O2 Lewis structure

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O₂ (oxygen) has two oxygen atoms.

In the O₂ Lewis structure, there is a double bond between the two oxygen atoms, and on each oxygen atom, there are two lone pairs.

Steps

Use these steps to correctly draw the O₂ Lewis structure:

#1 First draw a rough sketch
#2 Mark lone pairs on the atoms
#3 Calculate and mark formal charges on the atoms, if required
#4 Convert lone pairs of the atoms, and minimize formal charges
#5 Repeat step 4 if needed, until all charges are minimized, to get a stable Lewis structure

Let’s discuss each step in more detail.

#1 First draw a rough sketch

• First, determine the total number of valence electrons

In the periodic table, oxygen lies in group 16. Hence, oxygen has six valence electrons.

Since O₂ has two oxygen atoms, so…

Valence electrons of two oxygen atoms = 6 × 2 = 12

So the total valence electrons = 12

Learn how to find: Oxygen valence electrons

• Second, find the total electron pairs

We have a total of 12 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 = 12 ÷ 2 = 6

• Third, determine the central atom

Here, there are only two atoms and both atoms are oxygen, so we can assume any one as the central atom.

Let’s assume that the central atom is right oxygen.

• And finally, draw the rough sketch

#2 Mark lone pairs on the atoms

Here, we have a total of 6 electron pairs. And one O — O bond is already marked. So we have to only mark the remaining five electron pairs as lone pairs on the sketch.

Also remember that 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 atom is left oxygen.

So for left oxygen, there are three lone pairs, and for right oxygen, there are two lone pairs.

Mark the lone pairs on the sketch as follows:

#3 Calculate and mark formal charges on the atoms, if required

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

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

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

For right oxygen atom, formal charge = 6 – 4 – ½ (2) = +1

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

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

#4 Convert lone pairs of the atoms, and minimize formal charges

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

In the above structure, you can see that the central atom (right oxygen) forms an octet. And the outside atom (left oxygen) also forms an octet. Hence, the octet rule is satisfied.

Also, the above structure is more stable than the previous structures. Therefore, this structure is the stable Lewis structure of O₂.

Next: CO Lewis structure

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External video

• O2 Lewis Structure: How to Draw the Lewis Structure for Oxygen Gas (Diatomic Oxygen) – Wayne Breslyn

External links

• https://www.chemistryscl.com/general/O2-lewis-structure/
• https://techiescientist.com/o2-lewis-structure/
• https://whatsinsight.org/o2-lewis-structure-molecular-geometry/
• https://www.thegeoexchange.org/chemistry/bonding/Lewis-Structures/O2-Lewis-Structure.html
• https://www.makethebrainhappy.com/2019/12/the-lewis-dot-structure-for-o2.html
• https://sciencetrends.com/o2-oxygen-lewis-dot-structure/
• https://lambdageeks.com/o2-lewis-structure/