Aluminum sulfate | |
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Names: | aluminum sulfate cake alum filter alum papermaker's alum Е520 food additive
|
Formula: | Al2(SO4)3 (anhydrous) Al2(SO4)3 · 18H2O (octadecahydrate) |
SMILES: | [O-]S(=O)(=O)[O-].[O-]S(=O)(=O)[O-].[O-]S(=O)(=O)[O-].[Al+3].[Al+3] |
Molar mass: | 342.147 g/mol (anhydrous) 666.415 g/mol (octadecahydrate) |
Density: | 2.710 g/cm3 (anhydrous) 1.69 g/cm3 (octadecahydrate) |
Crystal system: | monoclinic (octadecahydrate) α=90°, γ=90° hexagonal (anhydrous) a=8.032 Å, b=8.032 Å, c=21.36 Åα=90°, β=90°, γ=120° monoclinic (pentahydrate) a=5.4843 Å, b=10.7958 Å, c=20.8427 Åα=90°, β=96.44°, γ=90° monoclinic (octahydrate) a=7.37 Å, b=20.008 Å, c=9.624 Åα=90°, β=91.62°, γ=90° monoclinic (decahydrate) a=12.4207 Å, b=7.2896 Å, c=20.239 Åα=90°, β=97.121°, γ=90° triclinic (alunogen) a=7.42 Å, b=26.97 Å, c=6.02 Åα=89.57°, β=97.34°, γ=91.53° monoclinic (aluminite) a=7.44 Å, b=15.583 Å, c=11.7 Åα=90°, β=110.18°, γ=90° monoclinic (jurbanite) a=8.3965 Å, b=12.479 Å, c=8.1549 Åα=90°, β=101.917°, γ=90° monoclinic (felsobanyaite) a=13.026 Å, b=10.015 Å, c=11.115 Åα=90°, β=104.34°, γ=90° |
Shapes: |
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Color: | white colorless |
Melting point: | 86.5 °C359.65 K <br />187.7 °F <br />647.37 °R <br /> (octadecahydrate) |
Decomposition point: | 580 °C853.15 K <br />1,076 °F <br />1,535.67 °R <br /> (anhydrous) 150 °C423.15 K <br />302 °F <br />761.67 °R <br /> (octadecahydrate) 160 °C433.15 K <br />320 °F <br />779.67 °R <br /> (tetradecahydrate) 250 °C523.15 K <br />482 °F <br />941.67 °R <br /> (decahydrate) 420 °C693.15 K <br />788 °F <br />1,247.67 °R <br /> (trihydrate) |
Refractive index: | 1.47 (octadecahydrate) |
Magnetic properties: | diamagnetic χ=-9.30 · 10-5cm³/mol |
Hardness: | fragile (1.5 on Moh's scale) |
Toxicity: | slightly toxic LD50=980mg/kg |
Description
Inorganic compound, salt of transitional metal aluminum and inorganic sulfuric acid From water solutions crystallizes as octadecahydrate.
Minerals
Occurs in nature as alunogen, aluminite, rostite, jurbanite and felsobanyaite minerals.
Precursors
Reaction between aluminum hydroxide and sulfuric acid
Chemical equation:
100.00
g of aluminum sulfate octadecahydrate
а 23.41
g of aluminum hydroxide and 119.33
g of 37%
sulfuric acid is required.Add acid to the flask, then add small parts of aluminum compound with stirring until it will totally dissolve . After reaction will stop, filter the solution and use it for crystal growing.
Reaction between potassium alum, sodium hydroxide and sulfuric acid
Chemical equation:
100.00
g of aluminum sulfate octadecahydrate
а 77.49
g of aluminum-potassium sulfate and 36.01
g of sodium hydroxide or 119.33
g of 37%
sulfuric acid is required.Add to the flask with alums solution small parts of sodium hydroxide solution and stir. The large amount of poorly soluble precipitate will form. Settle it out and wash it from soluble impurities few times.Add acid to the flask, then add small parts of aluminum compound with stirring until it will totally dissolve . After reaction will stop, filter the solution and use it for crystal growing.
Reaction between metal aluminum and sulfuric acid
Chemical equation:
100.00
g of aluminum sulfate octadecahydrate
а 8.10
g of чистый aluminum and 119.33
g of 37%
sulfuric acid is required.Add diluted acid solution to the flask, then add aluminum pieces, shavings or powder and stir it until gas emission will stop. After reaction will stop, filter the solution and use it for crystal growing.
Influence of pH level
Addition of sulfuric acid prevents compounds hydrolysis.
Storage conditions
Store in its original form or under several layers of varnish at average humidity and room temperature. Do not store in matchboxes or cotton wool and do not heat.
Solubility
Temperature | гр/100,00 гр water | гр/100,00 гр ethylene glycol | |
---|---|---|---|
(anhydrous) | (octadecahydrate) | (anhydrous) | |
0°C273.15 K <br />32 °F <br />491.67 °R <br /> | 31.2 | 86.85 | |
10°C283.15 K <br />50 °F <br />509.67 °R <br /> | 33.5 | 95.8 | |
15°C288.15 K <br />59 °F <br />518.67 °R <br /> | ~35.0 | ~102 | |
20°C293.15 K <br />68 °F <br />527.67 °R <br /> | 36.4 | 107.35 | 16.8 |
25°C298.15 K <br />77 °F <br />536.67 °R <br /> | 38.5 | ~117 | |
30°C303.15 K <br />86 °F <br />545.67 °R <br /> | 40.4 | 127.6 | |
40°C313.15 K <br />104 °F <br />563.67 °R <br /> | 45.8 | 167.6 | |
50°C323.15 K <br />122 °F <br />581.67 °R <br /> | 52.2 | 201.4 | |
60°C333.15 K <br />140 °F <br />599.67 °R <br /> | 59.2 | 262.6 | |
70°C343.15 K <br />158 °F <br />617.67 °R <br /> | ~66.1 | 348.2 | |
80°C353.15 K <br />176 °F <br />635.67 °R <br /> | 73 | ~600 | |
90°C363.15 K <br />194 °F <br />653.67 °R <br /> | 80.8 | ~852 | |
100°C373.15 K <br />212 °F <br />671.67 °R <br /> | 89.04 | 1104 |
Gallery
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Saturated solution crystallization while temperature decreases below 50 °CAluminum sulfate, Yaroslav Zavada, VKontakteVKontakte
Video
Sources
- R.A.Kiper Properties of compounds. Handbook
- R.A.Kiper Properties of compounds. Handbook
- Chemicalbook.com site
- Chemport.ru handbook
- E.Kato, Crystal structure of anhydrous aluminum sulfate
- T.Fischer, Crystal structure of dialuminium tris(sulfate) pentahydrate
- T.Fischer, Crystal structure of dialuminium tris(sulfate) octahydrate
- T.Fischer, Crystal structure of dialuminium tris(sulfate) decahydrate
- S.Sabelli, The crystal structure of aluminite
- S.Sabelli, Refinement of the crystal structure of jurbanitejurbanite
- L.Farkas, Crystal structure determinations of felsobanyaite and basaluminite
- J.Kaduk, Use of the Inorganic Crystal Structure Database as a problem solving tool
Aluminum compounds | |
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Simple |
Aluminum sulfate (Al2(SO4)3) • Aluminum-ammonium sulfate (NH4Al(SO4)2) • Aluminum-potassium sulfate (KAl(SO4)2) |
Complex |