CO2 Molecular Geometry - Science Education and Tutorials

Carbon dioxide(CO2) has the composition of one carbon and two oxygen atoms. What is the molecular geometry of carbon dioxide?. Drawing and predicting the CO2 molecular geometry is very easy by following the given method. Here in this post, we described step by step to construct CO2 molecular geometry. Oxygen and carbon come from the 16th and 14th family groups in the periodic table. Oxygen and carbon have six and four valence electrons respectively.

Table of Contents

Key Points To Consider When drawing The CO2 Molecular Geometry

A three-step approach for drawing the CO2 molecular can be used. The first step is to sketch the molecular geometry of the CO2 molecule, to calculate the lone pairs of the electrons in the central carbon and terminal oxygen atoms; the second step is to calculate the CO2 hybridization, and the third step is to give perfect notation for the CO2 molecular geometry.

The CO2 molecular geometry is a diagram that illustrates the number of valence electrons and bond electron pairs in the CO2 molecule in a specific geometric manner. The geometry of the CO2 molecule can then be predicted using the Valence Shell Electron Pair Repulsion Theory (VSEPR Theory) and molecular hybridization theory, which states that molecules will choose the CO2 geometrical shape in which the electrons have from one another in the specific molecular structure.

Finally, you must add their bond polarities characteristics to compute the strength of the two C-O double bonds (dipole moment properties of the CO2 molecular geometry). Two oxygen-carbon double bonds in the carbon dioxide(CO2), for example, are polarised toward the slightly high electronegative value oxygen atoms, and because all two C-O double bonds have the same size and polarity, their sum is zero due to the CO2 molecule’s bond dipole moment due to pulling the electron cloud to the two side of linear geometry, and the CO2 molecule is classified as a nonpolar molecule.

The molecule of carbon dioxide(with linear shape CO2 molecular geometry) is tilted at 180 degree bond angle of O-C-O. It has a difference in electronegativity values between oxygen and carbon atoms, with oxygen’s pull the electron cloud being higher than carbon’s. But bond polarity of C-O is canceled to each other in the linear geometry. As a result, it has a zero permanent dipole moment in its molecular structure. The CO2 molecule has a nonzero dipole moment due to an equal charge distribution of negative and positive charges in the linear geometry.

Overview: CO2 electron and molecular geometry

According to the VSEPR theory, the CO2 molecule possesses linear molecular geometry. Because the center atom, carbon, has two C-O double bonds with the two oxygen atoms surrounding it. The O-C-O bond angle is 180 degrees in the linear CO2 molecular geometry. The CO2 molecule has a linear geometry shape because it contains two oxygen atoms in the linear form and two corners with no lone pairs of electrons on central carbon atom.

There are two C-O double bonds at the CO2 molecular geometry. After linking the two oxygen atoms and no lone pairs of electrons on the carbon atom in the linear form, it maintains the linear-shaped structure. In the CO2 molecular geometry, the C-O double bonds have stayed in the two terminals and no lone pairs of electrons on the carbon atom of the linear molecule.

The central carbon atom of CO2 has no lone pairs of electrons, resulting in linear CO2 electron geometry. However, the molecular geometry of CO2 looks linear-shaped and has no lone pairs of electrons on the carbon of the CO2 geometry. It’s the CO2 molecule’s slight symmetrical geometry. As a result, the CO2 molecule is nonpolar.

How to find CO2 hybridization and molecular geometry

Calculating lone pairs of electrons on carbon in the CO2 geometry:

1.Determine the number of lone pairs of electrons in the core carbon atom of the CO2 Lewis structure. Because the lone pairs of electrons on the carbon atom are mostly responsible for the CO2 molecule geometry planar, we need to calculate out how many there are on the central carbon atom of the CO2 Lewis structure.

Use the formula below to find the lone pair on the carbon atom of the CO2 molecule.
L.P(C) = V.E(C) – N.A(C-O)/2

Lone pair on the central carbon atom in CO2 = L.P(C)
The core central carbon atom’s valence electron in CO2= V.E(C)
Number of C-O bonds = N.A (C-O)
calculation for carbon atom lone pair in CO2 molecule.

For instance of CO2, the central atom, carbon, has four electrons in its outermost valence shell, two C=S double bond connections. This gives a total of four connections.

As a result of this, L.P(C) = (4 –4)/2=0

The lone pair of electrons in the carbon atom of the CO2 molecule is zero.

Calculating lone pair of electrons on the terminal oxygen in the CO2 geometry:

Finding lone pair of electrons for the terminal oxygen atom is not similar to the central carbon atom. We use the following formula as given below

Use the formula below to find the lone pair on the oxygen atom of the CO2 molecule.
L.P(O) = V.E(O) – N.A(C-O)

Lone pair on the terminal oxygen atom in CO2 = L.P(O)
Terminal oxygen atom’s valence electron in CO2 = V.E(O)
Number of C-O bonds = N.A ( C-O)
calculation for oxygen atom lone pair in CO2 molecule.

