Potassium sulfite
Chemical compound From Wikipedia, the free encyclopedia
Potassium sulfite is the inorganic compound with the formula K2SO3. It is the salt of potassium cation and sulfite anion. It is a white solid that is highly soluble in water. Potassium sulfite is used for preserving food and beverages.[2]
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| Names | |
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| IUPAC name
Potassium sulfite | |
Other names
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| Identifiers | |
3D model (JSmol) |
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| ChemSpider | |
| ECHA InfoCard | 100.030.279 |
PubChem CID |
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| UNII | |
CompTox Dashboard (EPA) |
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| Properties | |
| K2SO3 | |
| Molar mass | 158.26 g/mol |
| Appearance | White solid |
| Density | 2.49 g/cm3[1] |
| Soluble | |
| Acidity (pKa) | 8 |
| −64.0·10−6 cm3/mol | |
| Hazards | |
| Flash point | Non-flammable |
| Related compounds | |
Other anions |
Potassium sulfate Potassium selenite |
Other cations |
Sodium sulfite |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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History
Potassium sulfite was first obtained by Georg Ernst Stahl in the early 18th century,[3] and was therefore known afterwards as Stahl's sulphureous salt. It became the first discovered sulfite and was first properly studied along with other sulfites by French chemists in the 1790s, and it was called sulphite of potash in the early 19th century.[4] Gilles-François Boulduc also discovered the salt in water of Passy in the 1720s.[5]
Production and reactions
Potassium sulfite is produced by the thermal decomposition of potassium metabisulfite at 190 °C:[6]
- K2S2O5 → K2SO3 + SO2
Structure
The structure of solid K2SO3, as assessed by X-ray crystallography. The S-O distances are 1.515 Å, and the O-S-O angles are 105.2°[1]
References
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