Is C2Cl4 Polar or Nonpolar? (And Why?)

C2Cl4 is a NONPOLAR molecule.

But why? 

And how can you say that C2Cl4 is a nonpolar molecule?

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

C2Cl4 is a NONPOLAR molecule because the outer bonds (C-Cl bonds) are identical and C2Cl4 has symmetrical geometry which cancels out the bond polarity.

Let me explain this in detail with the help of C2Cl4 lewis structure and its 3D geometry.

Why is C2Cl4 a Nonpolar molecule? (Explained in 2 Steps)

C2Cl4 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 just 2 steps!

Step #1: Draw the lewis structure

Here is a skeleton of C2Cl4 lewis structure and it contains one C=C bond and four C-Cl bonds.

So from the above diagram we have come to know that the C2Cl4 molecule has one C=C bond and four C-Cl bonds.

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

And we also have to check the molecular geometry of C2Cl4.

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 C2Cl4 molecule. It has C=C bond as well as C-Cl bonds.

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

From the above image;

• Electronegativity of Carbon (C) = 2.55 ^[6]
• Electronegativity of Chlorine (Cl) = 3.16 ^[7]

Now let’s see the polarity of each bond.

For Carbon-Carbon bond;
The electronegativity difference (ΔEN) = 2.55 – 2.55 = 0 
This value is less than 0.4, which indicates that the C=C is nonpolar.
Hence, the C=C bond is a nonpolar covalent bond.

For C-Cl bond;
The electronegativity difference (ΔEN) = 3.16 – 2.55 = 0.61
This value lies between 0.4 to 1.7, which indicates that the bond between Carbon (C) and Chlorine (Cl) is polar.
Hence, each C-Cl 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 atoms (C) and partial negative charge (ẟ-) appears on the Chlorine atoms (Cl).

But wait, this alone won’t tell you whether the entire C2Cl4 molecule is polar or nonpolar.

So let’s proceed to the next step to check the symmetry of the C2Cl4 molecule.

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

Have a look at this 3D structure of C2Cl4. You can see that the structure of C2Cl4 is symmetrical. 

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

As all the four bonds (C-Cl) are symmetrical and the C2Cl4 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 C2Cl4.

Hence, the C2Cl4 molecule is a nonpolar molecule.

I hope you have understood the reason behind the nonpolar nature of C2Cl4 molecule.

See the polarity of other molecules to make your concepts clear:
Is BeBr2 Polar or Nonpolar?
Is AsCl3 Polar or Nonpolar?
Is N2H2 Polar or Nonpolar?
Is SbF5 Polar or Nonpolar?
Is HOCl Polar or Nonpolar?