ICl5 Lewis structure

ICl₅ (iodine pentachloride) has one iodine atom and five chlorine atoms.

In the ICl₅ Lewis structure, there are five single bonds around the iodine atom, with five chlorine atoms attached to it. Each chlorine atom has three lone pairs, and the iodine atom has one lone pair.

Alternative method: Lewis structure of ICl₅

Rough sketch

• First, determine the total number of valence electrons

In the periodic table, both iodine and chlorine lie in group 17.

Hence, both iodine and chlorine have seven valence electrons.

Since ICl₅ has one iodine atom and five chlorine atoms, so…

Valence electrons of one iodine atom = 7 × 1 = 7
Valence electrons of five chlorine atoms = 7 × 5 = 35

And the total valence electrons = 7 + 35 = 42

Learn how to find: Chlorine valence electrons

• Second, find the total electron pairs

We have a total of 42 valence electrons. And when we divide this value by two, we get the value of total electron pairs.

Total electron pairs = total valence electrons ÷ 2

So the total electron pairs = 42 ÷ 2 = 21

• Third, determine the central atom

We have to place the least electronegative atom at the center.

Since iodine is less electronegative than chlorine, assume that the central atom is iodine.

Therefore, place iodine in the center and chlorines on either side.

• And finally, draw the rough sketch

Lone pair

Here, we have a total of 21 electron pairs. And five I — Cl bonds are already marked. So we have to only mark the remaining sixteen electron pairs as lone pairs on the sketch.

Also remember that iodine is a period 5 element, so it can keep more than 8 electrons in its last shell. And chlorine is a period 3 element, so it can keep more than 8 electrons in its last shell.

Always start to mark the lone pairs from outside atoms. Here, the outside atoms are chlorines.

So for each chlorine, there are three lone pairs, and for iodine, there is one lone pair.

Mark the lone pairs on the sketch as follows:

Formal charge

Use the following formula to calculate the formal charges on atoms:

Formal charge = valence electrons – nonbonding electrons – ½ bonding electrons

For iodine atom, formal charge = 7 – 2 – ½ (10) = 0

For each chlorine atom, formal charge = 7 – 6 – ½ (2) = 0

Here, both iodine and chlorine atoms do not have charges, so no need to mark the charges.

Final structure

The final structure of ICl₅ includes a central iodine atom connected to five chlorine atoms through single covalent bonds. In this arrangement, the iodine atom utilizes an expanded valence shell to accommodate twelve electrons, which consist of five bonding pairs and one lone pair. Within this layout, each of the five chlorine atoms satisfies the octet rule by maintaining three lone pairs alongside its single shared bond. This arrangement represents the most stable state for the molecule because it results in a formal charge of zero for every atom involved. Thus, this specific electronic distribution serves as the definitive and most accurate Lewis representation of this molecule.

Next: SBr₂ Lewis structure

External video

• ICl5 Lewis Structure: How to Draw the Lewis Structure for ICl5 – YouTube • Wayne Breslyn

External links

• https://techiescientist.com/icl5-lewis-structure/
• https://www.thegeoexchange.org/chemistry/bonding/Lewis-Structures/ICl5-lewis-structure.html
• https://lambdageeks.com/icl5-lewis-structure/