Trigonal pyramidal vs. pyramidal

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Tara_Shooshani_3N
Posts: 29
Joined: Wed Sep 21, 2016 3:00 pm

Trigonal pyramidal vs. pyramidal

Postby Tara_Shooshani_3N » Tue Nov 01, 2016 4:12 pm

Are trigonal pyramidal and pyramidal the same thing? What are the bond angles?

Thanks.

Rachel_Harland_3I
Posts: 19
Joined: Fri Jul 22, 2016 3:00 am

Re: Trigonal pyramidal vs. pyramidal

Postby Rachel_Harland_3I » Tue Nov 01, 2016 4:47 pm

There is trigonal pyramidal and trigonal bipyramidal but not a separate "pyramidal." The bond angle is 106 for trigonal pyramidal and 180,90, or 120 for trigonal bipyramidal(:

Maggie Bui 1H
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Joined: Fri Jul 22, 2016 3:00 am
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Re: Trigonal pyramidal vs. pyramidal

Postby Maggie Bui 1H » Tue Nov 01, 2016 5:13 pm

Also, just a note: trigonal pyramidal is shape based on that of tetrahedral. However, while tetrahedral has four bonds attached to the central atom, trigonal pyramidal has three bonds and one lone pair attached to the central atom. Due to lone pair repulsion, the bond angle of trigonal pyramidal is slightly less than 109.5 (bond angle of tetrahedral).

Trigonal bipyramidal on the other hand is the shape that occurs when there are five bonds on the central atom - three of those bonds will form a plane which looks like the shape of trigonal planar from a bird's eye view and two of the bonds assume the axial positions (would cover up the central atom if looking at atom from overhead).


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