stable?


I do not have a definite answer for this, but I like to look at it based on how many areas of electron density are surrounding the central atom. In this case it would be five which would correspond to the trigonal bipyramidal shape. If you were to take away two of the equatorial atoms of a trigonal bipyramidal you would get a t-shaped molecule. This is similar to what Professor did in class today, having people remove atoms from his model to reveal where the lone pairs would be. I believe he said that which electrons are taken away is based on the most stable structure with the least amount of large angles separating the atoms, but I am not 100% sure about this.

WesleyWu_1C
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Re: T shape

Postby WesleyWu_1C » Fri Nov 15, 2019 6:03 pm

The reason why the molecule would not be a trigonal planar is because trigonal planar means that the bound atoms are about 120 degrees away from each other, but that would not make sense because there are 2 lone pairs which means there is very strong repulsion between the lone pairs and the lone pair and the covalent bonds. This repulsion would change the bond angles.

Maeve Miller 1A
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Re: T shape

Postby Maeve Miller 1A » Fri Nov 15, 2019 7:49 pm

T shape occurs in AX3E2--when an electronically geometric trigonal bipyramidal molecule has 2 lone pairs, leaving it T shaped with bond angles of 90 and 180 degrees.

904914037
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Re: T shape

Postby 904914037 » Sun Nov 17, 2019 10:27 am

I also read in the textbook that most of the time, it is more stable to have equatorial lone pairs rather than axial pairs, which would explain how you get a T-shape from the trigonal bipyramidal electron arrangement of an AX3E2 molecule.


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