Potassium disulfate
Structural formula | |||||||||||||||||||
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General | |||||||||||||||||||
Surname | Potassium disulfate | ||||||||||||||||||
other names |
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Molecular formula | K 2 S 2 O 7 | ||||||||||||||||||
Brief description |
white, odorless solid |
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External identifiers / databases | |||||||||||||||||||
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properties | |||||||||||||||||||
Molar mass | 254.32 g mol −1 | ||||||||||||||||||
Physical state |
firmly |
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density |
2.28 g cm −3 |
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Melting point |
419 ° C |
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solubility |
soluble in water; reacts with decomposition |
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safety instructions | |||||||||||||||||||
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As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . |
Potassium disulfate or potassium pyrosulfate K 2 S 2 O 7 is the potassium salt of disulfuric acid .
Properties and appearance
Dipotassium disulfate is a hygroscopic, moisture-sensitive, white and odorless solid that is soluble in water, whereby its aqueous solution reacts strongly acidic.
The result of heating potassium hydrogen sulfate :
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With further heating, the potassium disulfate breaks down at approx. 600 ° C into potassium sulfate and sulfur trioxide :
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Upon contact with water, potassium disulfate decomposes into sulfuric acid and potassium sulfate:
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use
Potassium disulfate is used, for example, for the acidic digestion of salts in the heat:
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The iron (III) sulfate formed is water-soluble.
Individual evidence
- ↑ a b c d e f Entry on potassium disulphate in the GESTIS substance database of the IFA , accessed on February 1, 2016(JavaScript required) .
- ↑ SB Rasmussen, KM Eriksen, G. Hatem, F. da Silva, K. Ståhl, R. Fehrmann: Conductivity, Thermal Measurements, X-ray Investigations, and Phase Diagram of the Na 2 S 2 O 7 -K 2 S 2 O 7 system. In: The Journal of Physical Chemistry B. 105, 2001, pp. 2747-2752, doi : 10.1021 / jp0039262 .
- ^ ASTM International: A Manual for the Chemical Analysis of Metals. ASTM International, p. 86 ( limited preview in Google Book search).