Tetrahedral Atoms and Dipole Moments

[Ayesha Aslam-Mir 3C]

Will every tetrahedral molecule with different atoms around the central atom have a dipole moment? (ex: CH2Cl2)

[Varsha Ravi 3E]

I think it depends if the dipoles are canceled out.

[Kelly Ha 1K]

Yes, but I believe it also depends on the differences in electronegativity between the different atoms and the central atom. For example, if the different atoms around the central atom have the same electronegativity (despite being different elements), then there won’t be a dipole moment.

[Simrah_Ahmed1J]

Yes I think your right because you have to think about the individual dipole moments and then the net dipole moment for the molecule. So unless there are 4 of the same atoms around the central atom, there will always be a net dipole due to the differing forces since the different atoms have different electronegativities.
Reffering to the CH₂Cl₂ molecule example, I drew it in an attached image and I think we may have learned it in lecture to be a nonpolar molecule because of the opposing equal dipoles canceling, but I think that there definitely is at least a slight dipole because of how much more electronegative Cl is than H which makes the arrangement of the molecule not perfectly symmetrical. I'm not exactly sure what the verdict is on how we have to approach it for this class though so this could be a good office hours question maybe!

[Jasmine Ho 3I]

Yes, because the tetrahedral shape makes it impossible for all of the dipoles to cancel out unless all 4 are the same magnitude.

[David Jen 1J]

Dipole moments can only be cancelled out on a Tetrahedral Atom when it is four of the same elements bonded to a central element. (CCl4)

[Jaden Kwon 3C]

I think so because the dipoles wouldn't be able to cancel out due to the atoms having different electronegativities which would slightly alter bond angles and make the molecular polar.

[Javier Perez M 1H]

Dipole moments only occur when dipoles cancel out or when the forces are said to be balanced. The best way to determine if the forces are balanced around the central atom is to determine the shape and determine all forces around that central atom in the molecule.