Ammonium carbonate is a

chemical compound A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element ...

with the

chemical formula A chemical formula is a way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbols, such as pare ...

. It is an

ammonium Ammonium is a modified form of ammonia that has an extra hydrogen atom. It is a positively charged (cationic) polyatomic ion, molecular ion with the chemical formula or . It is formed by the protonation, addition of a proton (a hydrogen nucleu ...

salt In common usage, salt is a mineral composed primarily of sodium chloride (NaCl). When used in food, especially in granulated form, it is more formally called table salt. In the form of a natural crystalline mineral, salt is also known as r ...

carbonic acid Carbonic acid is a chemical compound with the chemical formula . The molecule rapidly converts to water and carbon dioxide in the presence of water. However, in the absence of water, it is quite stable at room temperature. The interconversion ...

. It is composed of ammonium

cations An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by convent ...

and

carbonate A carbonate is a salt of carbonic acid, (), characterized by the presence of the carbonate ion, a polyatomic ion with the formula . The word "carbonate" may also refer to a carbonate ester, an organic compound containing the carbonate group ...

anions An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by convent ...

. Since ammonium carbonate readily degrades to gaseous ammonia and carbon dioxide upon heating, it is used as a

leavening agent In cooking, a leavening agent () or raising agent, also called a leaven () or leavener, is any one of a number of substances used in doughs and batters that cause a foaming action (gas bubbles) that lightens and softens the mixture. An altern ...

and also as smelling salt. It is also known as baker's ammonia and is a predecessor to the more modern leavening agents

baking soda Sodium bicarbonate (IUPAC name: sodium hydrogencarbonate), commonly known as baking soda or bicarbonate of soda (or simply “bicarb” especially in the UK) is a chemical compound with the formula NaHCO3. It is a salt (chemistry), salt compose ...

and

baking powder Baking powder is a dry chemical leavening agent, a mixture of a carbonate or bicarbonate and a weak acid. The base and acid are prevented from reacting prematurely by the inclusion of a buffer such as cornstarch. Baking powder is used to increas ...

. It is a component of what was formerly known as sal volatile and salt of hartshorn, and produces a pungent smell when baked. It comes in the form of a white powder or block, with a

molar mass In chemistry, the molar mass () (sometimes called molecular weight or formula weight, but see related quantities for usage) of a chemical substance ( element or compound) is defined as the ratio between the mass () and the amount of substance ...

of 96.09 g/mol and a density of 1.50 g/cm³. It is a strong

electrolyte An electrolyte is a substance that conducts electricity through the movement of ions, but not through the movement of electrons. This includes most soluble Salt (chemistry), salts, acids, and Base (chemistry), bases, dissolved in a polar solven ...

Production

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 (). It crystallizes in an ammonia solution exposed in a carbon dioxide-rich atmosphere.

Decomposition

Ammonium carbonate slowly decomposes at

standard temperature and pressure Standard temperature and pressure (STP) or standard conditions for temperature and pressure are various standard sets of conditions for experimental measurements used to allow comparisons to be made between different sets of data. The most used ...

through two pathways. Thus any initially pure sample of ammonium carbonate will soon become a mixture including various byproducts. Ammonium carbonate can spontaneously

decompose Decomposition is the process by which dead organic substances are broken down into simpler organic or inorganic matter such as carbon dioxide, water, simple sugars and mineral salts. The process is a part of the nutrient cycle and is essen ...

into

ammonium bicarbonate Ammonium bicarbonate is an inorganic compound with formula (NH4)HCO3. The compound has many names, reflecting its long history. Chemically speaking, it is the bicarbonate salt of the ammonium ion. It is a colourless solid that degrades readily to ...

and

ammonia Ammonia is an inorganic chemical compound of nitrogen and hydrogen with the chemical formula, formula . A Binary compounds of hydrogen, stable binary hydride and the simplest pnictogen hydride, ammonia is a colourless gas with a distinctive pu ...

: : Which further decomposes to

carbon dioxide Carbon dioxide is a chemical compound with the chemical formula . It is made up of molecules that each have one carbon atom covalent bond, covalently double bonded to two oxygen atoms. It is found in a gas state at room temperature and at norma ...

water Water is an inorganic compound with the chemical formula . It is a transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance. It is the main constituent of Earth's hydrosphere and the fluids of all known liv ...

and another molecule of

: :

Uses

Leavening agent

Ammonium carbonate may be used as a

in traditional recipes, particularly those from northern Europe and Scandinavia (e.g. Amerikaner, Speculoos,

Tunnbröd Tunnbröd (; literally 'thinbread') is a Swedish version of flatbread. Tunnbröd can be soft or crisp, and comes in many variants depending on choice of grain, leavening agent (or lack thereof) and rolling pin. The dough is made from any combin ...

Lebkuchen (), or () are honey-sweetened German cuisine, German cakes, moulded cookies or bar cookies that have become part of Germany's Christmas traditions. They are similar to gingerbread. Etymology The etymology of ''Leb-'' in the term is unc ...

). 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 bicarbonate double acting baking powder and to help mask any ammonia smell not baked out. It also serves as an

acidity regulator Acidity regulators, or pH control agents, are food additives used to change or maintain pH ( acidity or basicity). They can be organic or mineral acids, bases, neutralizing agents, or buffering agents. Typical agents include the following ac ...

and has the

E number E numbers, short for Europe numbers, are codes for substances used as food additives, including those found naturally in many foods, such as vitamin C, for use within the European Union (EU) and European Free Trade Association (EFTA). Commonly ...

E503. 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:

Other uses

Ammonium carbonate is the main component of smelling salts, although the commercial scale of their production is small. Buckley's cough syrup from Canada today uses ammonium carbonate as an active ingredient intended to help relieve symptoms of bronchitis. It is also used as an

emetic Vomiting (also known as emesis, puking and throwing up) is the forceful expulsion of the contents of one's stomach through the mouth and sometimes the nose. Vomiting can be the result of ailments like food poisoning, gastroenteritis, preg ...

. 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 for luring of apple maggots in

Washington State Washington, officially the State of Washington, is a state in the Pacific Northwest region of the United States. It is often referred to as Washington State to distinguish it from the national capital, both named after George Washington ...

, to monitor the spread of the infestation and adjust the borders of the Apple Maggot Quarantine Area.

References