BF3(bromine trifluoride) is an inorganic tetra-atomic chemical compound that does not have a dipole moment (dipole moment is zero). This is because of the spatial arrangement of the B-F bonds in the molecule and the overall shape of the molecule.
Dipole moment is the measure of net polarity of a molecule, which is given by the magnitude of the charge (Q) at either end of the molecular dipole multiplied by the distance (r) between the charges.
Dipole Moment = Q x r
Dipole talks more about the charge separation in a molecule. The larger the electronegativity difference between the bonded atoms, the larger the dipole moment. BF 3 molecule assumes a trigonal planar shape. The B-F bonds are polar and are symmetrically arranged around the central boron atom. They are subsequently oriented at an angle of 120 degrees to one another and all the bonds lie in one plane.
Additionally each B-F bond has a dipole moment with a perfect balance of the partial negative charges on the fluorine atoms and partial positive charges on the boron atoms. This results in the cancellation of the dipole moments of each of the bonds, bringing the Net Dipole Moment to 0.
The knowledge of dipole moment is important for the following reasons:
- Helps to clearly distinguish between a polar molecule and a non-polar molecule.
- Helps to accurately determine the shape of the various molecules.
- Helps to determine the degree of polarity in a diatomic molecule.