CO2 Lewis Structure, Characteristics: 13 Facts You Should Know


This article contains detailed facts about 13 important factors of CO2 including CO2 lewis structure, bond angle, shape, etc.

In the CO2 lewis structure, the shape of the molecule is linear. All the atoms of CO2 molecule lie in the same plane. The central atom c is sp hybridized here and there are two sigma bonds and two π bonds are present between C and O atoms. Due to its symmetrical structure molecule is nonpolar.

The C-O bond length is near about 116 pm. Due to the double bond character bond length gets decreased. The molecule itself is neutral but in the aqueous medium, it acts as an acid.

Some important facts about CO2

In the physical state CO2 is a colorless gaseous molecule. It is almost 50% denser than the normal air.

The molar mass of the CO2 molecule is 44.03 g/mol. As it is a gaseous molecule so it has vapor pressure and the value of vapor pressure is 5.72 MPa at 300 C temperature. The crystal structure of this molecule is trigonal but the geometry is linear. At -78.50 C temperature, it converts to its solid state and the temperature is so low and then it is called dry ice. In many organic reactions, there will be required of dry ice.

Full combustion of C in the open-air presence of Oxygen gives CO2. CO2 is also a byproduct of the industrial production of H by stem.

C + O2 = CO2

1.    How to draw CO2 lewis structure?

Lewis dot structure is a very important parameter for every covalent molecule. It helps to find out the geometry, bond angle, and several valence electrons of a molecule.

TO draw the CO2 lewis structure we have to follow a few steps.

First of all, we should count the total number of valence electrons of C and O atoms and then added together.

From the electronic configuration, C has four electrons in its valence shell and O has six electrons. The valence electrons count in the CO2 lewis structure will be 4+6+6 =16. According to the octet rule the electrons needed 3*8 =24 electrons and the shortage of electrons will be 24-16 = 8 electrons and the bond required 8/2 = 4 bonds. So, in the CO2 lewis structure, there will be a minimum of 4 bonds is required.

CO2 lewis structure
CO2 Lewis Structure

So, we connect C and two O atoms via single bonds, and then to complete the octet we add multiple bonds between C and O atoms. Ultimately there are two sigma bonds and two π bonds are present between C and O atoms.

Based on charge and less electronegativity C will be the central atom and O are the terminal atoms.

Now we assigned lone pair over the respective atoms. C has no extra electron I n its valence shell after multiple bond formation. So, it has no lone pairs. But O has four electrons extra after bond formation and they exist as two pairs of lone pairs over O atoms. The molecule is neutral so no need to add a positive or negative charge over it.

2.    CO2 lewis structure shape

CO2 lewis structure shape can be predicted from the VSEPR (Valence Shell Electrons Pair Repulsion) theory. According to this theory if a molecule has common formula AX2 type then it is generally adopted linear structure if a central atom has no lone pairs.

CO2 Lewis Shape

In the CO2 lewis structure, for the single bond, the electrons counts are 2+2=4 electrons. So, according to the VSEPR theory if the electrons count for a covalent molecule will be 4 then it adopts a linear structure. Also, CO2 is an AX2-type molecule and central C has no lone pairs.

To complete the octet there will be added two multiple bonds. C is the central atom and two O are resides on two sides of C at the terminal position.

3.    CO2 valence electrons

In the CO2 lewis structure, C and O have several electrons in their outermost orbital which can participate in bond formation, and by this electron, they can complete their octet. These electrons are known as Valence electrons.

CO2 Valence Electrons

To calculate the valence electrons in the CO2 lewis structure, we have to see the electronic configuration of C and O. C is the IVA element and O is the VIA element in the periodic table. The electronic configuration of C and O are [He]2s22p2 and [He]2s22p4. So, C has four electrons and O has six electrons in their respective valence shell. These electrons are their valence electrons because these electrons will participate in the bond formation.

So, the total number of valence electrons in the CO2 lewis structure is 4+(6*2)= 16 electrons.

4.      CO2 lewis structure lone pairs

After the valence electrons count for the CO2 lewis structure it is necessary to calculate the lone pairs of the molecule. Lone pairs are also present in the valence shell but not involved in the bond formation.

