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Cobalt(II)-ammonium sulfate | |
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Names: | cobalt ammonium sulfate cobalt Tutton's salt ammonium cobalt schoenite ammonium cobaltous sulfate ACoSH ACSH |
Formula: | (NH4)2Co(SO4)2 (anhydrous) (NH4)2Co(SO4)2 · 6H2O (hexahydrate) |
Molar mass: | 287.133 g/mol (anhydrous) 395.222 g/mol (hexahydrate) |
Density: | 1.897 g/cm3 (anhydrous) |
Crystal system: | monoclinic (hexahydrate) a=6.2424 Å, b=12.5231 Å, c=9.2565 Åα=90°, β=107.029°, γ=90° |
Shapes: |
|
Color: | dark red |
Decomposition point: | 70 °C343.15 K <br />158 °F <br />617.67 °R <br /> (hexahydrate) |
Stability: | stable (hexahydrate) hygroscopic (anhydrous) |
Hardness: | relatively strong |
Toxicity: | moderately toxic |
Description
Inorganic compound, double salt of transitional metal cobalt, ammonium ion and inorganic sulfuric acid. From water solutions crystallizes as hexahydrate.
Precursors
Reaction between cobalt(II) and ammonium sulfates
Chemical equation:
100.00
g of cobalt(II)-ammonium sulfate hexahydrate
а 66.57
g of cobalt(II) sulfate hexahydrate
and 33.43
g of ammonium 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 or acetone, then filter the solution and use it for crystal growing.
Due to the high solubility of the product, less amount of water is recommended.
Influence of impurities
Excess of one of sulfates leads to changing a shape of the final crystal. Excess of potassium sulfate makes crystals cloudy/opaque. Small addition of zinc-potassium sulfate or magnesium-potassium sulfate changes crystal color to a lighter one. Compound could be mixed with Tutton's salts in any proportion, producing crystals with different colors and sometimes shapes. It is also possible to cover crystals with a layer of other Tutton's salt, e.g. by placing the crystal into s saturated solution of other salt, producing a crystal-in-crystal.
Influence of pH level
Addition of surfactants has a positive influence on crystal shape and transparency. For example, addition of soap containing sodium lauryl sulfate makes crystal transparent and sharp-edged. Same effect can be achieved by addition of baking soda (~1g of per 100g of solution) - a precipitate containing impurities is formed (e.g. iron salts), solution should be left intact for a while, and then filtered.
Storage conditions
Keep in its original form or under several layers of varnish at average humidity and room temperature. Do not keep crystals near heaters.
Solubility
Temperature | g/100,00 g water | |
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(anhydrous) | (hexahydrate) | |
0°C273.15 K <br />32 °F <br />491.67 °R <br /> | ~6 | 8.92 |
10°C283.15 K <br />50 °F <br />509.67 °R <br /> | ~9.2 | 13.98 |
20°C293.15 K <br />68 °F <br />527.67 °R <br /> | ~12.6 | 19.54 |
25°C298.15 K <br />77 °F <br />536.67 °R <br /> | ~14.7 | 22.53 |
30°C303.15 K <br />86 °F <br />545.67 °R <br /> | ~17 | 25.67 |
40°C313.15 K <br />104 °F <br />563.67 °R <br /> | ~21.9 | 32.46 |
50°C323.15 K <br />122 °F <br />581.67 °R <br /> | ~27 | 40.03 |
60°C333.15 K <br />140 °F <br />599.67 °R <br /> | ~33.5 | 48.51 |
70°C343.15 K <br />158 °F <br />617.67 °R <br /> | ~40 | 58.09 |
Gallery
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Grown within 2 monthsCobalt(II)-ammonium sulfate, Egor Kazakov, VKontakteVKontakte
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Grown within 2 monthsCobalt(II)-ammonium sulfate, Egor Kazakov, VKontakteVKontakte
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Mix of magnesium-ammonium and cobalt(II)-ammonium sulfates with ration 5:1Magnesium-ammonium sulfate, Manzana cristal, twitterTwitter
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Addition of ~5-10% cobalt(II)-ammonium sulfate and magnesium-ammonium chromateMagnesium-ammonium sulfate, Vladimir Semikin, VKontakteVKontakte
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Cobalt(II)-ammonium sulfate crystal coated with a layer of zinc-ammonium sulfate (incomplete coating)Cobalt(II)-ammonium sulfate, Rostislav Dolgikh, VKontakteVKontakte
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Cobalt(II)-ammonium sulfate crystal coated with a layer of zinc-ammonium sulfate (complete coating)Cobalt(II)-ammonium sulfate, Rostislav Dolgikh, VKontakteVKontakte
Video
Sources
Cobalt compounds | |
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Salts |
Cobalt(II) chloride (CoCl2) • Cobalt(II) nitrate (Co(NO3)2) • Cobalt(II) oxalate (CoC2O4) • Cobalt(II) sulfate (CoSO4) • Cobalt(II) tartrate (CoC4H4O6) |
Double salts |
Cerium(III)-cobalt nitrate (3Co(NO3)2 · 2Ce(NO3)3) • Cerium(III)-cobalt-manganese nitrate (3(Co,Mn)(NO3)2 · 2Ce(NO3)3) • Cobalt(II)-ammonium sulfate ((NH4)2Co(SO4)2) • Cobalt(III)-ammonium sulfate (NH4Co(SO4)2) • Cobalt(II)-potassium sulfate (K2Co(SO4)2) |
Complexes |
Cyanocobalamin (C63H88CoN14O14P) • Hexamminecobalt(III) chloride ([Co(NH3)6]Cl2) • Hexanitrocobaltates • Hexacyanocobaltates • Trioxalatocobaltates |