Tetrahedral versus Trigonal Pyramidal

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

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Amy Lefley 1J
Posts: 60
Joined: Fri Sep 28, 2018 12:15 am

Tetrahedral versus Trigonal Pyramidal

Postby Amy Lefley 1J » Mon Nov 12, 2018 10:51 pm

Why does a tetrahedral have bond angles of 109.5 degrees while a trigonal pyramidal have bond angles of less than 109.5 degrees. Is it because the lone pair on the trigonal pyramidal is closer to the central atom and pushes the other atoms closer together?

Yukta Italia 3I
Posts: 31
Joined: Fri Sep 28, 2018 12:24 am

Re: Tetrahedral versus Trigonal Pyramidal

Postby Yukta Italia 3I » Mon Nov 12, 2018 11:15 pm

Amy Lefley 1K wrote:Why does a tetrahedral have bond angles of 109.5 degrees while a trigonal pyramidal have bond angles of less than 109.5 degrees. Is it because the lone pair on the trigonal pyramidal is closer to the central atom and pushes the other atoms closer together?

Yep it's because the lone pair repels the other bonds.

Ethan Breaux 2F
Posts: 63
Joined: Sat Sep 29, 2018 12:16 am

Re: Tetrahedral versus Trigonal Pyramidal

Postby Ethan Breaux 2F » Tue Nov 13, 2018 2:12 am

Also it's important to know that lone pairs have stronger repelling forces than bond pairs.

Christopher Wendland 4F
Posts: 30
Joined: Fri Sep 28, 2018 12:29 am

Re: Tetrahedral versus Trigonal Pyramidal

Postby Christopher Wendland 4F » Tue Nov 13, 2018 11:26 am

Lone pairs have a stronger repelling force than normal bonds, therefore the angle becomes about 2.5 degrees less than what it would have been if the lone pair is replaced with a normal bond.


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