Can someone please explain to me how SeF4 is polar?
I've already drawn the VSEPR model and I see no lone pairs, and the electrons cancel each other out. So why is this molecule polar?
Actualizar:EDIT: Oh my God, yes! I looked at my structure once again and found that I counted the number of pairs wrong. I left out one more pair! And since selenium can occupy more than 8 electrons, I can simply add the last pair next to it and that would make it polar. Thank you!
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Verified answer
Se has 6 valence electrons. 4 will be used to bond with the 4 F's. That leaves 2, which will form 1 lone pair of electrons.
The whole geometry (including the lone pair) is trigonal bipyramidal. The lone pair will occupy one of the equatorial positions.
This will make the molecular geometry a see-saw shape. The 4 Se-F bonds are NOT arranged symmetry, so their polarities will NOT cancel each other out. This is what makes the molecular polar.
It does have a lone pair, maybe that's where you went wrong. (You'd be right about it being apolar if it was a linear molecule, but it's not )
Having that in mind, i'm sure you can easily realize why it is polar. Might be easier to visualize if you google the 3d structure of the molecule
this is hard to explain , but ill do my best .
SeF4 - when you draw it out, Se will be in the middle. The 4 F's will be around. So it's equal - do you get it?
nonpolar would be SeF3 or SeF2.
sorry if you dont get it; but this is how my teacher taught me and i cant really explain it. ):
best of luck!