CO2 Lone Pairs

C is group 2nd period 14th element so it has four electrons in its outermost shell and all the electrons are involved in the sigma as well as π bonding with two O atoms. So, it has no extra electrons in its valence shell so C is lack of lone pairs.

But O is group 2nd period 16th element and it has six electrons in its valence 2s orbital and among six electrons two are involved in the double bond formation with the C atom. So, it has four electrons in its valence shell which are not participating in the bond formation and those four electrons exist as two pairs of lone pairs over each O atom.

 So, the total number of lone pairs over the CO2 lewis structure for two O atoms is 2*2 = 4 pairs of lone pairs.

5.    CO2 lewis structure octet rule

C, as well as O, try to complete their valence orbital by accepting four and two electrons respectively. After accepting electrons their electronic configuration will be as same as the nearest noble gas configuration. This is called the octet rule.

CO2 Octet

C needs four electrons in its valence shell so, it shares four electrons with two O atoms by forming two sigma bonds and two π bonds to complete its octet.

Again, for O it is the group 16th element and has six electrons in its valence shell and required two more to complete its octet. So, it formed one sigma and one π bond with c to share electrons and complete its octet too.

6.    CO2 lewis structure formal charge

The formal charge of CO2 is evident whether the molecule is charged or not. Calculating the formal charge of CO2 lewis structure by assuming the same electronegativity of every atom in the molecule like C and O.

The formal charge is a hypothetical concept and it has a particular formula to determine.

The formula we can use to calculate the formal charge, F.C. = Nv – Nl.p. -1/2 Nb.p.

Where Nv is the number of electrons in the valence shell or outermost orbital, Nl.p is the number of electrons in the lone pair, and Nb.p  is the total number of electrons that are involved in the bond formation only.

In the CO2 lewis structure, C and O are different substituents, so we have to calculate the formal charge of C and o atoms individually by using the above formula.

The formal charge over C is, 4-0-(8/2) = 0

The number of valence electrons for C is 4, there are no lone pairs over C and C formed four bonds so in the four bonds there are eight electrons involved.

The formal charge over O is, 6-4-(4/2) = 0

O has six electrons in its valence shell and four electrons are in two pairs of lone pairs. O forms two bonds with C and each bond contains two electrons so there are four electrons are involved in two bonds.

So, from the above calculation, we can say that there is no formal charge present individual atoms sop the CO2 lewis structure is neutral.

7.    CO2 lewis structure bond angle

In the CO2 lewis structure, the O-C-O bond angle is 1800 which is for linear geometry. Bond angle is an important parameter for every covalent molecule to arrange the individual atoms properly in space.

CO2 Bond Angle

From the VSEPR theory, if a molecule is an AX2 type and the central atom has no lone pairs then the bond angle of the molecule is 1800 which reflects its structure linearity. CO2 lewis structure is AX2 type and the molecule adopts linear structure so the O-C-O bond angle is expected to be 1800.

Two O atoms carry lone pairs which are very far from each other so there is no chance for lone pair repulsion. The molecule is very much rigid due to double bonds so it could not change its bond angle as well as its structure.

8.    CO2 lewis structure resonance

In the CO2 lewis structure, there will be different skeleton forms in resonance. Resonance is the hypothetical concept by which the delocalization of electron clouds occurs between O and C in different skeleton forms.

CO2 Resonating Structure

There are four independent resonating structures in the CO2 lewis structure. Structure III is the most contributing structure as it contains more covalent bonds than structure IV. But in structure IV electronegative atom O gets a positive charge and electropositive atom C gets a negative charge which is a destabilization factor. So, structure III is the most contributing structure to the resonance of CO2.

Structure II is more contributing than structure I. In structure I, two positive charges are present on the same atom and there is a lower number of covalent bonds.

9.    CO2 hybridization

In the CO2 lewis structure, the central atom C undergoes sp hybridization with two O atoms. Hybridization is a theoretical concept by which two or more orbitals having different energy and orientation under mix produce a new hybrid orbital of an equivalent energy to form a stable covalent bond.

There is a specific formula to calculate the hybridization of any covalent molecule.

H = 0.5(V+M-C+A), where H= hybridization value, V is the number of valence electrons in the central atom, M = monovalent atoms surrounded, C=no. of cation, A=no. of the anion.

