Molekula
Sodium sulfite anhydrous
Supplying 4,500+ customers in over 80 countries
ISO 9001:2015 & ISO 14001:2015 certified · Supplying laboratories and industry since 2000 · Listed pack sizes are a starting point — we manufacture, source and repack to the quantity you need
Sodium sulfite anhydrous is a white, water-soluble powder primarily used as a reducing agent, antioxidant, and preservative in food, pharmaceuticals, and industrial processes like pulp bleaching and wastewater treatment. It prevents oxidation in dried fruits, wines, and processed foods, while also serving as a dechlorinating agent in water systems. This chemical has a CAS number of 7757-83-7, molecular formula Na₂O₃S, and a molecular weight of 126.04 g/mol. It carries no signal word but is labelled with hazard statement EUH031 (contact with acids liberates toxic gas, in this case sulfur dioxide), so it should be kept away from acids; it can be stored at ambient conditions. Molekula supplies sodium sulfite anhydrous from research to bulk quantities with full documentation and ISO 9001:2015 traceability.
Example image for illustration only. Other packaging and pack sizes are available.
Often bought together
Pricing & pack sizes
These pack sizes aren't a limit. Molekula manufactures, sources and repacks to order — if you need 500 kg and only see 1 kg listed, . We quote from grams to multi-tonne.
Need a different size? Add the nearest pack and change the size in your basket — we price it at the same rate per unit.
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1 kg — £28.00 per pack ex VAT · £33.60 inc. VAT
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Tell us how much you need and when — drums, IBCs, sacks or a one-off bulk lot. We'll manufacture or source it and come back with a price.
Prices exclude VAT/sales tax and shipping.
Specifications
| Property | Value |
|---|---|
| Appearance | Fine white crystals |
| Heavy metals | ≤10mg/kg |
| Assay | ≥98.0% |
| Bulk density | 1.5 - 1.7kg/dm3 |
| Iron (Fe) | ≤5mg/kg |
| Lead (Pb) | ≤2mg/kg |
| Arsenic (As) | ≤1mg/kg |
| Selenium (Se) | ≤1mg/kg |
Storage & handling
| Property | Value |
|---|---|
| Storage Temperature | Ambient |
| Acidity | Base |
Literature values
Published physical properties of the substance, not batch specifications.
| Property | Value |
|---|---|
| Appearance | White hexagonal crystals |
| Odour | Odorless |
| Melting Point | 911 °C |
| Density | 2.63 g/cm³ |
| Solubility (other solvents) | Soluble in glycerol; very slightly soluble in alcohol |
| Refractive Index | 1.565 |
Source: PubChem CID 24437 (HSDB)
Identification
| Property | Value |
|---|---|
| SKU | 31377880 |
| CAS Number | 7757-83-7 |
| IUPAC Name | disodium;sulfite |
| EC Number | 231-821-4 |
| Molecular Formula | Na2O3S |
| Molecular Weight | 126.04 |
| Exact Mass | 125.9364 |
| SMILES | [O-]S(=O)[O-].[Na+].[Na+] |
| InChIKey | GEHJYWRUCIMESM-UHFFFAOYSA-L |
| InChI | InChI=1S/2Na.H2O3S/c;;1-4(2)3/h;;(H2,1,2,3)/q2*+1;/p-2 |
| PubChem CID | 24437 |
| REACH Code | Y113 |
| TSCA Listed | Yes |
| HTS Code | 28321000 |
| Tariff Code | 2832100000 |
Safety & GHS
Hazard statements
- EUH031 Contact with acids liberates toxic gas
Precautionary statements
- P231+232 Handle under inert gas. Protect from moisture
- P264 Wash thoroughly after handling
- P280 Wear protective gloves/protective clothing/eye protection/face protection
- P308+313 IF exposed or concerned: Get medical advice/attention
Documents
Safety Data Sheets (SDS)
Available in English, French, German, Italian, Spanish.
Certificate of Analysis (CoA) by batch
Enter a lot or batch number to retrieve the CoA for that specific batch. We can generate one from spec data if no PDF is on file.
Synonyms
- Disodium sulfite
- Natrii sulphis
- Natrium sulfurosum
- Natriumsulfid
- Natriumsulfit
- S-WAT
- SODIUM SULFITE
- Sodium sulphite
- Sulftech
- Sulfurous acid, disodium salt
Frequently asked questions
What is sodium sulfite anhydrous commonly used for?
Sodium sulfite anhydrous is primarily used as a reducing agent in photography, pulp and paper processing, and as a preservative in food and water treatment to prevent oxidation.
What is the chemical formula and molecular weight of sodium sulfite anhydrous?
The chemical formula is Na₂SO₃, and the molecular weight is 126.04 g/mol.
How should sodium sulfite anhydrous be stored?
Store in a cool, dry, well-ventilated area at ambient temperature, away from strong oxidizing agents and moisture.
What grades of sodium sulfite anhydrous does Molekula supply?
Molekula supplies sodium sulfite anhydrous in technical/industrial grade for bulk applications.
Can Molekula supply sodium sulfite anhydrous in bulk quantities?
Yes, Molekula can supply sodium sulfite anhydrous in bulk, with quantities tailored to your specific requirements.
What documentation is provided with an order of sodium sulfite anhydrous?
Each order includes a Certificate of Analysis (CoA), Material Safety Data Sheet (MSDS), and a packing list for traceability.
Ready to order or need a custom pack?
Tell us the product, grade, and quantity — Molekula usually responds within one working day with pricing and lead time.