IO2- Lewis structure

IO₂^– (iodite) has one iodine atom and two oxygen atoms.

In IO₂^– Lewis structure, there is one single bond and one double bond around the iodine atom, with two oxygen atoms attached to it. The oxygen atom with a single bond has three lone pairs, the oxygen atom with a double bond has two lone pairs, and the iodine atom also has two lone pairs.

Also, there is a negative (-1) charge on the oxygen atom with a single bond.

Alternative method: Lewis structure of IO₂^–

Rough sketch

• First, determine the total number of valence electrons

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

Hence, iodine has seven valence electrons and oxygen has six valence electrons.

Since IO₂^– has one iodine atom and two oxygen atoms, so…

Valence electrons of one iodine atom = 7 × 1 = 7
Valence electrons of two oxygen atoms = 6 × 2 = 12

Now the IO₂^– has a negative (-1) charge, so we have to add one more electron.

So the total valence electrons = 7 + 12 + 1 = 20

Learn how to find: Oxygen valence electrons

• Second, find the total electron pairs

We have a total of 20 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 = 20 ÷ 2 = 10

• Third, determine the central atom

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

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

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

• And finally, draw the rough sketch

Lone pair

Here, we have a total of 10 electron pairs. And two I — O bonds are already marked. So we have to only mark the remaining eight 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 oxygen is a period 2 element, so it can not keep more than 8 electrons in its last shell.

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

So for each oxygen, there are three lone pairs, and for iodine, there are two lone pairs.

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 – 4 – ½ (4) = +1

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

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

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:

Final structure

The final structure of IO₂^– features a central iodine atom connected to two oxygen atoms. In this configuration, the iodine atom utilizes an expanded valence shell to form one double bond and one single bond with the surrounding oxygens. Within this layout, the iodine atom and the double-bonded oxygen atom carry a formal charge of zero, while the single-bonded oxygen atom holds a -1 formal charge. The iodine atom completes its electronic arrangement with two lone pairs, the double-bonded oxygen maintains two lone pairs, and the negatively charged oxygen retains three lone pairs. Accordingly, this specific electronic distribution serves as the definitive and most accurate Lewis representation of the iodite ion.

To properly represent this as a polyatomic ion, the entire Lewis structure is enclosed within square brackets. The overall charge of 1- is then written as a superscript outside the brackets at the top right, indicating that the structure possesses one additional electron beyond the valence count of the neutral atoms.

Next: C₃H₈O Lewis structure

External video

• How to Draw the Lewis Dot Structure for IO2 – (Iodite ion) – YouTube • Wayne Breslyn

External links

• https://lambdageeks.com/io2-lewis-structure/
• https://www.chegg.com/homework-help/questions-and-answers/draw-lewis-structure-io2-middle-puts-negative-one-formal-charge-one-o-zero-formal-charge-o-q25758640
• https://study.com/academy/answer/draw-the-lewis-structure-for-io2-give-the-number-of-electrons-in-each-species.html
• https://www.numerade.com/ask/question/in-the-lewis-dot-structure-of-the-iodite-ion-i02-what-is-the-formal-charge-on-the-iodine-atom-lq-j-9-a-2-b-1-c-0-d-1-e-2-76782/
• https://www.answers.com/Q/What_is_the_Lewis_structure_of_IO2-