Is CS2 Polar or Nonpolar? (And Why?)

CS2 is a NONPOLAR molecule.

But why? 

And how can you say that CS2 is a nonpolar molecule?

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

CS2 is a NONPOLAR molecule because both the bonds (C=S bonds) are identical and CS2 has symmetrical geometry which cancels out the bond polarity.

Let me explain this in detail with the help of CS2 lewis structure and its 3D geometry.

Why is CS2 a Nonpolar molecule? (Explained in 2 Steps)

CS2 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 2 steps!

Step #1: Draw the lewis structure

Here is a skeleton of CS2 lewis structure and it contains two C=S bonds.

(Note: If you want to know the steps of drawing the CS2 lewis dot structure, then visit this article: CS2 lewis structure, Or you can also watch this short 2 minute video).

So from the above diagram we have come to know that the CS2 molecule has two C=S bonds.

Now in the next step we have to check whether these two C=S 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 CS2 molecule. It has two C=S bonds.

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

From the above image;

• Electronegativity of Carbon (C) = 2.55 ^[6]
• Electronegativity of Sulfur (S) = 2.58 ^[7]

Now let’s see the polarity of each bond.

For Carbon-Sulfur bond;
The electronegativity difference (ΔEN) = 2.58 – 2.55 = 0.03
This value is less than 0.4, which indicates that the bond between Carbon (C) and Sulfur (S) is nonpolar.
Hence, each C=S bond is a nonpolar covalent bond.

As each C=S bonds are nonpolar, there will not be any partial positive charge (ẟ+) or partial negative charge (ẟ-) on the carbon and hydrogen atoms.

From this, you can easily get the idea that the CS2 molecule is a nonpolar molecule.

But let’s also see whether this CS2 molecule has a symmetric geometry or not.

Have a look at this 3D structure of CS2. You can see that the structure of CS2 is symmetrical. 

The carbon atom is at the center and it is surrounded by 4 hydrogen atoms which are equidistant as well as at equal angles.

As both the bonds (C=S) are nonpolar and the CS2 molecule has a symmetrical geometry, there are no positive and negative poles of charges on the overall molecule of CS2.

Hence, the CS2 molecule is a nonpolar molecule.

I hope you have understood the reason behind the nonpolar nature of CS2 molecule.

See the polarity of other molecules to make your concepts clear:
Is Hydrogen Chloride (HCl) Polar or Nonpolar?
Is BF3 Polar or Nonpolar?
Is H2S Polar or Nonpolar?
Is CH3Cl Polar or Nonpolar?
Is CF4 Polar or Nonpolar?