Industrial chemicals · Taylor, TXTechnical Data Sheet
Sodium Metabisulfite - ACS Grade
ACS Grade
- CAS number
- 7681-57-4
- Structure
Structure · PubChem - Grade
- ACS Grade
- Signal word
- Danger
- Hazards
Identity & Composition
- Product Name
- Sodium Metabisulfite - ACS Grade
- Alliance Code
- sodium-metabisulfite-acs-grade
- Grade
- ACS Grade
- Concentration
- —
- CAS Number
- 7681-57-4PubChem
- Formula
- —PubChem
- Molecular Weight
- —PubChem
- Product Type
- Pure substance
Specifications
| Test | Specification | Typical | Method | Source |
|---|---|---|---|---|
| Assay (Na2S2O5) | Min. 97.0% | 98.8% | — | Interpreted |
| Chloride (Cl) | Max. 0.05 % | 0.0039 % | — | Interpreted |
| Heavy metals (as Pb) | Max. 0.001 % | 0.00008 % | — | Interpreted |
| Identification | Pass Test | Passes test | — | Interpreted |
| Insoluble matter | Max. 0.005 % | 0.00088 % | — | Interpreted |
| Iron (Fe) | Max. 0.002 % | 0.00020 % | — | Interpreted |
| Thiosulfate (S2O3) | Max. 0.05 % | 0.0085 % | — | Interpreted |
| Sulfur dioxide (SO2), available | Min. 65.0% | 66.5% | Iodometric titration (I2 / Na2S2O3 back-titration) | Interpreted |
Values are reproduced from the current product reference. Source labels do not by themselves establish a supplier guarantee or a test result for your lot. Confirm applicable acceptance limits and request lot-specific documentation.
Available GradesSame CAS, alternate grades and concentrations
| Grade | Concentration | Typical Assay | SKU | TDS |
|---|---|---|---|---|
| This grade ACS Grade | — | — | current | current |
| Food Grade | — | — | sodium-metabisulfite-food-grade | View TDS → |
| Technical Grade | — | — | sodium-metabisulfite-technical-grade | View TDS → |
Typical assay shown is the rolling-window mean from the sibling product's most recent lots. Grade selection drives downstream end-use — verify the sibling grade matches your specification before substitution.
Physical & Chemical Properties
| Property | Value | Source |
|---|---|---|
| Appearance | White to yellowish | Interpreted |
| Odor | In the presences of traces of water, it develops an odor of sulfur dioxide | Published reference |
| pH | 4 to 6 | Interpreted |
| Density | 1.4 (NIOSH, 2024) - Denser than water; will sink | Published reference |
| Boiling Point | Decomposes (NIOSH, 2024) | Published reference |
| Melting Point | greater than 302 °F (Decomposes) (NIOSH, 2024) | Adjudicated |
| Solubility (water) | Clear, colorless to faintly yellow solution | Interpreted |
Materials of Construction
| Material | Rating | Conditions | Source |
|---|---|---|---|
| glass (glass bottle packaging) | Compatible | dry solid ACS-grade powder as supplied; source states packaging only, no concentration or temperature | fishersci.com |
Compatibility is drawn from published manufacturer and supplier documentation for this product; each rating is sourced. Confirm against your specific duty cycle before equipment selection.
Regulatory & Transport
DOT / 49 CFR
- UN Number
- Not regulatedAdjudicated
- Hazard Class
- Not regulatedAdjudicated
- Packing Group
- Not regulatedAdjudicated
- Proper Shipping Name
- Not regulatedAdjudicated
GHS / OSHA HCS 2024
- Signal Word
- DangerAdjudicated
- H-Codes (Hazard Statements)
- H302, H318Adjudicated
- P-Codes (Precautionary Statements)
- P264, P270, P280, P301+P312, P305+P351+P338, P310, P313, P330, P501Adjudicated
Occupational Exposure Limits
- OSHA PEL (29 CFR 1910.1000)
- —no canonical
- ACGIH TLV
- —no canonical
- NIOSH REL
- 5 mg/m³ TWANIOSH Pocket Guide
- NIOSH IDLH
- —no canonical
Transport descriptions reflect 49 CFR 172.101 lookup at time of publication. Sourced data: NIOSH Pocket Guide for REL/IDLH, OSHA Z-Tables for PEL. Always verify against the latest regulatory text before shipment-critical decisions.
Supplier Qualification Packet
One zipped download containing the TDS, SDS, latest lot COA (when available), and a fresh Letter of Continuing Guaranty for Sodium Metabisulfite - ACS Grade. Every file included is SHA-256 hashed and listed in a manifest your QA team can audit.
Applications
- Used as an antioxidant, disinfectant or preservative agent (ACS/reagent grade material)labdepotinc.com
- High-purity laboratory applications, where ACS-grade specifications are the reference standardlabdepotinc.com
- Oxygen scavenging in steam boiler water treatment and removal of excess chlorine from wastewateressecousa.com
- Reducing and sulfonating agent in chemical processing, including surfactants and polymerizationessecousa.com
Applications are drawn from published manufacturer and supplier documentation; each is sourced. Suitability for a specific use is the buyer's to confirm.
Storage & Handling
- Recommended Storage
- Keep containers tightly closed in a cool, dry, well-ventilated place away from heat, moisture, water, acids and oxidizing agents; it releases sulfur dioxide slowly in humid air. The product consumes oxygen, so oxygen deficiency can develop in closed containers and tanks.Adjudicated
- Handling Precautions
- Use standard chemical PPE — splash goggles, gloves, lab coat. Refer to SDS for hazard-specific PPE requirements.Class-level guidance — not product-specific; the SDS controls.
- Incompatibilities
- Acids (release toxic sulfur dioxide gas); water and ice; strong oxidizing agents; nitrites and nitrates; chlorates; alkalis and strong bases; heavy-metal compounds.Adjudicated
- Shelf Life
- Consult Technical Services for product-specific shelf life
For full hazard, PPE, and emergency response guidance, refer to the Safety Data Sheet (SDS) for this product. The SDS controls in all cases where guidance differs.
Packaging & Logistics
Shipping Description (US DOT)
Not regulated for transport.
Confirm against shipping documents and carrier requirements before tender.
Freight classification is a fallback estimate. Verify with carrier before tender.
Revision History
Last reviewed 2026-07-17 by Andre Taki, Chief Commercial Officer, DOT Hazmat–certified (49 CFR 172.704).
| Version | Date | Change | Trigger |
|---|---|---|---|
| 1.5 | 2026-10-13 | Canonical data updated: 4 fields changed via the provenance/adjudication pipeline.
| canonical_change |
| 1.4 | 2026-10-07 | Canonical data updated: 3 fields changed via the provenance/adjudication pipeline.
| canonical_change |
| 1.3 | 2026-10-05 | Canonical data updated: 1 field changed via the provenance/adjudication pipeline.
| canonical_change |
| 1.2 | 2026-09-30 | Canonical data updated: 1 field changed via the provenance/adjudication pipeline.
| canonical_change |
| 1.1 | 2026-07-17 | Canonical data re-verified: 7 fields updated against independent vendor SDSs, CLP Annex VI, 49 CFR, and OSHA HazCom 2024 (GHS classification, hazard/precautionary codes, signal word, physical properties as applicable).
| canonical_change |
| 1.0 | 2026-05-20 | Initial URL-first TDS published from canonical chemistry registry. | initial |
This Technical Data Sheet is provided for technical reference. The Safety Data Sheet (SDS) controls in all cases where guidance differs. Values reflect Alliance Chemical canonical data at time of generation; subsequent revisions are recorded in the Revision History above.