NH3 has a dipole moment of 1.4D.
What is dipole moment?
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. The bond dipole moment is a vector quantity since it has both magnitude and direction.
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 in NH3
Ammonia is a colourless gas with a chemical formula NH3.
It consists of hydrogen and nitrogen. In its aqueous form, it is called ammonium hydroxide. This inorganic compound has a pungent smell. In its concentrated form, it is dangerous and caustic.
In NH3, we know nitrogen is more electronegative than hydrogen, so the dipole moment is from H to N. The net dipole moment of three N- H bonds will add up to give 1.4D.