Is BrF5 Polar or Nonpolar? (And Why?)

BrF5 is a POLAR molecule.

But why? 

And how can you say that BrF5 is a polar molecule?

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

BrF5 is a POLAR molecule because the Br-F bonds present in the molecule are polar and it has asymmetric geometry which causes the partial positive (ẟ+) and partial negative (ẟ-) charge to appear on the molecule. These ẟ+ and ẟ- charges are responsible to make the entire BrF5 molecule polar.

Let me explain this in detail with the help of BrF5 lewis structure and its 3D geometry.

Why is BrF5 a Polar molecule? (Explained in 3 Steps)

BrF5 is a polar molecule because it has poles of partial positive charge (ẟ+) and partial negative charge (ẟ-) on it.

Let me explain this to you in 3 steps!

Step #1: Draw the lewis structure

Here is a skeleton of BrF5 lewis structure and it contains five Br-F bonds.

(Note: If you want to know the steps of drawing the BrF5 lewis dot structure, then visit this article: BrF5 lewis structure, Or you can also watch this short 2 minute video).

So from the above diagram we have come to know that the BrF5 molecule has five Br-F bonds.

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

And we also have to check the molecular geometry of BrF5.

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 BrF5 molecule. It has five Br-F bonds.

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

From the above image;

• Electronegativity of Bromine (Br) = 2.96 ^[5]
• Electronegativity of Fluorine (F) = 3.98 ^[6]

Now let’s see the polarity of each bond.

For Br-F bond;
The electronegativity difference (ΔEN) = 3.98 – 2.96 = 1.02
This value lies between 0.4 to 1.7, which indicates that the bond between Bromine (Br) and Fluorine (F) is polar.
Hence, the Br-F bonds are polar covalent bond.

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

But wait, we also have to look at the molecular geometry of BrF5 to know whether it has a symmetric shape or not.

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

Have a look at this 3D structure of BrF5. The Bromine atom (Br) is at the center and it is surrounded by 5 Fluorine atoms (F).

It also has one lone pair on the Bromine atom (Br).

Due to the lone pair on the bromine atom (Br), its molecular geometry becomes asymmetric.

Because of this, there are positive and negative poles of charges on the overall molecule of BrF5.

Hence, the BrF5 molecule is a polar molecule.

I hope you have understood the reason behind the polar nature of BrF5 molecule.

See the polarity of other molecules to make your concepts clear:
Is C2H2 Polar or Nonpolar?
Is NCl3 Polar or Nonpolar?
Is SF2 Polar or Nonpolar?
Is C2H4 Polar or Nonpolar?
Is XeF2 Polar or Nonpolar?