Aluminium carbonate
Chemical compound
From Wikipedia, the free encyclopedia
Aluminium carbonate (Al2(CO3)3), is a carbonate of aluminium. It is not well characterized; one authority[which?] says that simple carbonates of aluminium are not known.[2] However, related compounds are known, such as the basic sodium aluminium carbonate mineral dawsonite (NaAlCO3(OH)2) and hydrated basic aluminium carbonate minerals scarbroite (Al5(CO3)(OH)13•5(H2O)) and hydroscarbroite (Al14(CO3)3(OH)36•nH2O).[3][4][5]
| Names | |
|---|---|
| IUPAC name
Dialuminium Tricarbonate | |
| Identifiers | |
3D model (JSmol) |
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| ChemSpider | |
| ECHA InfoCard | 100.034.930 |
PubChem CID |
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| UNII | |
CompTox Dashboard (EPA) |
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| Properties | |
| Al2(CO3)3 | |
| Molar mass | 233.99 g/mol |
| Appearance | white powder, unstable |
| Density | 3.14 g/cm3 |
| reacts | |
| Structure[1] | |
| orthorhombic | |
| Fdd2 | |
a = 21.989 Å, b = 10.176 Å, c = 4.4230 Å | |
Lattice volume (V) |
989.7 |
Formula units (Z) |
8 |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Preparation
For many years there was no evidence for the existence of a simple aluminium carbonate, Al2(CO3)3, as the combination of Al3+ and carbonates are sufficiently alkaline to precipitate aluminium hydroxide and produce carbon dioxide:[6]
![{\displaystyle {2\,[\mathrm {Al} (\mathrm {H} {\vphantom {A}}_{\smash[{t}]{2}}\mathrm {O} ){\vphantom {A}}_{\smash[{t}]{6}}]{\vphantom {A}}^{3+}{\mskip {2mu}}(\mathrm {aq} ){}+{}3\,\mathrm {CO} {\vphantom {A}}_{\smash[{t}]{3}}{\vphantom {A}}^{2-}{\mskip {2mu}}(\mathrm {aq} ){}\mathrel {\longrightarrow } {}2\,\mathrm {Al} (\mathrm {OH} ){\vphantom {A}}_{\smash[{t}]{3}}{\mskip {2mu}}(\mathrm {s} ){}+{}3\,\mathrm {CO} {\vphantom {A}}_{\smash[{t}]{2}}{\mskip {2mu}}(\mathrm {g} ){}+{}9\,\mathrm {H} {\vphantom {A}}_{\smash[{t}]{2}}\mathrm {O} {\mskip {2mu}}(\mathrm {l} )}}](http://wikimedia.org/api/rest_v1/media/math/render/svg/27e6891912209f89743b0ae468dbd3a1d54ce4d3)
However, in 2023, Al2(CO3)3 was produced by heating aluminium oxide at 2300 °C under 24 GPa of carbon dioxide. The resulting solid is stable in air and at room temperature.[7]
Some minerals contain both aluminium and carbonate. Dawsonite has the formula NaAlCO3(OH)2. Hydrotalcites, both synthetic and natural, are layered metal hydroxides comprised in part of aluminium and carbonate.[8]
Surface carbonate species readily form upon exposure of aluminium oxide to CO2.[9]