Is NO3 a polar or nonpolar substance?

Because one of the three N-O linkages has a double bond, NO3 (Nitrate) is a tetrahedral compound with trigonal planar molecular geometry, making it a stable chemical. Because nitrates are very soluble and biodegradable in nature, they are one of the most often utilised fertilisers.

Because nitrate’s toxicity level is low, there has been a lot of debate concerning the risk of long-term nitrate exposure. It may surprise you to learn that while nitrate (NO3) is not toxic to humans, it is a precursor to acid rain.

The following are the atmospheric reactions to the same:

NO2    +    O3    ——>     NO3    +    O2
NO2    +    NO3    +   (M)     <==>      N2O5
N2O5    +    H2O(s)    —–>     2 HNO3
NO2    +    OH    +     M     —–>   HNO3    +    M

Students are often thinking about their polarity behaviour when studying the molecular geometry of nitrate. Because nitrate (NO3) is an exception to the norms of polarity molecules, despite possessing a double bond and covalent sharing of valence electrons.

The following is an example of an exception:

Is NO3 polar or non-polar, then? NO3 is a non-polar molecule due to its symmetrical shape, which cancels out any dipole moments inside the molecule despite the existence of a double bond. There will be no separation of charges between the two ends of the molecule since there is no net dipole moment, and thus no polarity.

Why is NO3 a polar molecule?

Despite the presence of a double bond, the non-polar behaviour of NO3 perplexes many students. To fully comprehend this issue, we must first examine the Lewis structure of NO3.

Regardless of whether one of the three N-O bonds has a double bond, all three N-O bonds are positioned at an identical distance from one another, resulting in a three-dimensional structure that is symmetrical.

The three symmetrical bonds and the 120° O-N-O bond angle give birth to trigonal planar symmetry, according to the valence shell electron pair repulsion theory (VSEPR).

As a result, the NO3 molecule is symmetrical, which makes it non-polar because there is no charge separation in a symmetrical molecule.

What are the differences between polar and non-polar molecules?

Polar molecules are asymmetrical molecules with electric poles, which create charge separation at their ends. The positive charge is collected on one end, while the negative charge is collected on the other.

This charge separation forces the molecule to use hydrogen bonds to powerfully attract other polar molecules nearby.

Furthermore, the net dipole moment on the molecule is generated by this charge separation, making it highly reactive.

Water is one of the best examples of polar molecules (H2O). Read the polarity of H2O out loud.

Non-polar molecules, on the other hand, are symmetrical molecules without electric poles, resulting in no charge separation at the ends. Non-polar molecules lack electric poles as a result, and a weak Van der Waal interaction is produced in order to establish bonds with other molecules.

The net dipole moment remains zero due to the establishment of weak bonds and the lack of charge distribution, rendering non-polar molecules weakly reactive.

Oil is one of the most well-known non-polar molecules, as it does not mix well with virtually anything.

Take a look at the article about Oil’s Polarity.

What distinguishes NO3 as a nonpolar molecule?

The presence of a negative charge on the overall NO3 molecule causes the molecule to be non-polar.

Despite the fact that there are three identical N-O bonds, a delocalized electron system exists due to the combination of formal charges of -2/3 of a charge for oxygen and +1 of a charge for nitrogen.

When all charges are added together, (3* -2/3) + 1 = -1, the formal negative charge on one nitrate ion is -1, making the NO3 molecule non-polar in nature.

Atomic electronegativity in nitrate (NO3)

Electronegativity is a mathematical measurement of an atom’s ability to attract shared electrons to itself.

The electronegativity of an atom is exactly proportional to both its atomic number and the distance at which valence electrons are available, because the atom’s ability to attract is determined by its atomic number and the distance at which valence electrons are available.

This means that the higher the electronegativity number, the more shared electrons the atom will attract.

The electronegativity value tends to be lower because non-polar molecules do not draw shared electrons toward themselves.

The electronegativity difference between the two participating atoms in non-polar compounds must be less than 0.5.

The electronegativity of nitrogen is 3.04 and that of oxygen is 3.44 in the case of nitrate (NO3). The difference in the two readings is 0.4, which is less than 0.5, indicating that the NO3 molecule is non-polar.

Why does NO3 have a covalent bond rather than being ionic?

Ionic bonds are created when a metal provides valence electrons to a non-metal and the non-metal takes them.

Covalent bonds, on the other hand, are formed between two non-metals in which both molecules share valence electrons.

Because of the shared pair of valence electrons, covalent bonds usually have some polarity. However, nitrate (NO3) is an exception since, in addition to having covalent connections, it is a non-polar molecule.

It can be observed from the above-mentioned Lewis structure that there is no complete transfer of valence electrons between the involved atoms of nitrogen and oxygen.

The NO3 molecule forms a covalent connection due to the sharing of valence electrons. When two atoms form an ionic bond, one loses all of its valence electrons and becomes a positively charged cation, while the other absorbs all of its valence electrons and becomes a negatively charged anion.

Because this scenario does not exist in the nitrate (NO3) molecule, a covalent link is formed. It might be interesting to learn that the polar behaviour of the nitrate (NO3) can be determined solely by looking at the type of bond formation.

How can you tell if a molecule is polar or not?

The polarity idea applies to covalent bonding and can be verified by looking at a molecule’s electronegativity value (which must be less than 0.4 to be non-polar).

Another approach is to investigate molecular geometry using the valence shell electron pair repulsion theory (VSEPR) theory, which aids in the determination of structure and bond angle.

The importance of nitrate in industry (NO3)

Despite the fact that nitrates are naturally occurring and pose the least harm to humans, they are used to produce explosives such as gun powder, where the explosion causes the oxidation of carbon and its compounds, releasing a significant number of gases.

Furthermore, because nitrates are extremely biodegradable and can combine with air gases to generate another chemical, they are employed as possible fertilisers in agriculture.

News about nitrate (NO3)

Because nitrate (NO3) is a precursor to acid rain, it is a major cause of rock weathering all around the world.

Because of the acid rain, it was recently discovered that the dual isotopic compositions of 15N NO3- and 18O-NO3- from the rainfall entered the groundwater.


The existence of a negative formal charge on the molecule makes nitrate (NO3) a non-polar molecule.

No polar ends form on the NO3 molecule as a result of its negative charge, and the molecule does not attract any other polar molecule.

This is supported by the valence shell electron pair repulsion theory (VSEPR), which states that the molecular geometry of the NO3 molecule is trigonal planar with a 120° O-N-O bond angle. Only non-polar molecules can result from such a configuration.

Read more: Steps To Draw The Silicon Bohr Model

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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