Molekula
Potassium metabisulfite
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
Potassium metabisulfite is a white crystalline powder used as a preservative and antioxidant in food, wine, and pharmaceuticals. It is also employed in chemical synthesis and water treatment. Available in 1 kg, 5 kg, and 25 kg packaging, it has a CAS number of 16731-55-8, molecular formula K2S2O5, and molecular weight of 222.32 g/mol. Store at ambient temperatures. Signal word: Danger. Molekula supplies Potassium metabisulfite 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.
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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100 g — £26.30 per pack ex VAT · £31.56 inc. VAT
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500 g — £45.00 per pack ex VAT · £54.00 inc. VAT
Need a different quantity or pack?
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 | White powder |
| pH | 3.8 - 4.8 |
| Assay | ≥97.2% |
| Sodium (Na) | ≤2% |
| Thiosulphate (S2O3) | ≤0.1% |
| Chlorine (Cl) | ≤0.5% |
| Sulphur dioxide (SO2) | ≥56% |
Storage & handling
| Property | Value |
|---|---|
| Storage Temperature | Ambient |
| Acidity | Neutral |
Literature values
Published physical properties of the substance, not batch specifications.
| Property | Value |
|---|---|
| Appearance | White powder |
| Odour | Sulfur dioxide odor |
| Density | 2.34 (relative, water = 1) |
| Solubility (other solvents) | Freely soluble in water; insoluble in alcohol |
Source: PubChem CID 28019 (HSDB, ICSC)
Identification
| Property | Value |
|---|---|
| SKU | 55202280 |
| CAS Number | 16731-55-8 |
| EC Number | 240-795-3 |
| Molecular Formula | K2S2O5 |
| Molecular Weight | 222.32 |
| Exact Mass | 221.8461 |
| SMILES | [O-]S(=O)S(=O)(=O)[O-].[K+].[K+] |
| InChIKey | RWPGFSMJFRPDDP-UHFFFAOYSA-L |
| InChI | InChI=1S/2K.H2O5S2/c;;1-6(2)7(3,4)5/h;;(H,1,2)(H,3,4,5)/q2*+1;/p-2 |
| PubChem CID | 28019 |
| REACH Code | Y110 |
| TSCA Listed | Yes |
| HTS Code | 2832.20.0000 |
| Tariff Code | 2832200000 |
Safety & GHS
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Corrosive
GHS05
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Health Hazard
GHS07
Hazard statements
- EUH031 Contact with acids liberates toxic gas
- H315 Causes skin irritation
- H318 Causes serious eye damage
- H335 May cause respiratory irritation
Precautionary statements
- P261 Avoid breathing dust/fume/gas/mist/vapours/spray
- P264 Wash thoroughly after handling
- P280 Wear protective gloves/protective clothing/eye protection/face protection
- P302+P352 IF ON SKIN: Wash with soap and water
- P304+P340 IF INHALED: Remove victim to fresh air and keep at rest in a position comfortable for breathing
- P305+P351+P338 IF IN EYES: Rinse continuously with water for several minutes. Remove contact lenses if present and easy to do, continue rinsing
Documents
Safety Data Sheets (SDS)
Available in English, German, Spanish, French, Italian, Portuguese, Arabic, Dutch.
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
- Dipotassium disulfite
- Dipotassium metabisulfite
- Dipotassium pyrosulfite
- Ins-224
- Potassium disulfite
- Potassium disulfite (K2S2O5)
- potassium metabisulphite
- Potassium pentaoxodisulfate
- Pyrosulfurous acid, dipotassium salt
- Sobisu
Frequently asked questions
What is potassium metabisulfite used for?
It is commonly used as a preservative in food and beverages, and as a reducing agent in chemical synthesis.
What is the chemical formula and molecular weight of potassium metabisulfite?
The formula is K2S2O5 and the molecular weight is 222.32 g/mol.
How should potassium metabisulfite be stored?
It should be stored at ambient temperature, in a dry and well-ventilated area.
What grade of potassium metabisulfite does Molekula supply?
Molekula supplies reagent grade potassium metabisulfite.
Can Molekula supply potassium metabisulfite in bulk?
Yes, Molekula can supply potassium metabisulfite in bulk quantities upon request.
What documentation comes with a purchase of potassium metabisulfite?
Each order includes a Certificate of Analysis and Safety Data Sheet (SDS).
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.