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chemistry bond shapes and angles

Why in BrF3 does it have a T shape with lone pairs 120 degrees from each other in the middle, when surely they could be 180 degrees from each other above and below Br to form a trigonal planar shape
the electron pairs repel each other with the same amount of force so they all have to have the same angle. If it's planar then 360/3 = 120 between the Flourines
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It says in the textbook the fluorines are 86 degrees as both the lone pairs are 120 degrees apart , but i don't understand why the lone pairs dont go directly above and below to be 180 degrees apart and have the fluorines in a trigonal planar
Boron triflouride (BF3) is trigonal planar so the shared electron pairs are 120 degrees away from each other according to the repulsion theory, if it was linear the bonded electrons would be 180 degrees from each other like CO2 also there aren't any lone pairs in BF3.
(edited 6 years ago)
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Original post by lmaooome
Boron triflouride (BF3) is trigonal planar so the shared electron pairs are 120 degrees away from each other according to the repulsion theory, if it was linear the bonded electrons would be 180 degrees from each other like CO2 also there aren't any lone pairs in BF3.


It was BrF3 not BF3, sorry to confuse it all
Original post by number0
Why in BrF3 does it have a T shape with lone pairs 120 degrees from each other in the middle, when surely they could be 180 degrees from each other above and below Br to form a trigonal planar shape


Isn't it because lone pairs cause more repulsion than bonded electron pairs
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Original post by lmaooome
Then surely its v shaped/bent if it occupies 2 lone pairs making the bond angles 104.5 degrees away from each other


It has that expanded octet form so more than 8 electrons around central atom, so it has 3 covalent bonds and 2 lone pairs
Original post by number0
It has that expanded octet form so more than 8 electrons around central atom, so it has 3 covalent bonds and 2 lone pairs


Yep, my mistake i forgot that Br was in period 4.
Original post by number0
Why in BrF3 does it have a T shape with lone pairs 120 degrees from each other in the middle, when surely they could be 180 degrees from each other above and below Br to form a trigonal planar shape


It is 120 and 90 degrees apart because the molecule is bent, it has to do with the interaction of the different p molecular orbitals. similar to how water is a bent molecule, you could argue that the lone pairs could go on either side and the bond angle would be 180 making it a linear molecule.
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Original post by sophe1216
It is 120 and 90 degrees apart because the molecule is bent, it has to do with the interaction of the different p molecular orbitals. similar to how water is a bent molecule, you could argue that the lone pairs could go on either side and the bond angle would be 180 making it a linear molecule.


The textbook shows it as T shaped with bond angles of 86 degrees due to the position of the lone pairs
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Anyone know, still confused by why the lone pairs do this instead of being 180 degrees from each other??

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