Nitrogen Trioxide N2O3 Structure Properties and Reactions Explained

Nitrogen trioxide (molecular formula N₂O₃) is a chemical compound formed by mercury and chlorine. It is also known as dinitrogen trioxide or nitrogen sesquioxide. The compound is highly toxic and irritates the mucous membranes. Nitrogen trioxide is a blue liquid accompanied by a sharp and unpleasant chemical odour. Density 1.447 g / cm³. Due to the low-boiling point of 3.5 degrees C, the compound is held as a liquid by compression. Partially dissociates into NO and NO₂. Strong irritant to skin, eyes and mucous membranes. Vapours are very toxic by inhalation. They are used in special-purpose fuels. The prolonged exposure to heat may cause the container to rupture violently and burst out.

\[NO + NO_{2} \rightleftarrows N_{2}O_{3}\]

Properties of Nitrogen Trioxide N2O3

Nitrogen trioxide (molecular formula N₂O₃) has a molecular weight of 76.012 g / mol and a density of 1.447 g / cm³. It has a hydrogen bond donor count of 0 while the hydrogen bond donor count is 4. The boiling point and melting point of nitrogen trioxide is 3.5 degrees Celsius  and -100.7 degree Celsius.

Some other properties of nitrogen trioxide N₂O₃ are mentioned below:

XLogP₃-AA – -0.1

Rotatable Bond Count - 0

Exact mass - 75.990892 g / mol

Monoisotopic Mass - 75.990892 g / mol

Topological Polar Surface Area - 75.2 Ų

Heavy Atom Count – 5

Complexity – 50.4

Covalently-Bonded Unit Count – 1

Compound Is Canonicalized – Yes

Solubility in water – Yes

Uses of Nitrogen Trioxide

Properties of Nitrogen Trioxide N₂O₃ is used in the following ways:

• Due to its highly explosive nature, it is used as a particular fuel.

• It supports the only combustion and only helps in burning, but does not burn itself which may ignite substances like wood, paper, oil, clothing, etc.

• It is a powerful oxidizer.

• It is combined with other chemical compounds to be used as an oxidizing agent.

• It is also used in the chemical industry, such as in making nylon, dyes, etc.

Structure of Nitrogen Trioxide

Nitrogen – nitrogen (N – N) bonds are almost the same in length as that in hydrazine, that is, 145 pm.  However, Dinitrogen trioxide has a long N–N bond of 186 pm, which is unusual. Some nitrogen oxides contain long N–N bonds, which include dinitrogen tetroxide (175 pm). The Nitrogen Trioxide molecule has a planar structure and exhibits Cs symmetry. 

It produces unstable nitrous acid (HNO₂) when mixed into water. An alternative structure for the true anhydride, i.e. O=N–O–N=O, but this isomer is not observed. If the nitrous acid produced is not used up quickly, then it decomposes into nitric oxide and nitric acid. Sometimes, nitrite salts are produced by adding N₂O₃ to solutions of some bases like NaOH.

(Image will be uploaded soon)

Handling and Storage

For non-fire spills and leaks, fully encapsulating, vapour-protective garments should be worn. It is not advisable to touch or walk over spilling material. Keep flammables (oil, wood, paper, etc.) away from the spilt substance. If you can do so without putting yourself in danger, stop the leak. To minimize vapours or deflect vapour cloud drift, use water spray. Allowing water runoff to come into touch with spilt substances is not a good idea. Water should not be directed at the spill or the source of the leak. If at all possible, flip leaky containers so that gas instead of liquid escapes. Prevent access to rivers, sewers, basements, and other restricted locations. Isolate the area till the gas has passed. Make certain that the area is adequately ventilated.

Personal Protection and Exposure Control

Wear self-contained breathing equipment with positive pressure (SCBA). Wear chemical protection clothes that the manufacturer has particularly suggested. It may or may not give any heat protection. Protective apparel worn by structural firefighters provides very limited protection in fire circumstances; it is ineffective in spill scenarios when direct contact with the chemical is possible.

Fire Fighting Measures

These items do not burn but will aid in the combustion process. Allow the fire to burn without being extinguished. If fire must be extinguished, it is best to use water spray or fog. Only water; no dry chemicals, CO₂, or Halon®. Make sure that water doesn’t enter the containers. Move containers away from the fire zone if you can do so safely. Damaged cylinders should only be handled by experts. Fight fires from as far away as possible or utilize unmanned hose holders or monitor nozzles. Cool containers with large amounts of water until the fire has been extinguished. Water should not be directed at the source of the leak or safety devices; icing may develop. Withdraw immediately if there is a rising sound from the venting safety mechanisms or if the tank is discoloured. Always keep a safe distance from engulfed-in-fire tanks. For severe flames, use unmanned hose holders or monitor nozzles; if this isn't possible, just leave the area and let the fire burn.

Solved Examples

Q. Nitrogen Trioxide (N₂O₃) is/has a _ While Nitrogen Dioxide (NO₂ ) is/has a _.

a. Brown gas, Blue gas

b. Colourless solid, brown gas

c. Colourless solid, colourless gas

d. Blue solid, Brown gas

Solution:

Dinitrogen trioxide (N₂O₃ ) is solid in blue colour. Nitrogen has an oxidation number of +3 while NO₂ is gas in brown colour. The oxidation number of nitrogen in the compound is +4. Therefore, the answer is 4.

Q. Assertion: N₂O₃ is Less Basic than P₂O₃.

Reason: As we go down the group, the metallic nature increases. 

a. The reason is the correct explanation of assertion and both assertion and reason are true.

b. The reason is not the correct explanation of assertion and both assertion and reason are true.

c. The reason is false and the assertion is true.

d. The assertion is not true and the reason is true.

Solution: When we go down the group, atomic radius increases, due to this ionization energy decreases and hence a tendency to lose electrons also increases (i.e., the metallic character is increased).

Since metallic characters increase down the group, the basicity increases down the group.

Hence the order of basicity is N₂O₃ <P₂O₃. 

Therefore, the answer is 1.

Q. What is the Chemical Formula of Nitrogen Trioxide?

Solution: The chemical formula of nitrogen trioxide is N₂O₃.