Is ICl4- Polar or Nonpolar? (And Why?)

ICl4- ion is a NONPOLAR ion.

But why? 

And how can you say that ICl4- ion is a nonpolar ion?

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

ICl4- ion is a NONPOLAR ion because all the four bonds (I-Cl bonds) are identical and ICl4- ion has symmetrical geometry which cancels out the bond polarity.

Let me explain this in detail with the help of ICl4- lewis structure and its 3D geometry.

Why is ICl4- a Nonpolar ion? (Explained in 3 Steps)

ICl4- ion is a nonpolar ion 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 ICl4- lewis structure and it contains four I-Cl bonds.

(Note: If you want to know the steps of drawing the ICl4- lewis dot structure, then visit this article: ICl4- lewis structure, Or you can also watch this short 2 minute video).

So from the above diagram we have come to know that the ICl4- ion has four I-Cl bonds.

Now in the next step we have to check whether these four I-Cl 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 ICl4- ion. It has four I-Cl bonds.

You can see the electronegativity values of Iodine (I) and Chlorine (Cl) atoms from the periodic table given below.

From the above image;

• Electronegativity of Iodine (I) = 2.66 ^[5]
• Electronegativity of Chlorine (Cl) = 3.16 ^[6]

Now let’s see the polarity of each bond.

For I-Cl bond;
The electronegativity difference (ΔEN) = 3.16 – 2.66 = 0.5
This value lies between 0.4 to 1.7, which indicates that the bond between Iodine (I) and Chlorine (Cl) is polar.
Hence, each I-Cl 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 Iodine atom (I) and partial negative charge (ẟ-) appears on the Chlorine atoms (Cl).

But wait, this alone won’t tell you whether the entire ICl4- ion is polar or nonpolar.

So let’s proceed to the next step to check the symmetry of the ICl4- ion.

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

Have a look at this 3D structure of ICl4- ion. You can see that the structure of ICl4- ion is symmetrical. 

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

As all the four bonds (I-Cl) are symmetrical and the ICl4- ion 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 ICl4- ion.

Hence, the ICl4- ion is a nonpolar ion.

I hope you have understood the reason behind the nonpolar nature of ICl4- ion.

See the polarity of other molecules to make your concepts clear:
Is XeCl2 Polar or Nonpolar?
Is AsF3 Polar or Nonpolar?
Is SCl4 Polar or Nonpolar?
Is NI3 Polar or Nonpolar?
Is IF3 Polar or Nonpolar?