Sodium Thiosulfate
| Formula: | Na₂S₂O₃·5H₂O |
| CAS Number: | 7772-98-7 |
| EC Number (EINECS): | 231-867-5 |
| HS Code: | 28321000 |
| UN Number: | Not classified as dangerous |
| IUPAC Name: | Sodium Thiosulfate Pentahydrate |
| Also Known As: | Hypo; Sodium Hyposulfite |
| Molecular Weight, g/mol: | 248.18 |
Typical Specifications
| Appearance: | Colorless to white crystalline powder |
| Odor: | Odorless |
| Melting Point, °C: | 48–50 (loses water above 48°C) |
| Boiling Point, °C: | Decomposes |
| Density, g/cm³ (at 20°C): | 1.667 |
| pH (1% solution): | 6.0–8.0 |
| Purity, %: | ≥99 |
| Grades Available: | Technical, FCC / Food Grade |
| Packaging: | 25kg bags, 50kg bags, 500kg jumbo bags |
Applications / Uses
Primary Applications
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Water treatment (dechlorination)
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Photographic fixing agent
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Reducing agent in chemical synthesis
Secondary Applications
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Gold and silver leaching in mining industry
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Laboratory reagent for titrations
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Used in textile dyeing and printing
End Industries Served: Water Treatment, Photography, Mining, Chemicals, Laboratory, Textile
Safety & Handling Information
Hazard Class (GHS): Not classified as hazardous; may cause mild irritation
Hazard Statements (H-Codes):
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H319: Causes serious eye irritation (dust)
Precautionary Statements (P-Codes):
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P280: Wear protective gloves/eye protection
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P261: Avoid breathing dust
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P305 + P351 + P338: IF IN EYES – rinse cautiously with water
Storage Conditions
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Store in a cool, dry, ventilated place
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Keep container tightly closed
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Protect from moisture and contaminants
Transport Information
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ADR/RID: Not classified as dangerous goods
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IMDG: Not classified as dangerous goods
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IATA: Not classified as dangerous goods