The direction of dipole moment is from negative to positive charge.
- A dipole moment arises in any system in which there is a separation of charge. They can, therefore, arise in ionic bonds as well as in covalent bonds.
- Dipole moments occur due to the difference in electronegativity between two chemically bonded atoms.
- A bond dipole moment is a measure of the polarity of a chemical bond between two atoms in a molecule.
- It involves the concept of electric dipole moment, which is a measure of the separation of negative and positive charges in a system.
- It can be noted that the symbols 𝛿+ and 𝛿– represent the two electric charges that arise in a molecule which are equal in magnitude but are of opposite signs.
- They are separated by a set distance, which is commonly denoted by d.
Dipole moment of H2O
Since the oxygen atom is much more electronegative than the hydrogen atom, the electrons in a water molecule group around it. The existence of a lone pair of electrons in the oxygen atom, on the other hand, causes the water molecule to bend.
The bond angle in a water molecule is 104.5o. The individual bond moment of an oxygen-hydrogen bond is 1.5 D. The net dipole moment in a water molecule is found to be 1.84D.