Ammonium carbonate

Ammonium carbonateis achemical compoundwith thechemical formula[NH4]2CO3. It is anammoniumsaltofcarbonic acid. It is composed of ammoniumcations[NH4]andcarbonateanionsCO2−3. Since ammonium carbonate readily degrades to gaseous ammonia and carbon dioxide upon heating, it is used as aleavening agentand also assmelling salt. It is also known asbaker's ammoniaand is a predecessor to the more modern leavening agentsbaking sodaandbaking powder. It is a component of what was formerly known assal volatileandsalt ofhartshorn,and produces a pungent smell when baked. It comes in the form of a white powder or block, with amolar massof 96.09 g/mol and a density of 1.50 g/cm. It is a strongelectrolyte.
Ammonium carbonate is produced by combining carbon dioxide and aqueous ammonia. About 80,000 tons/year were produced as of 1997.
An orthorhombic ammonium carbonate monohydrate is known ([NH4]2CO3·H2O). It crystallizes in an ammonia solution exposed in a carbon dioxide-rich atmosphere.
Ammonium carbonate slowly decomposes atstandard temperature and pressurethrough two pathways. Thus any initially pure sample of ammonium carbonate will soon become a mixture including various byproducts.
Ammonium carbonate can spontaneouslydecomposeintoammonium bicarbonateandammonia:
Which further decomposes tocarbon dioxide,waterand another molecule ofammonia:
Ammonium carbonate may be used as aleavening agentin traditional recipes, particularly those from northern Europe and Scandinavia (e.g.Amerikaner,Speculoos,TunnbrödorLebkuchen). It was the precursor to today's more commonly used baking powder.
Originally made from ground deer horn and called hartshorn, today it is called baker's ammonia. It is prepared by the sublimation of a mixture of ammonium sulfate and calcium carbonate and occurs as a white powder or a hard, white or translucent mass.It acts as a heat activated leavening agent and breaks down into carbon dioxide (leavening), ammonia (which needs to dissipate) and water. It is sometimes combined with sodium bicarbonateto mimic as adouble acting baking powder and to help mask any ammonia smell not baked out.
It also serves as anacidity regulatorand has theE numberE503. It can be replaced with baking powder, but this may affect both the taste and texture of the finished product. Baker's ammonia should be used to create thin dry baked goods like crackers and cookies. This allows the strong ammonia smell to bake out. It should not be used to make moist baked items like cake since ammonia is hydrophilic and will leave a strong bitter taste.
Its use as a leavening agent, with associated controversy, goes back centuries:
Ammonium carbonate is the main component ofsmelling salts, although the commercial scale of their production is small.Buckley'scough syrup from Canada today uses ammonium carbonate as an active ingredient intended to help relieve symptoms of bronchitis. It is also used as anemetic. It is also found in smokeless tobacco products, such as Skoal, and it is used in aqueous solution as a photographic lens cleaning agent, such as Eastman Kodak's "Kodak Lens Cleaner."
It is also used forluringofapple maggotsinWashington State, to monitor the spread of the infestation and adjust the borders of theApple Maggot Quarantine Area.