Ammonium nitrite

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Not to be confused with ammonium nitrate.
Ammonium nitrite
Names
IUPAC name
Ammonium nitrite
Systematic IUPAC name
Ammonium nitrite
Other names
Nitrous acid, ammonium salt
Properties
NH4NO2
Molar mass 64.06 g/mol
Appearance Colorless to pale yellow solid
Density 1.69 g/cm3
Melting point 32–33 °C (90–91 °F; 305–306 K)
Boiling point Detonates
Soluble
Solubility Reacts with acids
Hazards
Safety data sheet CPCB
Related compounds
Related compounds
Ammonium nitrate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Ammonium nitrite is an inorganic chemical compound, the ammonia salt of nitrous acid, with the formula NH4NO2. It is not used in pure isolated form, since it is highly unstable and decomposes into water and nitrogen even at room temperature.

Properties

Chemical

Ammonium nitrite decomposes even at room temperature to release nitrogen gas.

NH4NO2 → N2 + 2 H2O

Physical

Ammonium nitrite is a yellow to colorless solid, soluble in water.

Explosive

Ammonium nitrite explodes if heated above 60–70 °C, and will decompose quicker when dissolved in a concentrated aqueous solution, than in the form of a dry crystal

Availability

Ammonium nitrite is extremely difficult to find, and almost no big chemical supplier has it in their stock.

One supplier sells a 20% aq. solution of this compound.

Preparation

Adding ammonium sulfate to barium or lead(II) nitrite will precipitate their respective sulfates, while leaving ammonium nitrite in solution. The reaction between silver nitrite and ammonium chloride will work in the same way.

Ammonium nitrite can be prepared by the absorption of equal parts nitrogen dioxide and nitric oxide in aqueous ammonia.

Other routes involve oxidizing ammonia with ozone or hydrogen peroxide.

The resulting ammonium nitrite obtained is in aqueous form. Heating the solution to dry the compound will cause it to decompose and high concentrations it may explode. To obtain the solid compound, you will have to cool the solution until the ammonium nitrite precipitates out of the solution. To limit decomposition, you will have to maintain its pH above 7, which can be easily done by adding an excess of ammonia.

Projects

  • Make nitrogen gas
  • Synthesis of ammonium cobalti-nitrite

Handling

Safety

Ammonium nitrite is unstable and heating it may cause it to explode.

Storage

It is not stable to store this compound in pure form, while aqueous solutions should not be stored for long periods of time. Keep them at high pH and at low temperatures.

Disposal

Can be easily neutralized by adding a base like sodium hydroxide or sodium percarbonate, though ammonia will be released from the neutralization. Do not add acid to neutralize the ammonia, as the leftover ammonium nitrite may decompose violently.

References

Relevant Sciencemadness threads