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Sodium sulfite heptahydrate

Sodium sulfite heptahydrate


Colorless crystals

  • Product ID: SO31313
  • Formula: Na2SO3·7H2O
  • MW: 252.15g/mol
  • CAS:  10102-15-5
  • Purity: 98%+
  • MP: water loss around 150℃, decomposes after 500℃
  • Solubility: 220-240 g/L in water
  • Synonyms: Disodium sulfite, heptahydrate; sulfurous acid, sodium salt, heptahydrate 


Sodium sulfite heptahydrate is a soluble, hydrated sodium salt of sulfurous acid (sulfite) with the chemical formula Na2SO3·7H2O. It is also used as a preservative to prevent discoloration of objects. Sodium sulfite exhibits bleaching, desulfurizing, and dechlorinating properties. It is also useful as an oxygen scavenger in photography, tanning, paper & pulp, steam boilers where it plays a key role in remediating corrosion corrosion problems. In synthetic chemistry, sodium sulfite heptahydrate is used as a sulfonation agent, as well as in the production of sodium thiosulfate.