CO2 Lewis Structure in 6 Steps (With Images)

So you have seen the above image by now, right?

Let me explain the above image in short.

CO2 lewis structure has a Carbon atom (C) at the center which is surrounded by two Oxygen atoms (O). There are 2 double bonds between the Carbon atom (C) and each Oxygen atom (O). There are 2 lone pairs on both the Oxygen atoms (O).

If you haven’t understood anything from the above image of CO2 (carbon dioxide) lewis structure, then just stick with me and you will get the detailed step by step explanation on drawing a lewis structure of CO2.

So let’s move to the steps of drawing the lewis structure of CO2.

Steps of drawing CO2 lewis structure

Step 1: Find the total valence electrons in CO2 molecule

In order to find the total valence electrons in CO2 (carbon dioxide) molecule, first of all you should know the valence electrons present in carbon atom as well as oxygen atom.
(Valence electrons are the electrons that are present in the outermost orbit of any atom.)

Here, I’ll tell you how you can easily find the valence electrons of carbon as well as oxygen using a periodic table.

Total valence electrons in CO2 molecule

→ Valence electrons given by carbon atom:

Carbon is group 14 element on the periodic table. ^[1] Hence the valence electrons present in carbon is 4.

You can see the 4 valence electrons present in the carbon atom as shown in the above image.

→ Valence electrons given by oxygen atom:

Oxygen is group 16 element on the periodic table. ^[2] Hence the valence electrons present in oxygen is 6.

You can see the 6 valence electrons present in the oxygen atom as shown in the above image.

Hence, 

Total valence electrons in CO2 molecule = valence electrons given by 1 carbon atom + valence electrons given by 2 oxygen atoms = 4 + 6(2) = 16.

Step 2: Select the central atom

For selecting the center atom, you have to remember that the atom which is less electronegative remains at the center.

Now here the given molecule is CO2 (carbon dioxide) and it contains carbon atom (C) and oxygen atoms (O).

You can see the electronegativity values of carbon atom (C) and oxygen atom (O) in the above periodic table.

If we compare the electronegativity values of carbon (C) and oxygen (O) then the carbon atom is less electronegative.

So here the carbon atom (C) is the center atom and the oxygen atoms (O) are the outside atoms.

Step 3: Connect each atoms by putting an electron pair between them

Now in the CO2 molecule, you have to put the electron pairs between the carbon atom (C) and oxygen atoms (O).

This indicates that the carbon (C) and oxygen (O) are chemically bonded with each other in a CO2 molecule.

Step 4: Make the outer atoms stable

Now in this step, you have to check the stability of the outer atoms.

Here in the sketch of CO2 molecule, you can see that the outer atoms are oxygen atoms.

These outer oxygen atoms are forming an octet and hence they are stable.

Also, in step 1 we have calculated the total number of valence electrons present in the CO2 molecule.

The CO2 molecule has a total 16 valence electrons and all these valence electrons are used in the above sketch of CO2.

Hence there are no remaining electron pairs to be kept on the central atom. 

So now let’s proceed to the next step.

Step 5: Check the octet on the central atom. If it does not have octet, then shift the lone pair to form a double bond or triple bond.

In this step, you have to check whether the central carbon atom (C) is stable or not.

In order to check the stability of the central carbon (C) atom, we have to check whether it is forming an octet or not.

Unfortunately, the carbon atom is not forming an octet here. Carbon has only 4 electrons and it is unstable.

Now to make this carbon atom stable, you have to shift the electron pair from the outer oxygen atom so that the carbon atom can have 8 electrons (i.e octet).

But after shifting one electron pair, the carbon atom is still not forming an octet as it has only 6 electrons. 

So again we have to shift one more electron pair from the other oxygen atom.

After shifting this electron pair, the central carbon atom will get 2 more electrons and thus its total electrons will become 8.

You can see from the above picture that the carbon atom is forming an octet.

And hence the carbon atom is stable.

Now let’s proceed to the final step to check whether the lewis structure of CO2 is stable or not.

Step 6: Check the stability of lewis structure

Now you have come to the final step in which you have to check the stability of lewis structure of CO2.

The stability of lewis structure can be checked by using a concept of formal charge.

In short, now you have to find the formal charge on carbon (C) atom as well as oxygen (O) atoms present in the CO2 molecule.

For calculating the formal charge, you have to use the following formula;

Formal charge = Valence electrons – (Bonding electrons)/2 – Nonbonding electrons

You can see the number of bonding electrons and nonbonding electrons for each atom of CO2 molecule in the image given below.

For Carbon (C) atom:
Valence electrons = 4 (because carbon is in group 14)
Bonding electrons = 8
Nonbonding electrons = 0

For Oxygen (O) atom:
Valence electrons = 6 (because oxygen is in group 16)
Bonding electrons = 4
Nonbonding electrons = 4

Formal charge	=	Valence electrons	–	(Bonding electrons)/2	–	Nonbonding electrons
C	=	4	–	8/2	–	0	=	0
O	=	6	–	4/2	–	4	=	0

From the above calculations of formal charge, you can see that the carbon (C) atom as well as oxygen (O) atom has a “zero” formal charge.

This indicates that the above lewis structure of CO2 is stable and there is no further change in the above structure of CO2.

In the above lewis dot structure of CO2, you can also represent each bonding electron pair (:) as a single bond (|). By doing so, you will get the following lewis structure of CO2.

I hope you have completely understood all the above steps.

For more practice and better understanding, you can try other lewis structures listed below.

Try (or at least See) these lewis structures for better understanding:

NO2 lewis structure	NH3 lewis structure
HCN lewis structure	H2O lewis structure
N2 lewis structure	O2 lewis structure