Polar Covalent Bond

Polar Covalent Bond Definition:

Polar covalent bond is a bond that is formed due to the unequal sharing of electrons between two partially charged atoms. This is observed when the difference in electronegativity between the bonding atoms is between 0.5 and 1.7.

Polar Covalent Bond Explained:

The polar covalent bond is a special case of the covalent bond where one of the atoms has a higher electronegativity than the other and exerts a pull on the bonded electrons. This gives rise to a partial negative charge on the atom with a higher electronegativity and a partial positive charge on the other atom one of the two basic types of chemical bonds in which atoms transfer electrons to each other. Notice that is different from the ionic bond in which the electrons are transferred. See Induction.

For Example – The molecule Chloromethane comprises 3 C—H bonds and 1 C—Cl bond. The electronegativity of the atoms are C =2.55, H= 2.20 and Cl = 3.16. Therefore, we note that the C–H bonds exhibit negligible polarity while the C—Cl bond will exhibit observable polarity. The Cl atom will pull the shared pair electrons with a greater force thereby giving rise to a partial negative charge on itself and a partial positive charge on the Carbon atom.

Other Examples –  The bond between Carbon and Oxygen. The electronegativity of the atoms is C = 2.55 and O = 3.44. Therefore, we note that the C–O exhibits observable polarity. The O atom will pull the shared pair electrons with greater force thereby giving rise to a partial negative charge on itself and a partial positive charge on the Carbon atom.