Ammonium sulfite

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Not to be confused with ammonium sulfide or ammonium bisulfite.
Ammonium sulfite
IUPAC name
Ammonium sulfite
Other names
Ammonium sulphite
Diammonium sulfite
Diammonium sulfonate
Diazanium sulfite
Sulfurous acid, diammonium salt
(NH4)2SO3 (anhydrous)
(NH4)2SO3·H2O (monohydrate)
Molar mass 116.14 g/mol
Appearance Whitish hygroscopic solid
Odor Odorless
Density 1.41 g/cm3 (at 25 °C)
Melting point 65 °C (149 °F; 338 K) (decomposes)
Boiling point Decomposes
32.4g/100ml (at 0 °C)
35.0 g/100 ml (at 20 °C)
60.4g/100ml (at 100 °C)
Solubility Reacts with acids
Insoluble in acetone, ethanol, toluene
Safety data sheet Sigma Aldrich (monohydrate)
Flash point Non-flammable
Related compounds
Related compounds
Ammonium bisulfite
Ammonium sulfate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Ammonium sulfite is a colorless hygroscopic salt of ammonia with the formula (NH4)2SO3.



Ammonium sulfite is slowly oxidized to ammonium sulfate in open air.

(NH4)2SO3 + ½ O2 → (NH4)2SO4

Addition of a strong acid will release sulfur dioxide:

(NH4)2SO3 + 2 HCl → 2 NH4Cl + SO2 + H2O


Ammonium sulfite is a colorless hygroscopic solid, soluble in water but insoluble in organic solvents.


Some hair straightening and waving products contain ammonium sulfite. It can also be found on Amazon.

Lastly it can also be bought from suppliers.


Like most sulfites, ammonium sulfite can be made by bubbling sulfur dioxide through a cold solution of excess ammonia.


  • Reducing agent
  • Make ammonium sulfate



Ammonium sulfite has low toxicity, though it can be irritant on contact.


In sealed bottles, away from air or acids.


Leaving it in open air will convert it in ammonium sulfate. Bleach or hydrogen peroxide can also be used to accelerate the reaction. The resulting ammonium sulfate can be poured down the drain, thrown in the trash or dumped in ground.


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