By this formula, we can calculate how many orbitals are involved in the hybridization. To calculate the hybridization, we cannot consider the π or multiple bonds.

In the CO2 lewis structure, there are two electrons of c are involved in two sigma bonds with two O atoms. So, the hybridization orbital of C in the CO2 lewis structure is, ½(2+2+0+0) = 2 (sp)

StructureHybridization value      State of hybridization of central atom  Bond angle
Linear 2sp /sd / pd   1800
Planner trigonal  3sp1200
Tetrahedral   4sd3/ sp3 109.50
Trigonal bipyramidal 5sp3d/dsp 900 (axial), 1200(equatorial)
Octahedral 6sp3d2/ d2sp3     900
Pentagonal bipyramidal  7sp3d3/d3sp3        900,720

                 From the above table we can say that if the two orbitals are involved in the hybridization then the molecule will be sp hybridized.

CO2 Hybridization

From the box diagram of the CO2 lewis structure, we can say that in-ground state there are two electrons in the s orbital and two electrons in the p orbitals of C. When the system gets energized then one electron from the s orbital gets promoted to the vacant p orbital and now C has four unpaired electrons in its valence shell and it can ready for bond formation.

Now in this hybridization one O forms a sigma bond with s orbital and one O forms a sigma bond with an electron in p orbitals of C and the remaining two unpaired electrons in p orbitals of C form π bonds with two O. we cannot consider the π bonds.

So, one s orbital and one p orbital is involved in this hybridization of CO2. So, the hybridization will be sp.

From the hybridization table, we can also say that the linear molecule will be sp hybridized and the bond angle is 1800.

10.    CO2 solubility

The solubility of CO2 in different solvents depends upon the nature and temperature as well. CO2 is a nonpolar molecule so it is expected to be soluble in the nonpolar solvent (like dissolves like).

But Co2 can be soluble in polar solvents like water it is a gaseous molecule so it gets soluble by the process of adsorption. At standard room temperature, 1.44 g of CO2 can be soluble in 1L water. So, the solubility of CO2 in water is very poor.

11.    Is CO2 ionic?

CO2 possesses some % of ionic character. According to Fajan’s rule, all the covalent molecules have some % ionic character based on their ionic potential and polarizability.

The size of C is very small so it has enough ionic potential to polarize the O atoms. Due to the polarizable of O atoms, it shows some ionic character and it can break little in ions.

12.    Is Co2 acidic or basic?

The CO2 molecule is neither acidic nor basic in itself. But in an aqueous medium, it acts as an acid.

In the CO2 lewis structure, there is no ionizable proton present or hydroxide group. So, it is neutral in a normal state. But when it is soluble in water it forms organic mild acid Carbonic acid, (H2CO3). Due to the formation of the acid whole, the solution becomes acidic as water is neutral.  So, in the aqueous medium, it acts as an acid.

CO2 + H2O = H2CO3

13.    Is CO2 polar or nonpolar?

The CO2 molecule is nonpolar in its symmetric shape. There is no dipole moment in this molecule.

A molecule is polar or nonpolar it depends upon the resultant value of the dipole moment of this molecule. In the CO2 lewis structure, the molecule is linear and symmetric structure so the direction of two dipole moments is exactly opposite and cancels out each other.

CO2 Dipole Moment

So, the net resultant dipole-moment for the CO2 molecule is zero and makes the molecule nonpolar.

14.    Is CO2 symmetrical or asymmetrical?

The shape of the CO2 molecule is symmetrical due to its linear structure. C atom lies central position and two O are two opposite site of C and makes a linear geometry with a symmetrical shape.

But in the CO2 molecule, there is seen a stretching property where one C-O bond gets increases and the other remains the same then the molecule no longer lies in the symmetric form, and only then does it have some dipole moment.

CO2 Asymmetric Stretching

Conclusion

From the above-detailed discussion about the CO2 lewis structure, we can conclude that CO2 is linear and a symmetric molecule having a bond angle of 1800 and for this symmetrical structure it is non-polar. The molecule itself is neutral but the aqueous solution will be acidic.

Biswarup Chandra Dey

Chemistry is not all about reading line by line and memorize, it is a concept to understand in easy way and here I am share with you the concept about chemistry which I learn because knowledge is worth to share it.

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