Ammonium alum

Ammonium alum
Names
	Other names Ammonium alum sulfate; Tschermigite;
Identifiers
CAS Number	7784-25-0 ; 7784-26-1 (dodecahydrate) ;
3D model (JSmol)	Interactive image;
ChemSpider	2297489 ; 56419 (dodecahydrate) ;
ECHA InfoCard	100.029.141
EC Number	232-055-3 616-522-2 (dodecahydrate);
E number	E523 (acidity regulators, ...)
KEGG	D02842 (dodecahydrate);
PubChem CID	3032540; 62668 (dodecahydrate);
RTECS number	WS5640010;
UNII	DPU64XYB1D ; 5C36DRL9ZN (dodecahydrate) ;
CompTox Dashboard (EPA)	DTXSID7051428 ;
	InChI InChI=1S/Al.H3N.2H2O4S/c;;21-5(2,3)4/h;1H3;2(H2,1,2,3,4)/q+3;;;/p-3 Key: LCQXXBOSCBRNNT-UHFFFAOYSA-K ; InChI=1/Al.H3N.2H2O4S/c;;21-5(2,3)4/h;1H3;2(H2,1,2,3,4)/q+3;;;/p-3 Key: LCQXXBOSCBRNNT-DFZHHIFOAY;
	SMILES [Al+3].[O-]S(=O)(=O)[O-].[O-]S([O-])(=O)=O.[NH4+];
Properties
Chemical formula	(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)
Solubility in water	15 g/100 ml (20 °C, dodecahydrate)
Structure
Crystal structure	Hexagonal (anhydrous); Cubic (dodecahydrate)
Coordination geometry	Octahedral (Al3+)
Hazards
	GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H315, H319
Precautionary statements	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). verify (what is ?) Infobox references

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.

Names

Other names Ammonium alum sulfate Tschermigite
Identifiers
CAS Number	7784-25-0^Y 7784-26-1 (dodecahydrate)^Y
3D model (JSmol)	Interactive image
ChemSpider	2297489^Y 56419 (dodecahydrate)^Y
ECHA InfoCard	100.029.141
EC Number	232-055-3 616-522-2 (dodecahydrate)
E number	E523 (acidity regulators, ...)
KEGG	D02842 (dodecahydrate)
PubChem CID	3032540 62668 (dodecahydrate)
RTECS number	WS5640010
UNII	DPU64XYB1D^Y 5C36DRL9ZN (dodecahydrate)^Y
CompTox Dashboard (EPA)	DTXSID7051428
InChI InChI=1S/Al.H3N.2H2O4S/c;;21-5(2,3)4/h;1H3;2(H2,1,2,3,4)/q+3;;;/p-3^Y Key: LCQXXBOSCBRNNT-UHFFFAOYSA-K^Y InChI=1/Al.H3N.2H2O4S/c;;21-5(2,3)4/h;1H3;2(H2,1,2,3,4)/q+3;;;/p-3 Key: LCQXXBOSCBRNNT-DFZHHIFOAY
SMILES [Al+3].[O-]S(=O)(=O)[O-].[O-]S([O-])(=O)=O.[NH4+]
Properties
Chemical formula	(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)
Solubility in water	15 g/100 ml (20 °C, dodecahydrate)
Structure
Crystal structure	Hexagonal (anhydrous) Cubic (dodecahydrate)
Coordination geometry	Octahedral (Al³⁺)
Hazards
GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H315, H319
Precautionary statements	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). Y verify (what is ^YN ?) Infobox references