Is CO2 Polar or Nonpolar? (And Why?)

CO2 (Carbon dioxide) is a NONPOLAR molecule.

But why? 

And how can you say that CO2 is a nonpolar molecule?

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

CO2 (or Carbon dioxide) is a NONPOLAR molecule because both the bonds (C=O bonds) are identical and CO2 has symmetrical geometry which cancels out the bond polarity.

Let me explain this in detail with the help of CO2 lewis structure and its 3D geometry.

Why is CO2 a Nonpolar molecule? (Explained in 3 Steps)

CO2 is a nonpolar molecule because it does not have any pole of positive charge and negative charge on it.

Let me explain this to you in 3 steps!

Step #1: Draw the lewis structure

Here is a skeleton of CO2 lewis structure and it contains two C=O bonds.

(Note: If you want to know the steps of drawing the CO2 lewis dot structure, then visit this article: CO2 lewis structure, Or you can also watch this short 2 minute video).

So from the above diagram we have come to know that the CO2 molecule has two C=O bonds.

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

Step #2: Check whether individual bonds are polar or nonpolar

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] [5]}

Now let’s come to the example of CO2 molecule. It has two C=O bonds.

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

From the above image;

• Electronegativity of Carbon (C) = 2.55 ^[6]
• Electronegativity of Oxygen (O) = 3.44 ^[7]

Now let’s see the polarity of each bond.

For Carbon-Oxygen bond;
The electronegativity difference (ΔEN) = 3.44 – 2.55 = 0.89
This value lies between 0.4 to 1.7, which indicates that the bond between Carbon (C) and Oxygen (O) is polar.
Hence, each Carbon-Oxygen bond is a polar covalent bond.

You can see in the above image that because of electronegativity difference, the partial positive charge (ẟ+) appears on the Carbon atom (C) and partial negative charge (ẟ-) appears on the Oxygen atoms (O).

But wait, this alone won’t tell you whether the entire CO2 molecule is polar or nonpolar.

So let’s proceed to the next step to check the symmetry of the CO2 molecule.

Step #3: Check whether the molecule is symmetric or not

Have a look at this 3D structure of CO2. You can see that the structure of CO2 is symmetrical. 

The carbon atom is at the center and it is surrounded by 2 oxygen atoms which are equidistant as well as at equal angles.

As both the bonds (C=O) are symmetrical and the CO2 molecule has a symmetrical geometry, their bond polarity gets canceled with each other.

Because of this, there are no positive and negative poles of charges on the overall molecule of CO2.

Hence, the CO2 molecule is a nonpolar molecule.

I hope you have understood the reason behind the nonpolar nature of CO2 molecule.

See the polarity of other molecules to make your concepts clear:
Is CCl4 Polar or Nonpolar?
Is CH4 (Methane) Polar or Nonpolar?
Is H2O (Water) Polar or Nonpolar?
Is SO2 Polar or Nonpolar?
Is CS2 Polar or Nonpolar?