Carbon Dioxide is an acidic colorless and odorless gas with a chemical formula CO2. It is majorly used in the food industry, chemical industry, winemaking, fire extinguisher, agriculture, oil industry, etc.
It is present as a minor component in the earth’s atmosphere, obtained from both natural and human sources like decomposition, respiration, combustion of carbon-containing compounds, deforestation, and more.
However, due to human activities, its atmospheric concentration has been rising extensively, upsetting the natural balance and leading to Global warming.
In this article, we will provide valuable information regarding carbon dioxide such as its structure, intermolecular forces, polarity, etc.
So, what intermolecular forces are present in CO2? Carbon dioxide is a linear and non-polar molecule so the only intermolecular force present in CO2 is London dispersion forces or Van der Walls forces.
What are Intermolecular Forces?
Intermolecular forces are defined as the attractive or repulsive forces present between atoms, molecules, or ions of the substance when they are placed close to each other.
These forces mediate the interaction between atoms or molecules of the substance and thus become responsible for most of their physical and chemical characteristics.
The intermolecular forces arise because of the following interactions:
Polar molecules like HCl, NH3 have dipole-dipole interaction as forces of attraction. These have permanent dipoles because of existing differences in the electronegativity of atoms.
In dipole-dipole interaction, electrons assemble at one end of the molecule having higher electronegativity.
Thus, one end of the molecule acquires a partial negative charge and the other end acquires a partial positive charge and thus becomes a polar molecule.
For example, in an HCl molecule, the Chlorine atom is more electronegative than Hydrogen so, electrons congregate near the chlorine atom and it becomes partially negative.
Whereas, the hydrogen becomes partially positive. In this way, a dipole with separated electrical polarity is formed and when two molecules of HCl come closer, the positive end (H-end) of one molecule attracts the negative end (Cl-end) of another molecule and forms a bond.
This type of interaction occurs between an ion and a polar molecule. Dissolution of ionic substances in polar solvents occurs due to ion-dipole interaction. The strength of this interaction depends on certain factors like
• Charge and size of the ion
• Magnitude of dipole moment and size of a polar molecule
For example, when an ionic substance like NaCl dissolves in a polar solvent like H20, the former breaks down into its constituent ions, Na+ and Cl-.
Similarly, a water molecule forms a dipole where the hydrogen end becomes partially positive and the oxygen end becomes partial negative.
Thus, the positively charged sodium ions attract the negative end (O-end) of the water molecule and negatively charged Chloride ions attract the positive end (H-end) of the water molecule and form a bond.
Ion-Induced Dipole Interactions:
This interaction occurs between an ion and a non-polar molecule. In this case, the charge on the ion deforms the electron cloud of a non-polar molecule and induces polarity in it to form a weak bond.
The strength of this interaction depends on –
• Charge of ion
• Ease of polarisability of the non-polar molecule
Dipole-Induced Dipole Interaction:
This type of interaction occurs between a polar molecule with a permanent dipole and a non-polar molecule.
Similar to ion-induced dipole interactions, polar molecule deforms the electron cloud of an electrically neutral molecule and induces polarity in it, the strength of this interaction depends on –
• Dipole moment of a polar molecule
• Ease of polarisability of the electrically neutral molecule
London forces or Dispersion forces:
London forces are the weakest intermolecular forces. This type of interaction occurs between two electrically symmetrical non-polar molecules due to the development of instantaneous dipole.
It is believed that instantaneous dipole may develop in a non-polar molecule because of momentarily distortion of its electron cloud.
As a result, one part of the molecule becomes slightly positive and the other becomes slightly negative for a very short span of time.
This instantaneous dipole further distorts the electron density of neighboring non-polar molecule and induce a dipole in them.
This type of interaction occurs only at a short distance and its strength depends on the polarisability of molecules.
This type of electrostatic attraction occurs between hydrogen and highly electronegative atom like oxygen, nitrogen, or fluorine.
This is a special case of dipole-dipole interaction in which covalently bonded H-O, H-N, or H-F form a very strong dipole.
The strength of the Hydrogen bond depends on the coulombic interaction between the hydrogen atom of one molecule and the lone-pair electrons of the electronegative atom like F, O, or N of other molecules.
What are the Intermolecular Forces Present in CO2?
The following chart helps in determining the intermolecular force for any molecule.
Let’s determine the intermolecular force present in CO2
Are ions present?
As CO2 is a non-ionic species lacking any positive or negative charge on it, no ions are present.
Are polar molecules present?
While drawing the Lewis structure of CO2, when Carbon is placed at the center with two single C-O bonds, carbon does not have an octet.
So, lone pairs from each surrounding oxygen atom are used to form a double bond with carbon.
