Bond dipole moment

Definition

A bond dipole moment is a measure of the polarity of a chemical bond within a molecule. It occurs due to the difference in electronegativity between two bonded atoms, causing a separation of electric charge.

5 Must Know Facts For Your Next Test

1. The bond dipole moment is represented by a vector pointing from the less electronegative atom to the more electronegative atom.
2. It is measured in Debye units (D).
3. The magnitude of the bond dipole moment depends on both the amount of charge separation and the distance between the charges.
4. Bond dipole moments contribute to the overall molecular dipole moment, which determines molecular polarity.
5. A zero bond dipole moment indicates that there is no difference in electronegativity between the bonded atoms.

Review Questions

• What factors determine the magnitude of a bond dipole moment?
• How does the direction of a bond dipole moment vector relate to electronegativity?
• Why might a molecule with polar bonds have an overall nonpolar character?

Related terms

Electronegativity: A measure of an atom's ability to attract and hold onto electrons within a chemical bond.

Molecular Dipole Moment: The overall polarity of a molecule resulting from vector sum of all individual bond dipoles.

Polar Covalent Bond: A type of covalent bond where electrons are shared unequally between atoms due to differences in their electronegativities.