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Other names
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Identifiers | |
3D model (JSmol)
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ChemSpider | |
ECHA InfoCard | 100.029.141 |
EC Number |
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E number | E523 (acidity regulators, ...) |
KEGG |
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PubChem CID
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RTECS number |
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UNII |
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CompTox Dashboard (EPA)
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Properties[1] | |
(NH4)Al(SO4)2 | |
Molar mass | 237.15 g/mol (anhydrous) 453.33 g/mol (dodecahydrate) |
Appearance | white crystals |
Density | 2.45 g/cm3 (anhydrous) 1.64 g/cm3 (dodecahydrate) |
Melting point | 93.5 °C (200.3 °F; 366.6 K) (dodecahydrate) |
Boiling point | 120 °C (248 °F; 393 K) dehydr. (dodecahydrate) |
15 g/100 ml (20 °C, dodecahydrate) | |
Structure[1] | |
Hexagonal (anhydrous) Cubic (dodecahydrate) | |
Octahedral (Al3+) | |
Hazards[2] | |
GHS labelling: | |
Warning | |
H315, H319 | |
P264, P280, P302+P352, P305+P351+P338, P321, P332+P313, P337+P313, P362 | |
Flash point | Non-flammable |
Safety data sheet (SDS) | External MSDS |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Ammonium aluminium sulfate, also known as ammonium alum or just alum (though there are many different substances also called "alum"), is a white crystalline double sulfate usually encountered as the dodecahydrate, formula (NH4)Al(SO4)2·12H2O. It is used in small amounts in a variety of niche applications. The dodecahydrate occurs naturally as the rare mineral tschermigite.[1]