Is O2 Polar or Nonpolar?

Oxygen is a chemical element with the symbol O and atomic number 8. It is a highly reactive non-metallic chemical in group 16 (the chalcogen group) of the periodic table. It is an oxidising agent that quickly forms oxides with several substances. There are numerous known allotropes of oxygen, the most stable of which is O2. It is also known as diatomic oxygen and molecular oxygen, and its presence in the atmosphere is significant.

Consequently, is O2 Polar or Non-Polar? The oxygen (O2) molecule is nonpolar due to its diatomic structure and equal electronegativity of both atoms. As a result, both atoms share equal charges and neither atom possesses partial charges. The result is that O2 is a nonpolar molecule with zero dipole moment.

Polarity’s foundation for every molecule

A polar bond is one in which the positive and negative charge centres do not coincide.

If two atoms are involved in the creation of a polar bond, one must be more electronegative than the other in order to be able to attract a partial negative charge.

Consequently, the less electronegative atom retains some positive charge, which contributes to the existence of a dipole moment.

Thus, Polar molecules possess:

A dipole moment above 0D

A higher electronegative differential than 0.4

Positive and negative charges accumulate at the molecule’s poles.

Exceptional melting and boiling points

Absence of Symmetry

Insoluble or sparingly soluble in non-polar solvents, yet soluble in polar solvents.

Refer to the article for the explanation of PCl3’s polarity.

Non-polar molecules are distinguished from polar molecules by the following property differences:

They have a net dipole moment of zero

Atomic electronegative difference ranges between 0 and 0.4 (negligible)

No charge accumulation at the poles.

Reduce melting and boiling temperatures

Symmetric molecular structure

Consult the page for the explanation of CS2’s non-polarity.

In order to draw a concrete conclusion on the polarity of any molecule or element, the aforementioned attributes might be compared.

Why is O2 a nonpolar molecule?

The O2 molecule is termed nonpolar due to the following characteristics. Let’s examine the following factors to determine the polarity of a molecule.

Electronegativity Difference: A single oxygen atom (O) has an electronegativity of 3.44.

The structure of molecule O2 is formed when two of these atoms establish a double bond between themselves (diatomic oxygen). Since two atoms are identical, there is no change in their electronegativity.

Dipole Moment of O2: Since the atoms that make up O2 are identical, they exert an equal and opposite force on each other.

The magnitude of the pull exerted on the shared electrons by both sides is identical, resulting in a net force of zero.

Therefore, no charge accumulation happens at either pole, and the oxygen molecule’s net dipole moment remains 0 Debye.

The linear shape of the O2 molecule is a result of the diatomic molecule. Two atoms establish double bonds to complete their octet and create a linear geometry.

Below is a picture of the oxygen molecule’s geometrical structure.

Nature of the Link in O2: When two oxygen atoms come together to create a bond, they form a covalent double bond, in which valence electrons are shared equally.

Oxygen’s electron configuration is [He] 2s2 2p4. It is evident that there are six valence electrons accessible for bonding in the second shell of the atom.

When two oxygen atoms create a covalent double bond, they share one pair of electrons (i.e., two electrons are shared by each atom).

Due to the uniform distribution of electrons and the absence of partial charges at any of the atoms, the net charge on each atom in the molecule is zero.

Due to the covalent link and the absence of a permanent dipole moment, the diatomic oxygen molecule (O2) is non-polar.

O2 has a Lewis structure.

While determining the Lewis structure of a diatomic oxygen molecule, there are two possible configurations: one with a single bond and the other with a double bond. However, only one of these structures is sufficiently stable to exist.

Despite the fact that both structures (a) and (b) have complete octets for both oxygen atoms, the two structures differ significantly in terms of stability.

On both oxygen atoms in structure (a), an unpaired electron, known as a radical, is present. This radical is extremely chemically reactive and causes the entire structure to become unstable.

