H2CBr2 Polarity

[Kim]

Why is H2CBr2 polar? Wouldn't the 2 Br cancel and the 2 H cancel?

[Roline Dahi 1J]

Tetrahedral molecules are only nonpolar when all four atoms bound to the central atom are the exact same (must be identical)

[Jenna_Hakel_2A]

Following on the above comment, if you look at the shape of a tetrahedral molecule, none of the atoms connected to the central atom are completely opposite each other. The bond angle is 109.5 for every bond, never 180. Because of this, even if the atoms appear to be directly across from each other in a Lewis diagram, in the tetrahedral shape, they will still be slightly pointed in the same direction. Therefore, even though there are 2 pairs of identical atoms, each pair will still contribute to a dipole moment in one direction, as they cannot be directly apart from one another.