Aluminium carbonate is a carbonate

Carbonate

In chemistry, a carbonate is a salt of carbonic acid, characterized by the presence of the carbonate ion, . The name may also mean an ester of carbonic acid, an organic compound containing the carbonate group C2....

 of aluminium

Aluminium

Aluminium or aluminum is a silvery white member of the boron group of chemical elements. It has the symbol Al, and its atomic number is 13. It is not soluble in water under normal circumstances....

. It is a component of the mineral strontiodesserite.

Aluminium carbonate is an unstable compound, decomposing to aluminium hydroxide

Aluminium hydroxide

Aluminium hydroxide, Al3, ATH, sometimes erroneously called Hydrate of alumina, is found in nature as the mineral gibbsite and its three, much more rare forms, polymorphs: bayerite, doyleite and nordstrandite. Closely related are aluminium oxide hydroxide, AlO, and aluminium oxide, Al2O3,...

 (Al(OH)₃) and carbon dioxide

Carbon dioxide

Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...

 (CO₂):

Al₂(CO₃)₃ + 3 H₂O → 2 Al(OH)₃ + 3 CO₂

It is formed in the reaction between an aluminium compound, such as aluminium sulfate

Aluminium sulfate

Aluminium sulfate, alternatively spelt aluminum sulfate, aluminium sulphate, or aluminum sulphate; is a chemical compound with the formula Al23...

 (Al₂(SO₄)₃), and sodium carbonate

Sodium carbonate

Sodium carbonate , Na2CO3 is a sodium salt of carbonic acid. It most commonly occurs as a crystalline heptahydrate, which readily effloresces to form a white powder, the monohydrate. Sodium carbonate is domestically well-known for its everyday use as a water softener. It can be extracted from the...

(Na₂CO₃):

Al₂(SO₄)₃ + 3 Na₂CO₃ → Al₂(CO₃)₃ + 3 Na₂SO₄

Aluminium carbonate readily decomposes into carbon dioxide and aluminium hydroxide, which is exploited by many fire extinguishers due to the inert nature of the carbon dioxide.