Sodium sulfite
CAS 7757-83-7Na2O3S126.05 g/mol
Sodium sulfite is an inorganic sodium salt having sulfite as the counterion. It has a role as a reducing agent and a food preservative. It is an inorganic sodium salt and a sulfite salt. It contains a sulfite.
IUPAC: disodium;sulfite
PubChem
Physical & Chemical Properties
| Melting Point | Decomposes (NTP, 1992) |
| Boiling Point | Decomposes (NTP, 1992) |
| Density | 2.633 at 59 °F (USCG, 1999) - Denser than water; will sink |
| Solubility | Soluble in 3.2 parts (NTP, 1992) |
| Vapor Pressure | Negligible (NTP, 1992) |
| pH | 8,5-11,5 (anhydrous: 10 % solution; heptahydrate: 20 % solution) |
| Appearance | Sodium sulfite is a white odorless powder. Density 2.633 g / cm3. Moderately toxic. Sinks in water and dissolves slowly. Also transported as a heptahydrate Na2SO3.7H2O. |
Data: PubChem · Last updated: 4/20/2026
GHS Classification
No GHS classification data available.
Classification data is sourced from ECHA.
Regulatory Compliance
TSCA
Listed
note: Status based on EPA TSCA Active Inventory · inventory name: TSCA Chemical Substance Inventory
View sourceGlobal Trade Intelligence
No trade flow data available for this chemical.
HS Code(s): 2832
Data: UN Comtrade
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