IOF5 Lewis structure

IOF5 Lewis Structure
IOF5 Lewis structure | Image: Learnool

IOF5 has one iodine atom, one oxygen atom, and five fluorine atoms.

In IOF5 Lewis structure, there is one double bond and five single bonds around the iodine atom, with one oxygen atom and five fluorine atoms attached to it. Each fluorine atom has three lone pairs, and the oxygen atom has two lone pairs.

Rough sketch

  • First, determine the total number of valence electrons
Periodic table | Image: Learnool

In the periodic table, both iodine and fluorine lie in group 17, and oxygen lies in group 16.

Hence, both iodine and fluorine have seven valence electrons, and oxygen has six valence electrons.

Since IOF5 has one iodine atom, one oxygen atom, and five fluorine atoms, so…

Valence electrons of one iodine atom = 7 × 1 = 7
Valence electrons of one oxygen atom = 6 × 1 = 6
Valence electrons of five fluorine atoms = 7 × 5 = 35

And the total valence electrons = 7 + 6 + 35 = 48

  • Second, find the total electron pairs

We have a total of 48 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 = 48 ÷ 2 = 24

  • Third, determine the central atom

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

Since iodine is less electronegative than oxygen and fluorine, assume that the central atom is iodine.

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

  • And finally, draw the rough sketch
IOF5 Lewis Structure (Step 1)
Rough sketch of IOF5 Lewis structure | Image: Learnool

Lone pair

Here, we have a total of 24 electron pairs. And six bonds are already marked. So we have to only mark the remaining eighteen 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 both (oxygen and fluorine) are the period 2 elements, so they can not keep more than 8 electrons in their last shell.

Always start to mark the lone pairs from outside atoms. Here, the outside atoms are oxygen and fluorines.

So for oxygen and each fluorine, there are three lone pairs, and for iodine, there is zero lone pair because all eighteen electron pairs are over.

Mark the lone pairs on the sketch as follows:

IOF5 Lewis Structure (Step 2)
Lone pairs marked on IOF5 Lewis structure | Image: Learnool

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 – 0 – ½ (12) = +1

For oxygen atom, formal charge = 6 – 6 – ½ (2) = -1

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

Here, both iodine and oxygen atoms have charges, so mark them on the sketch as follows:

IOF5 Lewis Structure (Step 3)
Formal charges marked on IOF5 Lewis structure | Image: Learnool

The above structure is not a stable Lewis structure because both iodine and oxygen atoms have charges. Therefore, reduce the charges (as below) by converting lone pairs to bonds.

Convert a lone pair of the oxygen atom to make a new I — O bond with the iodine atom as follows:

IOF5 Lewis Structure (Step 4)
Lone pair of oxygen is converted, and got the stable Lewis structure of IOF5 | Image: Learnool

Final structure

The final structure of IOF5 comprises a central iodine atom linked to five fluorine atoms and one oxygen atom. In this arrangement, the iodine atom utilizes an expanded valence shell to form six total bonds—a double covalent bond with the oxygen atom and five single covalent bonds with the fluorine atoms—leaving no lone pairs on the iodine. Within this layout, the oxygen atom fulfills its octet by maintaining two lone pairs, while each fluorine atom reaches a stable octet by retaining three lone pairs. This configuration represents the most stable state for the molecule because it results in a formal charge of zero for every atom involved. Accordingly, this specific electronic distribution serves as the definitive and most accurate Lewis representation of IOF5.

Next: CF3 Lewis structure

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Deep

Learnool.com was founded by Deep Rana, who is a mechanical engineer by profession and a blogger by passion. He has a good conceptual knowledge on different educational topics and he provides the same on this website. He loves to learn something new everyday and believes that the best utilization of free time is developing a new skill.

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