The dipole moment of BF₃ is zero because

The BF3 dipole moment is zero due to the molecule's unique structure and symmetry. Boron trifluoride (BF3) has a trigonal planar geometry, where the boron atom is at the center, and the three fluorine atoms are positioned at 120° angles to each other. This symmetrical arrangement plays a key role in the molecule's overall dipole moment.

In a trigonal planar structure, each B−F bond creates a dipole moment. However, because the BF3 dipole moment depends on both the magnitude and direction of these dipoles, the symmetry of the molecule comes into play. The three B−F bond dipoles are of equal magnitude, but they are arranged in such a way that the dipoles point in directions that are opposite to each other. This leads to a cancellation of the individual dipole moments.

The result is that the vector sum of all the dipole moments in the BF3 dipole moment calculation equals zero. As a result, the molecule does not exhibit any overall dipole moment, and thus it is considered non-polar. Despite having polar bonds (due to the electronegativity difference between boron and fluorine), the symmetrical structure ensures that the net dipole moment of BF3 is zero.