Is CBr4 Polar or Nonpolar? (And Why?)

CBr4 is a NONPOLAR molecule.

But why? 

And how can you say that CBr4 is a nonpolar molecule?

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

CBr4 is a NONPOLAR molecule because all the four bonds (C-Br bonds) are identical and CBr4 has symmetrical geometry which cancels out the bond polarity.

Let me explain this in detail with the help of CBr4 lewis structure and its 3D geometry.

Why is CBr4 a Nonpolar molecule? (Explained in 3 Steps)

CBr4 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 CBr4 lewis structure and it contains four C-Br bonds.

(Note: If you want to know the steps of drawing the CBr4 lewis dot structure, then visit this article: CBr4 lewis structure, Or you can also watch this short 2 minute video).

So from the above diagram we have come to know that the CBr4 molecule has four C-Br bonds.

Now in the next step we have to check whether these four C-Br 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]}

Now let’s come to the example of CBr4 molecule. It has four C-Br bonds.

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

From the above image;

• Electronegativity of Carbon (C) = 2.55 ^[5]
• Electronegativity of Bromine (Br) = 2.96 ^[6]

Now let’s see the polarity of each bond.

For C-Br bond;
The electronegativity difference (ΔEN) = 2.96 – 2.55 = 0.41
This value lies between 0.4 to 1.7, which indicates that the bond between Carbon (C) and Bromine (Br) is polar.
Hence, each C-Br 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 Bromine atoms (Br).

But wait, this alone won’t tell you whether the entire CBr4 molecule is polar or nonpolar.

So let’s proceed to the next step to check the symmetry of the CBr4 molecule.

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

Have a look at this 3D structure of CBr4. You can see that the structure of CBr4 is symmetrical. 

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

As all the four bonds (C-Br) are symmetrical and the CBr4 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 CBr4.

Hence, the CBr4 molecule is a nonpolar molecule.

I hope you have understood the reason behind the nonpolar nature of CBr4 molecule.

See the polarity of other molecules to make your concepts clear:
Is OF2 Polar or Nonpolar?
Is Ethanol (C2H5OH) Polar or Nonpolar?
Is BeCl2 Polar or Nonpolar?
Is PH3 Polar or Nonpolar?
Is NO2 Polar or Nonpolar?