Is Nitrogen Flammable? (And Why?)

Nitrogen gas (N₂) is not flammable gas that does not react with other elements or compounds under normal conditions. This means that it does not support combustion and is not itself flammable. ¹

Well, this was just a simple answer. But there are few more things to know about this topic which will make your concept super clear.

So let’s dive right into it.

Why is nitrogen not flammable?

Nitrogen gas (N2) is not flammable because it is a chemically stable, non-reactive element under normal conditions. Nitrogen atoms are held together by very strong triple covalent bonds, which require a large amount of energy to break apart. ²

In order for a substance to be flammable, it needs to be able to react with oxygen in the air to produce heat and light. Nitrogen gas does not readily react with oxygen at normal temperatures and pressures, so it cannot sustain a combustion reaction. ^{3 4}

However, nitrogen can support combustion indirectly, as it can act as an inert gas to displace oxygen and prevent a fire from burning. This is why nitrogen gas is often used in fire suppression systems, such as in chemical and industrial plants. ⁵

Is liquid nitrogen flammable?

No, liquid nitrogen is not flammable. Like its gaseous form, nitrogen in its liquid state is non-flammable. In fact, liquid nitrogen is actually used as a coolant for materials that need to be kept at very low temperatures, such as in scientific research, cryogenic preservation, and some industrial processes. ^{6 7}

Although liquid nitrogen itself is not flammable, it can pose a hazard if it is stored or used improperly. ⁸

When liquid nitrogen is exposed to air, it rapidly evaporates and produces a large amount of nitrogen gas. If the gas is not vented properly, it can displace oxygen in the air and create an oxygen-deficient atmosphere, which can be dangerous for humans and animals.

Additionally, if liquid nitrogen comes into contact with certain materials, such as some metals, plastics, or rubber, it can cause them to become brittle and break. This can pose a hazard if these materials are under stress or are part of a larger system, such as in machinery or equipment.

Therefore, it is important to handle and store liquid nitrogen with proper safety measures and training.

Difference between nitrogen and other flammable gases

The main difference between nitrogen and other flammable gases is that nitrogen is not reactive under normal conditions, whereas other flammable gases, such as methane, propane, and hydrogen, are highly reactive and can easily combust when exposed to a spark or flame. ^{9 10}

Nitrogen’s stable triple covalent bonds make it a chemically inert gas, meaning it does not easily form compounds with other elements.

In contrast, flammable gases have weaker bonds and are more likely to react with oxygen in the air, producing heat and light in a combustion reaction. Additionally, flammable gases often have a lower ignition temperature, meaning they can ignite and sustain a fire at lower temperatures than nitrogen.

Another difference is that nitrogen is an essential component of the Earth’s atmosphere, making up about 78% of the air we breathe. ^{11 12 13}

Flammable gases are generally present in much lower concentrations and are often produced as byproducts of industrial processes, such as refining oil or natural gas.

Finally, nitrogen is often used as an inert gas to prevent fires or explosions, whereas flammable gases are used as fuel for combustion reactions.

Nitrogen’s non-reactive nature makes it useful for displacing oxygen in industrial processes and preventing oxidation of materials, whereas flammable gases are used to generate heat or power.

Further reading

Is Chlorine Flammable?
Why is Fluorine Diatomic?
Why is Bromine Diatomic?
Why is Oxygen Diatomic?
Is Sulfur Diatomic? 

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