Intermolecular forces in BF3

Feb 2015
1
0
Hi!

Boron trifluoride is a nonpolar molecule due to its high symmetry even though the covalent bonds within the molecule are polar. As a result, the only type of intermolecular forces in BF3 would be the London dispersion forces. I understand that these forces are exhibited by nonpolar molecules because of the correlated movements of the electrons in interacting molecules. Because the electrons in adjacent molecules "flee" as they repel each other, electron density in a molecule becomes redistributed in proximity to another molecule and this results in the creation of a temporary dipole moment in the molecule.

However, the boron atom in BF3 is still a partially positive center and the fluorine atoms represent partially negative ends. Wouldn't it make sense that this partially positive center of one BF3 molecule would attract at least one of the partially negative fluorine ends in another BF3 molecule? If yes, then this type of intermolecular forces would resemble (but not identical, by definition, to) the permanent dipole-dipole forces in water. In other words, the cause of these intermolecular forces is not an induced temporary dipole in neighboring molecules.

Any contribution is appreciated.