Ammonium carbonate
- Ammonium carbonate
- Hirschhornsalz
- Diammonium
- E 503i
- 506-87-6
- 10361-29-2
Hygroscopic colorless solid with ammoniacal odor
Fixed
1.6 g · cm -3 ( at 20 ° C)
Decomposition above 58 ° C
69 hPa ( 20 ° C)
Well in water (320 g · l -1)
Attention
1975 mg · kg -1 ( LD50, rat, oral)
-942 KJ · mol -1
Template: Infobox chemical / molecular formula search available
Ammonium carbonate, ( NH4) 2CO3 · H2O, forms water- soluble, colorless, cubic crystals. It decomposes at 58 ° C completely into ammonia, carbon dioxide and water. It represents a 1:1 mixture of ammonium bicarbonate and ammonium carbamate
Properties
The salt forms a colorless, smelling faintly of ammonia powder. It has a density of 1.6 g · cm -3 ( at 20 ° C). In aqueous solution, it reacts weakly basic, it provides a balance between ammonia NH3, NH4 ammonium ions, carbonate ions, CO32 -, HCO3- hydrogen carbonate ions and carbon dioxide CO2 a. The pH of a 10 % aqueous solution at 25 ° C is 9.4.
Thus, the salt reacts with water and carbon dioxide to hydrogen and hydroxide ions. An aqueous solution of ammonium carbonate is therefore only stable in neutral and weakly alkaline environment - in acids escaping carbon dioxide in caustic solutions, ammonia gas.
Ammonium carbonate decomposes in the air, in the heat, the reaction is carried out violently.
Production and representation
The preparation of ammonium carbonate can be prepared by reacting carbon dioxide with ammonia in aqueous solution.
Another possible result by heating calcium carbonate together with ammonium sulfate.
In the latter method sublimated from next to the desired ammonium carbonate ammonium carbonate and ammonium carbamate even when solid remains calcium sulfate.
Use
Ammonium carbonate is used in the synthesis of heterocycles, and as an additive photographic developers. Likewise, it finds in dyeing as a mordant, as spotting and as carbon dioxide extinguishers developers in use.
In addition, it is used as a leavening agent (as part of hartshorn ). In the EU it is approved as a food additive E number of the 503i.
It has also been held earlier than smelling salts to revive in dizziness and fainting under his nose.
Ammonium carbonate is often used in the field of inorganic chemistry for qualitative analysis, in order to precipitate the cation separation transition from an unknown sample of the alkaline earth metal is barium, strontium and calcium as a group to separate and identify by means of detection reactions.
Furthermore, it is used for preparing catalysts, foam, hair-treatment compositions and casein colors and glue.