Is SF6 Polar or Nonpolar? (And Why?)

SF6 is a NONPOLAR molecule.

But why? 

And how can you say that SF6 is a nonpolar molecule?

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

SF6 is a NONPOLAR molecule because all the six bonds (S-F bonds) are identical and SF6 has symmetrical geometry which cancels out the bond polarity.

Let me explain this in detail with the help of SF6 lewis structure and its 3D geometry.

Why is SF6 a Nonpolar molecule? (Explained in 3 Steps)

SF6 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 SF6 lewis structure and it contains six S-F bonds.

(Note: If you want to know the steps of drawing the SF6 lewis dot structure, then visit this article: SF6 lewis structure, Or you can also watch this short 2 minute video).

So from the above diagram we have come to know that the SF6 molecule has six S-F bonds.

Now in the next step we have to check whether these six S-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 SF6 molecule. It has six S-F bonds.

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

From the above image;

• Electronegativity of Sulfur (S) = 2.58 ^[6]
• Electronegativity of Fluorine (F) = 3.98 ^[7]

Now let’s see the polarity of each bond.

For S-F bond;
The electronegativity difference (ΔEN) = 3.98 – 2.58 = 1.4
This value lies between 0.4 to 1.7, which indicates that the bond between Sulfur (S) and Fluorine (F) is polar.
Hence, each S-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 Sulfur atom (S) and partial negative charge (ẟ-) appears on the Fluorine atoms (F).

But wait, this alone won’t tell you whether the entire SF6 molecule is polar or nonpolar.

So let’s proceed to the next step to check the symmetry of the SF6 molecule.

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

Have a look at this 3D structure of SF6. You can see that the structure of SF6 is symmetrical. 

The sulfur 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 (S-F) are symmetrical and the SF6 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 SF6.

Hence, the SF6 molecule is a nonpolar molecule.

I hope you have understood the reason behind the nonpolar nature of SF6 molecule.

See the polarity of other molecules to make your concepts clear:
Is BCl3 Polar or Nonpolar?
Is CHCl3 Polar or Nonpolar?
Is NF3 Polar or Nonpolar?
Is CH3OH (Methanol) Polar or Nonpolar?
Is SCl2 Polar or Nonpolar?