Why is AX3E2 linear?

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Katherine Fitzgerald 1A
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Why is AX3E2 linear?

Postby Katherine Fitzgerald 1A » Mon Jul 22, 2019 8:04 pm

I'm having a hard visualizing / conceptualizing why AX3E2 is linear. Can someone walk me through the logic?

David Zhang 1B
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Re: Why is AX3E2 linear?

Postby David Zhang 1B » Mon Jul 22, 2019 10:05 pm

AX3E2 is more a T-shaped molecule with the bound atoms in a side-ways T-shape. Imagine the trigonal bipyramidal structure of AX5 but remove two of the bound atoms of the trigonal part of the molecule.

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Re: Why is AX3E2 linear?

Postby hannabarlow1A » Tue Jul 23, 2019 10:31 am

We base the electron pair geometry on the number of regions of electron density surrounding the central atom (5), so it is trigonal bipyramidal. For the molecular geometry, we look at the bonds specifically. The bonds between the 3 surrounding atoms with the central atom create a T-shaped geometry.

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Re: Why is AX3E2 linear?

Postby Chem_Mod » Tue Jul 23, 2019 1:14 pm

AX3E2 is not linear. It is T-shaped. An example of this VSEPR type is ClF3. It has three fluorine atoms and one Cl atom as the central atom. It has two lone pairs and has three bonds. The three fluorine atoms are arranged around the central Cl atom to form a T-shaped molecule.

Jennifer Zhou 1A
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Re: Why is AX3E2 linear?

Postby Jennifer Zhou 1A » Tue Jul 23, 2019 3:16 pm

AX3E2 is T shaped. There are 5 electron densities regions, so we can see consider it as trigonal pyramidal with 2 bonding pair changed into lone pair. Changing the pairs on the trigonal planar is more stable, hence resulting the T-shaped. I think this picture shows the shape clearly.
ax3e2.gif (7.91 KiB) Viewed 623 times

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Re: Why is AX3E2 linear?

Postby George_Zhu » Tue Jul 23, 2019 5:56 pm

AX3E2 should be a T-shape instead of a linear, because it has other two lone pairs to push the other three bond away

Brian Kwak 1D
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Re: Why is AX3E2 linear?

Postby Brian Kwak 1D » Wed Jul 24, 2019 10:55 am

AX3E2. From this we can see that the central atom has 5 areas of electron density so the shape is trigonal bipyramidal. Now when it comes to naming the shape only the molecules connected to it count towards its name and we can see that only 3 molecules are attached. Now for a trigonal bipyramidal when you have lone pairs you always remove the equatorial ones first because it interacts with the most molecules ( 4 molecule interactions vs 3 for axial position). Since there are two lone pairs it would be in the equatorial positions and so the shape is a t shape ( with 2 axial molecules and one equatorial molecule with a bond angles of 90 degrees relative to the axial molecules).

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Re: Why is AX3E2 linear?

Postby D-nice1D » Wed Jul 24, 2019 9:03 pm

it couldn't be linear if the element has 3 others attached to it

Yilun Ding
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Re: Why is AX3E2 linear?

Postby Yilun Ding » Fri Jul 26, 2019 7:54 pm

It actually a T- shaped molecule.

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