Carbon dioxide is a colourless, odourless, incombustible gas produced by the combustion of carbon. The carbon-oxygen ratio in a CO2 molecule is 1:2. Two double bonds connect the carbon and oxygen atoms in the Lewis structure. Two oxygen atoms are present at the terminals, where they share electrons and form bonds with the central carbon atom.
Lewis structure diagrams show how many valence electrons are available within an atom for bond formation. It also allows for the visualisation of the behaviour of the valence electrons within the molecule as well as the determination of whether or not a lone pair of electrons exist.
Table of Contents
- How to draw Lewis Structure for CO2
- Molecular Geometry of CO2
- Hybridization of CO2
- Polarity of CO2
- Frequently Asked Questions – FAQs
How to Draw Lewis Structure of CO2
There are a few steps that need to be followed to attain the stable and correct Lewis structure which are as follows-
1. Determine the total number of electrons in the carbon and oxygen valence shells.
In the periodic table,
Oxygen belongs to the VIA group and has six electrons in its final shell.
Carbon is a member of the IVA group and has four electrons in its valence shell.
Therefore, the total number of valence electrons required to draw the Lewis structure of CO2 = 6(2) + 4 = 16
2. Total electron pairs exist in the form of lone pairs and bonds.
Total electron pairs are calculated by dividing the total valence electron count by two. For CO2, the total number of electron pairs is eight.
3. Determine the central atom.
Carbon will be the central atom because its valence (4) is greater than that of oxygen (2).
4. Mark atoms with lone pairs.
- The molecule contains two C-O bonds. As a result, only six electron pairs remain to be marked on atoms.
- Normally, those remaining electron pairs should be started to mark on outside atoms, but the oxygen atom can only hold eight electrons in its last shell. As a result, we can label electron pairs on oxygen atoms.
- Each oxygen will be able to keep three lone pairs. All of the remaining six electron pairs are now marked.
- As a result, there are no more lone pairs to mark in the carbon atom.
5. If there are charges on atoms, mark them.
As shown in the diagram below, each oxygen and carbon atom has a charge.
6. To obtain the best Lewis structure, minimise charges on atoms by converting lone pairs to bonds.
When every atom in a molecule has a charge, the structure is unstable. As a result, atom charges must be reduced. As the first step in reducing charges, we can convert a lone pair of oxygen atoms to form a bond with a carbon atom.
We can form a bond with a carbon atom by converting a lone pair of other oxygen atoms furthermore. Atoms will then have no charges.
In addition, there are two double bonds surrounding carbon atoms in the CO2 Lewis structure.
7. Check the stability of the structure
It can be checked by using the formula-
Formal charge = Valence Electrons – Unbonded Electrons – ½ Bonded Electrons
| Elements | Oxygen | Carbon |
|---|---|---|
| Formula Applied | Valence electrons = 6
Lone pair electrons = 4 Shared pair electrons (1 double bond) = 4 |
Valence electrons = 4
Lone pair electrons = 0 Shared pair electrons (2 single bond) = 8 |
| Formal Charge | (6 – 4 – 4/2) = 0 | (4 – 0 – 8/2) = 0 |
Since the overall formal charge is zero, the above Lewis structure of CO2 is most appropriate, reliable, and stable in nature.
Molecular Geometry of CO2
CO2 molecular geometry is based on a linear arrangement. The presence of a sigma bond and valence electron pairs repelling each other force them to move to the opposite side of the carbon atom, resulting in this geometric shape. As a result, the carbon atom takes on a linear molecular shape with symmetric charge distribution.
The bond angle of carbon dioxide is 180°.
Hybridization in CO2
CO2 hybridization is sp hybridization, with each carbon atom forming two sp hybrid orbitals. One of the two-hybrid orbitals will form a bond with one oxygen atom, while the other will form a bond with another oxygen atom. The remaining two p electrons will be used to form a pi (𝜋) bond.
Polarity of CO2
CO2 is nonpolar because it has a linear, symmetrical structure, and no unequal valence electron sharing takes place. The two oxygen atoms have equal electronegativity, so they pull electron density from carbon at an angle of 180 degrees from either direction.
Frequently Asked Questions on Lewis Structure of Carbon Dioxide
Explain the Lewis structure of CO2.
Carbon is the central atom in the Lewis structure of CO2 because it is the least electronegative element in the molecule. Two oxygen atoms are found at the terminals, where they share electrons and form a double bond with the carbon atom.
How many lone pairs are there in the Lewis structure CO2?
Each oxygen atom in the CO2 molecule has two lone pairs of electrons. There are no lone pairs in the carbon atom. Double bonds exist between carbon and oxygen.
Is CO2 polar or non-polar?
CO2 is nonpolar because it has a linear, symmetrical structure, and no unequal valence electron sharing takes place.
What is the shape of the CO2 molecule?
The shape of the CO2 molecule is linear. The presence of a sigma bond and repelling valence electron pairs forces oxygen atoms to move to the opposite side of the carbon atom, resulting in this geometric shape.
How many resonance structures are there for CO2?
There are three resonance structures for CO2.
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