Question #e9eb6

1 Answer
Sep 19, 2017

Diborane is nonpolar because it is a symmetrical molecule.

Explanation:

The structure of diborane is

Diborane

Two of the "H" atoms act as bridges between the "B" atoms.

Theoretical calculations show that the partial charges on each atom are:

  • "B" color(white)(mmmmll)= "+2.12"
  • "Bridging H" = color(white)(ll)"-0.71"
  • "Terminal H" = color(white)(l) "-0.70"

Thus, there are fairly large "B-H" bond dipoles.

However, the diborane molecule is perfectly symmetrical.

Every "B-H" bond dipole that points in one direction has a counterpart that points in exactly the opposite direction.

Thus, all bond dipoles cancel and diborane is a nonpolar molecule.