Is BBr3 Polar or Nonpolar? (And Why?)

Is BBr3 Polar or Nonpolar

BBr3 is a NONPOLAR molecule.

But why? 

And how can you say that BBr3 is a nonpolar molecule?

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

BBr3 is a NONPOLAR molecule because all the three bonds (B-Br bonds) are identical and BBr3 has symmetrical geometry which cancels out the bond polarity.

Let me explain this in detail with the help of BBr3 lewis structure and its 3D geometry.

Why is BBr3 a Nonpolar molecule? (Explained in 3 Steps)

BBr3 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 BBr3 lewis structure and it contains three B-Br bonds.

Is BBr3 Polar or Nonpolar

(Note: If you want to know the steps of drawing the BBr3 lewis dot structure, then visit this article: BBr3 lewis structure, Or you can also watch this short 2 minute video).

So from the above diagram we have come to know that the BBr3 molecule has three B-Br bonds.

Now in the next step we have to check whether these three B-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 BBr3 molecule. It has three B-Br bonds.

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

From the above image;

  • Electronegativity of Boron (B) = 2.04 [5]
  • Electronegativity of Bromine (Br) = 2.96 [6]

Now let’s see the polarity of each bond.

For B-Br bond;
The electronegativity difference (ΔEN) = 2.96 – 2.04 = 0.92
This value lies between 0.4 to 1.7, which indicates that the bond between Boron (B) and Bromine (Br) is polar.
Hence, each B-Br bond is a polar covalent bond.

Is BBr3 Polar or Nonpolar

You can see in the above image that because of electronegativity difference, the partial positive charge (ẟ+) appears on the Boron atom (B) and partial negative charge (ẟ-) appears on the Bromine atoms (Br).

But wait, this alone won’t tell you whether the entire BBr3 molecule is polar or nonpolar.

So let’s proceed to the next step to check the symmetry of the BBr3 molecule.

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

Have a look at this 3D structure of BBr3. You can see that the structure of BBr3 is symmetrical. 

The boron atom is at the center and it is surrounded by 3 bromine atoms which are equidistant as well as at equal angles.

Is BBr3 Polar or Nonpolar

As all the three bonds (B-Br) are symmetrical and the BBr3 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 BBr3.

Hence, the BBr3 molecule is a nonpolar molecule.

I hope you have understood the reason behind the nonpolar nature of BBr3 molecule.

See the polarity of other molecules to make your concepts clear:
Is BeH2 Polar or Nonpolar?
Is Cyclohexane (C6H12) Polar or Nonpolar?
Is IOF5 Polar or Nonpolar?
Is NH2Cl Polar or Nonpolar?
Is HNO3 Polar or Nonpolar? 


Jay is an educator and has helped more than 100,000 students in their studies by providing simple and easy explanations on different science-related topics. With a desire to make learning accessible for everyone, he founded Knords Learning, an online learning platform that provides students with easily understandable explanations.

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