Is SeF6 Polar or Nonpolar? (And Why?)

SeF6 is a NONPOLAR molecule.

But why? 

And how can you say that SeF6 is a nonpolar molecule?

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

SeF6 is a NONPOLAR molecule because all the six bonds (Se-F bonds) are identical and SeF6 has symmetrical geometry which cancels out the bond polarity.

Let me explain this in detail with the help of SeF6 lewis structure and its 3D geometry.

Why is SeF6 a Nonpolar molecule? (Explained in 3 Steps)

SeF6 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 SeF6 lewis structure and it contains six Se-F bonds.

(Note: If you want to know the steps of drawing the SeF6 lewis dot structure, then visit this article: SeF6 lewis structure, Or you can also watch this short 2 minute video).

So from the above diagram we have come to know that the SeF6 molecule has six Se-F bonds.

Now in the next step we have to check whether these six Se-F 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 SeF6 molecule. It has six Se-F bonds.

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

From the above image;

• Electronegativity of Selenium (Se) = 2.55 ^[6]
• Electronegativity of Fluorine (F) = 3.98 ^[7]

Now let’s see the polarity of each bond.

For Se-F bond;
The electronegativity difference (ΔEN) = 3.98 – 2.55 = 1.43
This value lies between 0.4 to 1.7, which indicates that the bond between Selenium (Se) and Fluorine (F) is polar.
Hence, each Se-F 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 Selenium atom (Se) and partial negative charge (ẟ-) appears on the Fluorine atoms (F).

But wait, this alone won’t tell you whether the entire SeF6 molecule is polar or nonpolar.

So let’s proceed to the next step to check the symmetry of the SeF6 molecule.

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

Have a look at this 3D structure of SeF6. You can see that the structure of SeF6 is symmetrical. 

The selenium atom is at the center and it is surrounded by 6 fluorine atoms which are equidistant as well as at equal angles.

As all the six bonds (Se-F) are symmetrical and the SeF6 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 SeF6.

Hence, the SeF6 molecule is a nonpolar molecule.

I hope you have understood the reason behind the nonpolar nature of SeF6 molecule.

See the polarity of other molecules to make your concepts clear:
Is ICl3 Polar or Nonpolar?
Is XeO3 Polar or Nonpolar?
Is XeO4 Polar or Nonpolar?
Is POCl3 Polar or Nonpolar?
Is H2Se Polar or Nonpolar?