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Sodium Sulfite

Na2SO3
CAS 7757-83-7 · Formula Na2O3S · MW 126.05 g/mol

Inorganic sulfite reducing agent and oxygen scavenger for water treatment and bleaching. HSDB documents its use in photographic developers, textile and paper bleaching as an antichlor, in dye manufacture, and as an oxygen scavenger in boiler-water and oilfield treatment.

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HS Code
2832.10
At a Glance
Material Family
Acids & Salts
Record Type
Pure compound
Primary Role
Preservation
Functional Roles
SODIUM SULFITE
ANTIOXIDANTHAIR WAVING OR STRAIGHTENINGPRESERVATIVEREDUCING
Applications & Use Cases
  • Boiler and oilfield water: Oxygen scavenger in boiler feedwater and oil wells.
  • Bleaching: Antichlor for dechlorinating textiles and paper pulp.
  • Photography: Reducing agent in photographic developers.
  • Dye manufacture: Reducer and solubilizing agent for dyes.
Physical Properties
Melting Point
Decomposes
Boiling Point
Decomposes
Density
2.633 at 15 °C
Solubility
Soluble in 3.2 parts
Vapor Pressure
Negligible
pH
8,5-11,5 (anhydrous: 10 % solution; heptahydrate: 20 % solution)
Safety & Handling
Full SDS available on request

A grade-specific Safety Data Sheet (SDS) — with the complete hazard classification, handling precautions, and transport information — is supplied with every shipment and available on request. Confirm all safety and regulatory details against the SDS for your specific grade.

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HS / Tariff Classification
Harmonized System (HS) Code — 6-digit international heading
2832 . 10
Chapter 28
Inorganic chemicals; compounds of precious metals and rare-earth metals
Heading 28.32
Internationally harmonized (WCO HS)
Subheading 2832.10
6-digit international code — national tariff line adds further digits
Chemical Identity
CAS Number
7757-83-7
Molecular Formula
Na2O3S
Molecular Weight
126.05 g/mol
IUPAC Name
disodium;sulfite
INCI Name
SODIUM SULFITE
PubChem CID
InChI Key
GEHJYWRUCIMESM-UHFFFAOYSA-L
Synonyms & Trade Names
SODIUM SULFITE Disodium sulfite Sodium sulfite anhydrous Sodium sulphite Sulfurous acid, disodium salt Natrium sulfurosum Sulftech Natriumsulfid Natriumsulfit S-WAT Natrii sulphis Anhydrous sodium sulfite Sodium sulfite (Na2SO3) Exsiccated sodium sulfite Natrum sulphurosum Sodium sulphite anhydrous Sulfurous acid, sodium salt (1:2) Sodium sulfite, anhydrous Sodium sulfite, exsiccated
Full Description

Sodium sulfite (CAS 7757-83-7) is an inorganic sulfite and reducing agent. HSDB documents its use in photographic developers, textile and paper bleaching as an antichlor, in dye manufacture, and as an oxygen scavenger in boiler-water and oilfield treatment. It also silvers glass and removes traces of chlorine from bleached textiles and paper.

Frequently Asked Questions

What is sodium sulfite anhydrous used for?

Sodium sulfite (CAS 7757-83-7) is an inorganic sulfite and reducing agent used as an oxygen scavenger in boiler feedwater and oilfield water treatment, as an antichlor for dechlorinating bleached textiles and paper pulp, as a reducing agent in photographic developers, and as a reducer and solubilizer in dye manufacture.

What is the difference between sodium sulfite and sodium bisulfite?

Sodium sulfite is Na2SO3; sodium bisulfite (sodium hydrogen sulfite) is NaHSO3, the more acidic, partially protonated form. Both act as reducing agents and oxygen scavengers, but they differ in solution pH and active SO2 content. We supply this product as the anhydrous technical granular sulfite, CAS 7757-83-7.

Is sodium sulfite soluble in water?

Yes. The anhydrous technical granular grade dissolves readily in water to give a mildly alkaline solution, which is why it is dosed into boiler and oilfield water as an oxygen scavenger. Refer to the SDS for handling data.

What HS code applies to sodium sulfite?

Sodium sulfite is classified under HS heading 2832.10 (Sulfites; thiosulfates: sodium sulfites). Confirm the destination tariff line with your customs broker before shipping.

What is the cost of bulk sodium sulfite anhydrous?

Pricing for the anhydrous technical granular grade depends on order volume and packaging (bags, supersacks, or bulk). Submit a bulk RFQ with your quantity and delivery point and we will return a current quote with Certificate of Analysis and SDS.

Disclaimer. Information on this page — including properties, identifiers, hazard, transport (DOT/UN) and tariff (HS) classifications, and applications — is provided for general reference and is compiled from authoritative public sources (e.g. PubChem/ECHA, 49 CFR 172.101, the Harmonized Tariff Schedule). Values are typical and are not a guaranteed specification; the Certificate of Analysis (CoA) for the lot purchased governs. Products are sold for industrial and professional use only. Nothing here is a medical, health, or efficacy claim or advice. Always consult the current Safety Data Sheet (SDS) before handling, storage, transport or disposal, and confirm regulatory status, classification and suitability for your application and jurisdiction. Hazard, transport and tariff classifications must be verified for your specific shipment. RawSource makes no warranty, express or implied, and assumes no liability for use of this information. Trademarks. Third-party trademarks and brand names are the property of their respective owners; any reference is nominative — used only to identify a comparable product — and does not imply affiliation with, sponsorship by, or endorsement by the trademark owner.