In contrast, structure (b) does not include any radicals. The establishment of a double bond maintains the integrity of the octet and stabilises the structure by incorporating the radicals of structure (a) into the bond.

The structure of any element should not only prioritise the completion of the octet, but also stability.

Consequently, the preferred structure for elemental oxygen O2 is (b), which contains a double bond between the two oxygen atoms.

In addition, you must read an article on the O2 Lewis Structure, Molecular Geometry, and Hybridization.

The Most Stable Oxygen Allotrope — O2

O2 is the most stable type of oxygen in existence. It is colourless in its gaseous state and imparts a light blue hue to its liquid and solid states.

The creation of O2 is primarily attributable to photosynthesis, which can be represented by the following equation:

6CO2(Carbon-dioxide) + 6H2O(Water) ——photons(Sunlight) —-> C6H12O6 (Glucose) + 6O2(Oxygen) (Dioxygen)

Occurrence

Oxygen is the most abundant chemical element on the surface of the Earth and the third most abundant element in the universe (after Hydrogen and Helium).

It comprises approximately 49.2% of the mass of the Earth’s crust and 0.9% of the mass of the Sun.

The majority of oxygen is present in oxide molecules, such as silicon dioxide (SiO2).

It is also found as a gas in the atmosphere and in dissolved form in water. Oxygen comprises 88.8 percent of the mass of the world’s seas, whereas it accounts for 20.8% of the volume of the atmosphere.

Qualities of oxygen

Mass moléculaire = 16 g

Density (at standard temperature and pressure/in gaseous state) = 1.43 g/L

Density (in liquid form) = 1.14 grammes per cubic centimetre

Point de fusion = -218.8 °C

Boiling point = -183 °C

At Standard Temperature and Pressure, Oxygen exists as a colourless gas, whereas in liquid form it is pale blue.

It is a highly reactive nonmetal having heats of fusion and vaporisation of 0.44 and 6.82 kJ/mol, respectively.

Pure oxygen weighs 1.1 times as much as air.

With oxidation states -1, -2, and +2, oxygen is the most common oxidising agent (only in compounds with Fluorine).

Oxygen rapidly dissolves in water (more readily in freshwater than seawater).

Oxygen contributes to combustion.

Utilizations of O2

Existence/Breathing: Animals on land, in the air, and in the water must breathe oxygen to survive. It is present in dissolved form in water for fish and other aquatic organisms.

Oxygen supplementation is also utilised in medicine. Oxygen therapy can treat a variety of illnesses, including pneumonia, heart conditions, emphysema, etc.

As a low-pressure breathing gas, it is utilised in astronauts’ space suits for life support. It is also artificially eaten by divers (Scuba and others) via cylinders.

Industrial Application: The process of smelting iron ore to manufacture steel requires approximately half of the oxygen produced commercially. Additionally, it is employed in welding and water treatment facilities.

Oxygen is utilised in a variety of chemical reactions in the chemical industry to produce oxides, polymers, etc.

Formation of Ozone (O3): Ozone is a gaseous substance that occurs naturally in the earth’s atmosphere and shields it from the sun’s UV radiation. An endothermic process using three moles of O2 can produce two moles of O3. 3O2 (Oxygen) ——–> 2O3 (Ozone)

Conclusion

As O2, oxygen forms a diatomic molecule. Each atom forms. Due to their same electronegativity, both atoms exert an equal amount of influence over the charges. The O2 molecule’s dipole moment is 0, indicating that it is a nonpolar molecule.

Friends, if you have any queries on polarity or non-polarity, please let me know. Feel free to contact us through the comment section.

Read more: Is CF2Cl2 a polar or non-polar compound?

Misha Khatri
Misha Khatri is an emeritus professor in the University of Notre Dame's Department of Chemistry and Biochemistry. He graduated from Northern Illinois University with a BSc in Chemistry and Mathematics and a PhD in Physical Analytical Chemistry from the University of Utah.

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