Square planar complex vs tetrahedral complex

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Jeffrey Fenn 1G
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Square planar complex vs tetrahedral complex

Postby Jeffrey Fenn 1G » Sat Dec 12, 2020 9:29 pm

Hi, I was wondering what is the difference between a square planar complex and a tetrahedral complex. I know they both have 4 ligands attached to the central atom, but what makes them different?

Sunny Wu 3A
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Re: Square planar complex vs tetrahedral complex

Postby Sunny Wu 3A » Sat Dec 12, 2020 9:32 pm

A square planar structure has 2 lone pairs on the central atom (AX4E2) while a tetrahedral structure has no lone pairs on the central atom (AX4). The bond angles of a square planar structure are 90 degrees vs 109.5 degrees for tetrahedral.

EDIT: misread your question, my apologies! Please ignore what I said and refer to the comments below.
Last edited by Sunny Wu 3A on Sat Dec 12, 2020 10:48 pm, edited 2 times in total.

tamara masri_3D
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Re: Square planar complex vs tetrahedral complex

Postby tamara masri_3D » Sat Dec 12, 2020 9:35 pm

I'm not 1000% sure how it relates to ligands, but I know that square planar shape generally occurs when there are 2 lateral lone pairs and 4 equatorial bonding pairs for an atom. This would be an octahedral electron geometry but with 2 lone pairs. Tetrahedral geometry occurs when there are 4 regions of electron density. I don't think we have to know the difference for ligand structures, other than 4 bonds can be either square planar or tetrahedral. Hope this helps

Andrew Dao 3C
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Re: Square planar complex vs tetrahedral complex

Postby Andrew Dao 3C » Sat Dec 12, 2020 9:38 pm

Usually the molecules that are tetrahedral involve an atom that makes 4 bonds and has no lone pairs. For example, Carbon Tetrachloride (CCl4) involves a carbon in the center surrounded by the 4 chlorine atoms. Since carbon makes 4 bonds and has no extra lone pairs, the shape is tetrahedral for maximum distance between electrons shared. On the other hand, a square planar involves a center atom that makes 4 bonds but also has 2 extra lone pairs (4 electrons). This rest on the top and bottom, while the 4 bonded atoms make a square shape around the center atom, hence the name. For example, Xenon Tetrafluoride (XeF4). The square planar name comes from the fact that VSEPR ignores lone pairs in naming shapes, even if they affect the shape.

Nancy Yao
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Re: Square planar complex vs tetrahedral complex

Postby Nancy Yao » Wed Dec 16, 2020 6:03 am

Tetrahedral is represented as AX4, while square planar is AX4E2, as square planar has two more electron domains. Prof Lavelle said this shape is not common at all, like XeF4, but in Sapling it says square planar is a common shape. This is why I am confused.
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Andy Hernandez
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Re: Square planar complex vs tetrahedral complex

Postby Andy Hernandez » Wed Dec 16, 2020 10:19 pm

Tetrahedral is AX4. Square planar is AX4E2

Gustavo_Chavez_1K
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Re: Square planar complex vs tetrahedral complex

Postby Gustavo_Chavez_1K » Wed Dec 16, 2020 11:31 pm

Yeah so the only difference is that the tetrahedral complex has four bonds so it is attached to four ligands, while the square planar has only 3 bonds and a lone pair of electrons which counts as the fourth region of electron density.


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