For instance of CO2, their terminal atoms, oxygen, have six electrons in their outermost valence shell, one C-O double bond connection. This gives a total of two C-O double bond connections. But we are considering only one connection for the calculation.

As a result of this, L.P(O) = (6 –2)=4

The lone pair of electrons in the oxygen atom of the CO2 molecule is four. Two oxygen atoms are connected with the central carbon atom.

In the CO2 electron geometry structure, the lone pairs on the central carbon atom are zero, lone pairs of electrons in the oxygen atom have two pairs(4 electrons). Two oxygen atoms have two lone pairs of electrons.

It means there are two lone pairs of electrons in the core carbon atom. No lone pair of electrons on the central carbon atom is responsible for the linear nature of CO2 molecular geometry. But in the structure oxygen atoms are polarised sidewise in their linear geometry.

The two lone pairs of electrons on the terminal oxygen atoms are placed at two ends of the CO2 geometry. Because the carbon atom is a lower electronegative value as compared with other atoms in the CO2 molecule. Two oxygen atoms are polarized towards the sidewise in the CO2 structure.

But in reality, the CO2 has four lone pairs of electrons on the two oxygen ends in its structure. This makes the CO2 more symmetrical in the structure of the molecule. Because there is no electric repulsion between bond pairs and lone pairs.

CO2 is mainly used as an organic solvent in most of the particular types of organic synthetic reactions. It is a nonpolar solvent and has a very similar structure to a CO2 molecule. But CO2 is in the gaseous state at normal temperature and pressure. Liquid CO2 is used as a solvent in some extreme reactions. Dry ice is nothing but the solid form of CO2.

But in the central, carbon atom has no lone pairs of electrons and two C-O bond pairs stay oppose to each other around 180 degrees.

Calculate the number of molecular hybridizations of the CO2 molecule

What is CO2 hybridization? This is a very fundamental question in the field of molecular chemistry. All the molecules are made of atoms. In chemistry, atoms are the fundamental particles. There are four different types of orbitals in chemistry. They are named s, p, d, and f orbitals.

The entire periodic table arrangement is based on these orbital theories. Atoms in the periodic table are classified as follows:

s- block elements
p- block elements
d-block elements
f-block elements
Atoms are classified in the periodic table

CO2 molecule is made of one carbon, two oxygen atoms. The carbon and oxygen atoms have s and p orbitals. But carbon atom has s and p orbitals in the ground state. Carbon comes as the first element in the periodic table of carbon families. The oxygen atom also belongs to the oxygen family group. But it falls as the first element in the periodic table.

When these atoms combine to form the CO2 molecule, its atomic orbitals are mixed and form unique molecular orbitals due to hybridization.

How do you find the CO2 molecule’s hybridization? We must now determine the molecular hybridization number of CO2.

The formula of CO2 molecular hybridization is as follows:
No. Hyb of CO2= N.A(C-O bonds) + L.P(C)
No. Hy of CO2 = the number of hybridizations of CO2
Number of C-O bonds = N.A (C-O bonds)
Lone pair on the central carbon atom = L.P(C)
Calculation for hybridization number for CO2 molecule

In the CO2 molecule, carbon is a core central atom with two oxygen atoms connected to it. It has no lone pairs of electrons on carbon. The number of CO2 hybridizations (No. Hyb of CO2) can then be estimated using the formula below.

No. Hyb of CO2= 2+0=2

The CO2 molecule hybridization is two. The oxygen and carbon atoms have s and p orbitals. The sp hybridization of the CO2 molecule is formed when one s orbital and one p orbitals join together to form the CO2 molecular orbital.

Molecular Geometry Notation for CO2 Molecule :

Determine the form of CO2 molecular geometry using VSEPR theory. The AXN technique is commonly used when the VSEPR theory is used to calculate the shape of the CO2 molecule.

The AXN notation of CO2 molecule is as follows:
The central carbon atom in the CO2 molecule is denoted by the letter A.
The bound pairs (two C-O bonds) of electrons to the core carbon atom are represented by X.
The lone pairs of electrons on the central carbon atom are denoted by the letter N.
Notation for CO2 molecular geometry

We know that carbon is the core atom of CO2, with two electron pairs bound (two C-O) and no lone pairs of electrons. The general molecular geometry formula for CO2 is AX2.

According to the VSEPR theory, if the CO2 molecule has an AX2 generic formula, the molecular geometry and electron geometry will both be linear-shaped forms.

Name of Molecule	carbon dioxide
Chemical molecular formula	CO2
Molecular geometry of CO2	linear
Electron geometry of CO2	linear
Hybridization of CO2	sp
Bond angle (O-C-O)	180º degree
Total Valence electron for CO2	16
The formal charge of CO2 on carbon	0

Summary:

In this post, we discussed the method to construct CO2 molecular geometry, the method to find the lone pairs of electrons in the central carbon atom, CO2 hybridization, and CO2 molecular notation. Need to remember that, if you follow the above-said method, you can construct the CO2 molecular structure very easily.