Is OCl2 Polar or Nonpolar? (And Why?)

OCl2 is a POLAR molecule.

But why? 

And how can you say that OCl2 is a polar molecule?

Want to know the reason?
Let’s dive into it!

OCl2 is a POLAR molecule because it has a lone pair of electrons on the Oxygen atom (O) which causes the entire molecule to bend.
This bending of OCl2 molecule results in asymmetric geometry, which makes the molecule polar.

Let me explain this in detail with the help of OCl2 lewis structure and its 3D geometry.

Why is OCl2 a Polar molecule? (Explained in 2 Steps)

To understand the polar nature of an OCl2 molecule, first of all you should know its lewis structure as well as its molecular geometry.

So let’s see this in the steps below.

Step #1: Draw the lewis structure

Here is a skeleton of OCl2 lewis structure and it contains two O-Cl bonds.

(Note: If you want to know the steps of drawing the OCl2 lewis dot structure, then visit this article: OCl2 lewis structure, Or you can also watch this short 2 minute video).

So from the above diagram we have come to know that the OCl2 molecule has two O-Cl bonds.

Now in the next step we have to check whether these two O-Cl bonds are polar or nonpolar.

And we also have to check the molecular geometry of OCl2.

Step #2: Check the bond polarity and molecular geometry

The chemical bonds can be either nonpolar, polar or ionic depending on the difference of the electronegativity values (ΔEN) between the two atoms.

Have a look at the above image.

• If the electronegativity difference (ΔEN) is less than 0.4, then the bond is nonpolar covalent bond.
• If the electronegativity difference (ΔEN) is between 0.4 to 1.7, then the bond is polar covalent bond. 
• If the electronegativity difference (ΔEN) is greater than 1.7, then the bond is an ionic bond. ^{[1] [2] [3] [4]}

Now let’s come to the example of OCl2 molecule. It has two O-Cl bonds.

You can see the electronegativity values of Oxygen (O) and Chlorine (Cl) atoms from the periodic table given below.

From the above image;

• Electronegativity of Oxygen (O) = 3.44 ^[5]
• Electronegativity of Chlorine (Cl) = 3.16 ^[6]

Now let’s see the polarity of each bond.

For O-Cl bond;
The electronegativity difference (ΔEN) = 3.44 – 3.16 = 0.28
This value is less than 0.4, which indicates that the bond between Oxygen (O) and Chlorine (Cl) is nonpolar.
Hence, each O-Cl bond is a nonpolar covalent bond.

But wait, we also have to look at the molecular geometry of OCl2 to know whether it has a symmetric shape or not.

Have a look at this 3D structure of OCl2. The Oxygen atom (O) is at the center and it is surrounded by 2 Chlorine atoms (Cl).

It also has two lone pairs on the Oxygen atom (O).

Due to the lone pairs on the oxygen atom (O), its molecular geometry becomes asymmetric.

Because of this, there are positive and negative poles of charges on the overall molecule of OCl2.

Hence, the OCl2 molecule is a polar molecule.

I hope you have understood the reason behind the polar nature of OCl2 molecule.

See the polarity of other molecules to make your concepts clear:
Is OCS Polar or Nonpolar?
Is Benzene (C6H6) Polar or Nonpolar?
Is SiH4 Polar or Nonpolar?
Is Toluene (C6H5CH3) Polar or Nonpolar?
Is PBr5 Polar or Nonpolar?