Sodium aluminium sulfate
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| Sodium aluminium sulfate | |
|---|---|
| IUPAC name | Aluminium sodium bis(sulfate) — water (1:12) |
| Other names | Sodium alum Soda alum E521 |
| Identifiers | |
| InChI | InChI=1/Al.Na.2H2O4S.12H2O/c;;2*1-5(2,3)4;;;;;;;;;;;;/h;;2*(H2,1,2,3,4);12*1H2/q+3;+1;;;;;;;;;;;;;;/p-4 |
| InChIKey | ZEMWIYASLJTEHQ-XBHQNQODAL |
| Standard InChI | InChI=1S/Al.Na.2H2O4S.12H2O/c;;2*1-5(2,3)4;;;;;;;;;;;;/h;;2*(H2,1,2,3,4);12*1H2/q+3;+1;;;;;;;;;;;;;;/p-4 |
| Standard InChIKey | ZEMWIYASLJTEHQ-UHFFFAOYSA-J |
| CAS number | [], 7784-28-3 (dodecahydrate) |
| EC number | |
| ChemSpider | |
| Properties[1] | |
| Chemical formula | NaAl(SO4)2·12H2O |
| Molar mass | 458.28 g/mol |
| Appearance | while crystalline powder |
| Density | 1.6754 (20 °C) |
| Melting point |
61 °C |
| Solubility in water | 208 g/100 ml (15 °C) |
| Refractive index (nD) | 1.4388 |
| Structure[2] | |
| Crystal structure | Cubic, cP96 |
| Space group | Pa3, No. 205 |
| Lattice constant | a = 1221.4 pm |
| Coordination geometry | Octahedral (Na+) Octahedral (Al3+) |
| Hazards | |
| EU index number | not listed |
| Flash point | non-flammable |
| Related compounds | |
| Other cations | Ammonium aluminium sulfate Potassium aluminium sulfate |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) | |
Sodium aluminium sulfate, NaAl(SO4)2·12H2O or Na2SO4·Al2(SO4)3·24H2O, also known as soda alum or sodium alum, is a form of alum used in the acidity regulator of food (E521) as well as in the manufacture of baking powder. It is also a common mordant for the preparation of hematoxylin solutions for staining cell nuclei in histopathology.
The classical cubic alum structure is the dodecahydrate, which is known in mineralogy as alum-(Na).[3][4] Two other rare mineral forms are known: mendozite (undecahydrate)[5] and tamarugite (hexahydrate).[6]
References
- ↑ CRC Handbook of Chemistry and Physics, 62nd ed.; Weast, Robert C., Ed.; CRC Press: Boca Raton, FL, 1981; p B-146. ISBN 0-8493-0462-8.
- ↑ Cromer, D. T.; Kay, A. C.; Larson Refinement of the alum structures. II. X-ray and neutron diffraction of NaAl(SO4)2·12H2O, γ-alum. Acta Crystallogr. 1967, 22 (2), 182–87. DOI: 10.1107/S0365110X67000313.
- ↑ Burke, Ernst A.J. Tidying up mineral names: an IMA-CNMNC scheme for suffixes, hyphens and diacritical marks. Mineralogical Record 2008, 39 (2), 131–35.
- ↑ Template:WebMineral.Template:Mindat.
- ↑ Template:WebMineral.Template:Mindat.
- ↑ Template:WebMineral.Template:Mindat.
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