Trigonal Pyramid vs Trigonal Planar

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

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Bao Tram Nguyen
Posts: 35
Joined: Sat Aug 24, 2019 12:17 am

Trigonal Pyramid vs Trigonal Planar

Postby Bao Tram Nguyen » Thu Nov 14, 2019 7:14 pm

Is there a difference between these two shapes and if you were to put one or the other on the exam, would it affect our grade?

Kavee Dodampahala 4E
Posts: 51
Joined: Sat Jul 20, 2019 12:17 am

Re: Trigonal Pyramid vs Trigonal Planar

Postby Kavee Dodampahala 4E » Thu Nov 14, 2019 7:37 pm

Trigonal planar has just three areas of electron density. Trigonal pyramidal has four areas of electron density, one of those areas being a lone pair.

Anthony Hatashita 4H
Posts: 103
Joined: Wed Sep 18, 2019 12:21 am

Re: Trigonal Pyramid vs Trigonal Planar

Postby Anthony Hatashita 4H » Thu Nov 14, 2019 7:38 pm

If there is a lone pair on the central atom, it makes the overall shape trigonal pyramidal, if there are no lone pairs on the central atom it's planar pretty sure.

Michelle Xie 2B
Posts: 99
Joined: Sat Aug 17, 2019 12:18 am

Re: Trigonal Pyramid vs Trigonal Planar

Postby Michelle Xie 2B » Thu Nov 14, 2019 7:46 pm

Trigonal planar is in one plane and has three areas of e density while trigonal pyramidal is 3d and has 4 areas.

Claire Lo 3C
Posts: 55
Joined: Sat Aug 17, 2019 12:18 am

Re: Trigonal Pyramid vs Trigonal Planar

Postby Claire Lo 3C » Thu Nov 14, 2019 8:16 pm

Also the bond angle is different. Trigonal planar has bond angles of 120 while trigonal pyramidal has bond angles of around 107, so these two are absolutely different.

RRahimtoola1I
Posts: 102
Joined: Fri Aug 09, 2019 12:15 am

Re: Trigonal Pyramid vs Trigonal Planar

Postby RRahimtoola1I » Sat Nov 16, 2019 2:51 pm

They are two completely different shapes. Trigonal planar has no lone pairs and 3 bonded pairs while trigonal pyramidal has 1 lone pair and 3 bonded pairs.

Patricia Chan 1C
Posts: 50
Joined: Sat Jul 20, 2019 12:16 am

Re: Trigonal Pyramid vs Trigonal Planar

Postby Patricia Chan 1C » Sat Nov 16, 2019 2:55 pm

They are different shapes! Trigonal planar has three regions of electron density, all being bonded pairs. Trigonal pyramidal has four regions of electron density, but with three bonded pairs and one lone pair. Hope this helps!


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