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Sodium metabisulfite

CAS Number
7681-57-4
EC Number
231-673-0
Chemical Formula
H2O5S2.2Na
Molecular Weight
190.11 g/mol

Description

Sodium metabisulfite (CAS 7681-57-4 ), also known as sodium pyrosulfite and sold under the abbreviation SMBS, is an inorganic sulfite salt used across food, industrial, and water treatment sectors. It serves as a preservative, antioxidant, and reducing agent. As E223 , it is a regulated food additive recognized in major international markets. Its ability to release sulfur dioxide under controlled conditions underpins its function across multiple industries and specialized chemical processes. In food and beverage production, E223 prevents oxidative browning and microbial spoilage in dried fruits, wines, seafood, and fruit juices. This ensures product longevity and maintains the aesthetic quality of processed goods. Water treatment plants use SMBS to neutralize residual chlorine in municipal and industrial effluent streams before discharge or further processing. This step is critical for environmental safety and protecting downstream equipment. Textile and leather processors apply it as a bleaching and reducing agent in dye stripping and chrome tanning operations. It provides consistent results in heavy industrial manufacturing environments requiring high-purity chemical inputs. In pharmaceutical manufacturing, it functions as an antioxidant stabilizer in injectable formulations and oral solutions. This is essential where oxygen-sensitive active ingredients require protection to maintain their therapeutic efficacy. Sodium metabisulfite is supplied as a white to off-white crystalline powder or fine granules. Standard commercial grades include food-grade ( FCC -compliant), USP / BP pharmaceutical grade, and technical grade for industrial applications. Bulk supply is available in 25 kg bags, with food and pharma grades accompanied by full compliance documentation. Our logistics network ensures reliable delivery for large-scale manufacturing and chemical processing facilities worldwide. Contact us for supply of Sodium metabisulfite Request Quote

Other Names (Synonyms)

sodium pyrosulfite | sodium metabisulphite | disodium pyrosulfite | Sodium disulfite | Natrii disulfis | Campden Tablets | Disodium metabisulfite | Natrium pyrosulfit | SMBS | E223

Key Technical Features

  • High Purity Grade standard
  • Consistent Batch Quality
  • Full Regulatory & REACH Support
  • Global Logistics Network enabled

Physical Properties

Melting Point150 °C (decomp)
Density1.4 g/cm³
AppearanceSodium metabisulfite is a white crystalline powder. Sulfur dioxide odor. It may be considered the anhydride of 2 molecules of sodium disulfite.
ColorWhite to slightly yellow
OdorSulphorous
FormPowder/Solid
Water Solubility540 g/L (20 ºC)
Refractive Index1.474
pH3.5-5 (50g/l, H2O, 20℃)

Safety & Handling

Danger
GHS05· CorrosiveGHS07· IrritantGHS08· Health Hazard

Hazard Statements

H302Harmful if swallowed
H317May cause an allergic skin reaction
H318Causes serious eye damage
H320Causes eye irritation
H334May cause allergy or asthma symptoms or breathing difficulties if inhaled
H335May cause respiratory irritation
H372Causes damage to organs through prolonged or repeated exposure
H402Harmful to aquatic life
H412Harmful to aquatic life with long lasting effects

Precautionary Statements

P233Keep container tightly closed.
P260Do not breathe dust/fume/gas/mist/vapours/spray.
P261Avoid breathing dust/fume/gas/mist/vapours/spray.
P264Wash … thoroughly after handling.
P270Do not eat, drink or smoke when using this product.
P271Use only outdoors or in a well-ventilated area.
P272Contaminated work clothing should not be allowed out of the workplace.
P273Avoid release to the environment.
P280Wear protective gloves/protective clothing/eye protection/face protection.
P284In case of inadequate ventilation wear respiratory protection.
P317Get emergency medical help.
P319Get medical advice/attention if you feel unwell.
P321Specific treatment (see … on this label).
P330Rinse mouth.
P403Store in a well-ventilated place.
P405Store locked up.
P501Dispose of contents/container in accordance with local regulations.
P265Wash … thoroughly after handling.
P317Get emergency medical help.
P352IF ON SKIN: Wash with plenty of water.
P340IF INHALED: Remove person to fresh air and keep comfortable for breathing.
P317Get emergency medical help.
P317If eye irritation persists: Get medical advice/attention. Get emergency medical help.
P316Get emergency medical help immediately.
P364Take off contaminated clothing and wash it before reuse.
P233Store in a well-ventilated place. Keep container tightly closed.
P338IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.
P338IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.

Trade & Regulatory

HS Code28323010
Storage Class13 - Non Combustible Solids
WGK (Germany)1