In this way, carbon has two electron domains with no lone pair and according to VSEPR theory, CO2 has linear geometry with a bond angle of 180o.
Being more electronegative than Carbon, both oxygen atoms pull electron clouds toward themselves, and two poles of the same magnitude will be created in opposite directions and nullify each other effect. So, no polar molecules are present.
Hence, only London forces or Dispersion forces are present as intermolecular forces in CO2.
Despite being non-polar, momentarily distortion in electronic charge distribution develops instantaneous dipole on CO2 molecule for a very short time, which further distorts the electron density of the other CO2 molecule.
These two temporary dipoles form a weak bond between them.
Intermolecular Forces vs Intramolecular Forces:
|Intermolecular Forces||Intramolecular Forces|
|These forces occur between molecules themselves||These forces occur between atoms within a molecule|
|Weaker forces||Stronger forces|
|Determine the state of matter and its physical properties||Determine chemical behavior of a substance|
|Are attractive in nature||Form chemical bonds|
|Types of intermolecular forces include –
London or Dispersion forces
|Types of Intramolecular forces include
Ionic bonding: In this type of bonding, the complete transfer of electrons occurs between atoms having differences in electronegativities.
Covalent bonding: In this type of bonding, sharing of electrons occurs between two non-metal atoms having similar electronegativity.
Metallic bonding: In this type of bonding, a strong force occurs between delocalized valence electrons and positively charged metal nuclei within the metal structure.
Relative Strength of Intermolecular Forces
|Intermolecular Forces||Occurs between||Relative Strength|
|Ion-Dipole interaction||Ion and polar molecule||1. (Strongest)|
|Hydrogen bonding||Hydrogen atom and Oxygen/Fluorine/Nitrogen||2.|
|Dipole-dipole interaction||Partially oppositely charged ions||3.|
|London or Dispersion forces||Instantaneously induced dipoles||4. (Weakest)|
Is CO2 Polar or Non-polar?
The polarity of CO2 depends on –
• Presence of polar bonds
• Molecular orientation
In CO2, two double bonds are present between Carbon and Oxygen.
Oxygen is a more electronegative atom than carbon so, the former pulls the electron density towards itself and two polar bonds are formed between two.
The molecular geometry of CO2 is linear with a bond angle of 180 degrees. It means that one carbon atom is a central atom and two oxygen atoms on either side of the Carbon atom lie in a straight line.
So, the two polar bonds of equal magnitude are present on either side of the carbon atom, which cancels each other out and makes the CO2 molecule non-polar.
Which has Stronger Intermolecular Forces:
SO2 vs CO2
Intermolecular force present between SO2 molecules:
Being more electronegative than Sulphur, Oxygen pulls the electron cloud towards itself and two polar bonds are formed.
Moreover, it has V-shaped or bent molecular geometry with a bond angle of 119o so, bond polarities do not cancel each other out and SO2 becomes a polar molecule.
Hence, the intermolecular force present between SO2 molecules along with London forces is dipole-dipole interactions.
Intermolecular force present between CO2 molecules:
CO2 is a linear molecule so bond polarities cancel out each other. Hence, it becomes non-polar and the only intermolecular force present between CO2 molecules is London forces.
As discussed above, the strength of Dipole-dipole interaction is more than London forces so, SO2 molecules have stronger intermolecular force than CO2 molecules.
CH4 vs CO2
Intermolecular force present between CH4 molecules:
The electronegativity difference between Carbon and hydrogen is not enough to make a polar bond and the molecular geometry of CH4 is symmetrical tetrahedral.
Hence, the only intermolecular force present between CH4 molecules is London forces. Read out the article on CH4 Intermolecular Forces.
Intermolecular force present between CO2 molecules:
CO2 is a linear and non-polar molecule so, London forces exist between C02 molecules.
In this case, both molecules have similar intermolecular forces. However, the strength of London forces depends on the size of the molecule and CO2 has a bigger molecular size than CH4. Hence, CO2 has a stronger intermolecular force than CH4.
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CO2 is a non-toxic and non-combustible acidic gas. It is a one-carbon compound that forms two double bonds with surrounding oxygen atoms.
It has two polar bonds because of the electronegativity difference between carbon and oxygen. However, it has linear geometry with a bond angle of 180o. So, both bond polarities cancel each other and CO2 becomes a non-polar molecule.
The only intermolecular force present between non-polar molecules is London forces. Hence, CO2 molecules have London forces as the interactive force between them.
London forces are also known as induced dipole-induced dipole interaction because a momentary distortion in the electron cloud of one non-polar molecule develops dipole in it for a short time. And, this instantaneous dipole induces a dipole in the surrounding non-polar molecule.