Is O2 Polar or Nonpolar? (Why? & How?)

O2 is a NONPOLAR molecule.

But why? 

And how can you say that O2 is a nonpolar molecule?

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

O2 (or Oxygen gas) is a NONPOLAR molecule because any two bonding atoms whose electronegativity difference value is less than 0.4 forms a nonpolar bond.
Here in O2 molecule, both the atoms are Oxygen atoms. Because of this, the electronegativity difference of both the Oxygen atoms (O = 3.44) is 0 (i.e 3.44 – 3.44 = 0). This  value (0) is less than 0.4, hence the O2 molecule is a nonpolar molecule.

Didn’t understand what is written above?

Let me explain this in a short and simple way (with 3D images).
You can also watch this short 2 minute video).

Why is O2 a Nonpolar molecule? (Explained!)

O2 is a nonpolar molecule because it does not have any pole of positive charge and negative charge on it. This is because both the atoms are identical (i.e both the atoms are oxygen atoms only).

But wait, let me give you some detailed information about the nonpolar nature of O2 molecule.

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 O2 molecule.

You can see the electronegativity value of Oxygen (O) atom from the periodic table given below.

From the above image;

• Electronegativity of Oxygen (O) = 3.44 ^[5]

So for O2, the electronegativity difference (ΔEN) = 3.44 – 3.44 = 0

This value is less than 0.4, which indicates that the bond between both the Oxygen (O) atoms is nonpolar covalent bond.

Hence, O2 (or Oxygen gas) is a nonpolar molecule.

How O2 becomes a Nonpolar molecule?

In an O2 molecule, there are two Oxygen atoms (O). Both these oxygen atoms are covalently bonded with each other by sharing two electron pairs between them.

Here both the atoms are identical, so the electron pairs are equally attracted by both the oxygen atoms.

As the electron pairs are equally attracted towards both the oxygen atoms, there will not be any partial positive charge (ẟ+) or partial negative charge (ẟ-) on the Oxygen atoms (O).

And as there are no positive and negative poles of charges on the O2 molecule, it is a nonpolar molecule.

I hope you have understood the reason behind the nonpolar nature of O2 (i.e oxygen gas) molecule.

See the polarity of other molecules to make your concepts clear:
Is SF4 Polar or Nonpolar?
Is SO3 Polar or Nonpolar?
Is PCl3 Polar or Nonpolar?
Is HCN Polar or Nonpolar?
Is CH2O Polar or Nonpolar?