Molecular Shape of BF3: Trigonal Planar or Pyramidal?

[daphnelee-mh]

Homework Statement

Experiment confirms the polarity of the molecule of formula BY3. Which molecular shapes are possible and which impossible for BY3?

Relevant Equations

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Answer given is " The molecule could be trigonal pyramidal or T shaped, but could not be trigonal planar."

I am confused as the shape of BF3 is trigonal planar...

 

[Borek]

I suppose Y in the BY₃ is intended to mean "some particular element", not "every possible element". In other words, question asks about possible shape of a specific molecule for which we know it is polar, not for a shape of every existing molecule - as not all of them will be identical (some will be polar, some will be not polar).

 

[epenguin]

Homework Statement:: Experiment confirms the polarity of the molecule of formula BY3. Which molecular shapes are possible and which impossible for BY3?
Homework Equations:: -

Answer given is " The molecule could be trigonal pyramidal or T shaped, but could not be trigonal planar."

I am confused as the shape of BF3 is trigonal planar...

Maybe they mean trigonal planar is not polar in the way BY₃ is when B is not in the same plane as the Y's?

 

[jim mcnamara]

It is hard to know exactly what Y represents. Is there part of the problem statement not shown in the question?

 

[daphnelee-mh]

No, just written as this

 

[TeethWhitener]

Experiment confirms the polarity of the molecule of formula BY3.

snip

I am confused as the shape of BF3 is trigonal planar...

Is BF₃ polar?

 

[daphnelee-mh]

Nonpolar, maybe I misunderstood the meaning, as I thought " confirms the polarity " may be polar or nonpolar

 

[Dr_Nate]

I can guarantee you that Y means "unspecified element" as others have mentioned.

"Confirms the polarity..." is actually poor wording. You should read it as "confirms it is a polar molecule".