Aluminum-potassium sulfate
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Aluminum-potassium sulfate | |
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Names: | aluminum(III)-potassium sulfate potassium-aluminum sulfate potassium alum potash alum Е522 food additive
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Formula: | KAl(SO4)2 (anhydrous) KAl(SO4)2 · 12H2O (dodecahydrate) |
SMILES: | [O-]S(=O)(=O)[O-].[O-]S(=O)(=O)[O-].[Al+3].[K+] |
Molar mass: | 258.202 g/mol (anhydrous) 474.381 g/mol (dodecahydrate) |
Density: | 2.75 g/cm3 (anhydrous) 1.725 g/cm3 (dodecahydrate) |
Crystal system: | hexagonal (anhydrous) a=4.7206 Å, b=4.7206 Å, c=7.9835 Åα=90°, β=90°, γ=120° cubic (dodecahydrate) a=12.164 Å, b=12.164 Å, c=12.164 Åα=90°, β=90°, γ=90° |
Shapes: |
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Color: | colorless |
Melting point: | 92.5 °C365.65 K <br />198.5 °F <br />658.17 °R <br /> (dodecahydrate) |
Refractive index: | 1.4564 (dodecahydrate) |
Radiation properties: | slightly radioactive |
Stability: | stable (dodecahydrate) hygroscopic (anhydrous) |
Hardness: | relatively strong (2 on Moh's scale) |
Toxicity: | slightly toxic LD50~2000mg/kg |
Description
Inorganic compound, double salt of transitional metal aluminum, alkaline metal potassium and inorganic sulfuric acid. From water solutions crystallizes as dodecahydrate.
Minerals
Occurs in nature as alum-(K), kalinite, alunite and steklite minerals.
Where to buy
In pharmacy (as "burnt alum" or "crystal deodorant" - dehydrated alum).
Precursors
Reaction between aluminum and potassium sulfates
Chemical equation:
100.00
g of aluminum-potassium sulfate dodecahydrate
а 70.24
g of aluminum sulfate octadecahydrate
and 18.37
g of potassium sulfate is required.Dissolve compounds in hot water apart and then mix solutions into one container with intense stirring. Cooling or evaporation of a solution will cause double salt crystallyzation.
Reaction between pure aluminum, potassium nitrate and sulfuric acid
Chemical equation:
100.00
g of aluminum-potassium sulfate dodecahydrate
а 5.69
g of aluminum, 21.31
g of potassium nitrate and 111.76
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 aluminum nitrate or chloride and potassium sulfate
Chemical equation:
100.00
g of aluminum-potassium sulfate dodecahydrate
а 79.08
g of aluminum nitrate nonahydrate
or 50.89
g of aluminum chloride hexahydrate
and 73.47
g of potassium sulfate is required.Dissolve compounds in hot water apart and then mix solutions into one container with intense stirring. Cooling or evaporation of a solution will cause double salt crystallyzation. Filter precipitate and wash it wish small amount of ethanol, then filter the solution and use it for crystal growing.
Reaction between aluminum sulfate and nitrate or potassium chloride
Chemical equation:
100.00
g of aluminum-potassium sulfate dodecahydrate
а 93.65
g of aluminum sulfate octadecahydrate
and 21.31
g of potassium nitrate or 15.72
g of potassium chloride is required.Dissolve compounds in hot water apart and then mix solutions into one container with intense stirring. Cooling or evaporation of a solution will cause double salt crystallyzation. Filter precipitate and wash it wish small amount of ethanol, then filter the solution and use it for crystal growing.
Reaction between potassium hydroxide or carbonate, aluminum hydroxide and sulfuric acid
Chemical equation:
100.00
g of aluminum-potassium sulfate dodecahydrate
а 11.83
g of potassium hydroxide or 14.57
g of potassium carbonate, 16.44
g of aluminum hydroxide and 111.76
g of 37%
sulfuric acid is required.Add acid to the flask, then add small parts of potassium and aluminum compound with stirring until it will totally dissolve or, if you use carbonate, until carbon dioxide emission will stop. After reaction will stop, filter the solution and use it for crystal growing.
Influence of impurities
Impurities impact on the crystal shapeCategory:Alums, Tomruen, WikimediaWikimedia
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 |
---|---|
0°C273.15 K <br />32 °F <br />491.67 °R <br /> | 3 |
10°C283.15 K <br />50 °F <br />509.67 °R <br /> | 4 |
15°C288.15 K <br />59 °F <br />518.67 °R <br /> | ~4.95 |
20°C293.15 K <br />68 °F <br />527.67 °R <br /> | 5.9 |
25°C298.15 K <br />77 °F <br />536.67 °R <br /> | 7.23 |
30°C303.15 K <br />86 °F <br />545.67 °R <br /> | 8.39 |
40°C313.15 K <br />104 °F <br />563.67 °R <br /> | 11.7 |
50°C323.15 K <br />122 °F <br />581.67 °R <br /> | 17 |
60°C333.15 K <br />140 °F <br />599.67 °R <br /> | 24.75 |
70°C343.15 K <br />158 °F <br />617.67 °R <br /> | 40 |
80°C353.15 K <br />176 °F <br />635.67 °R <br /> | 71 |
90°C363.15 K <br />194 °F <br />653.67 °R <br /> | 109 |
100°C373.15 K <br />212 °F <br />671.67 °R <br /> | 154 |
Gallery
Growth with slow solvent evaporation methodAluminum-potassium sulfate, Dmitry Shintyakov, Personal crystal growing collectionPersonal crystal growing collection
Gradual increase of borax concentration in the solutionAluminum-potassium sulfate, Rostislav Dolgikh, VKontakteVKontakte
Growth with small borax additionAluminum-potassium sulfate, Andrey Zmitrovich
Growth with small borax additionAluminum-potassium sulfate, Maxim Martinov, VKontakteVKontakte
Growth with small borax additionAluminum-potassium sulfate, Anatoly Bobe, VKontakteVKontakte
Growth with food coloring additionAluminum-potassium sulfate
Growth with food coloring additionAluminum-potassium sulfate, Rostislav Ruzmanov, VKontakteVKontakte
Growth with food coloring additionAluminum-potassium sulfate, Rostislav Ruzmanov, VKontakteVKontakte
Video
Sources
- R.A.Kiper Properties of compounds. Handbook
- R.A.Kiper Properties of compounds. Handbook
- S.Nyburg, Structure of the alums, the sulfate group disorder in the &aplha;-alums
- D.West, Structural disorder, octahedral coordination and two-dimensional ferromagnetism in anhydrous alums
- Personal crystal growing collection
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 |