What form is Sodium Thiosulfate CAS 7772-98-7 supplied in?

Commercial sodium thiosulfate is commonly supplied as sodium thiosulfate pentahydrate, Na2S2O3·5H2O. The page uses CAS 7772-98-7, while some databases assign the pentahydrate CAS 10102-17-7, so confirm the physical form and water of crystallization before ordering.

How is sodium thiosulfate different from sodium sulfite?

Sodium thiosulfate contains the thiosulfate ion S2O3(2-), while sodium sulfite contains SO3(2-). The additional sulfur changes its reducing, metal-complexing, and photographic-fixing behavior.

How is Sodium Thiosulfate used for dechlorination?

Sodium thiosulfate reacts with residual free chlorine and chloramines in water, wastewater, and aquaculture systems to form less harmful species. The required dose should be calculated from the measured chlorine residual and checked by testing to avoid overdosing.

What are the main industrial applications of Sodium Thiosulfate?

Sodium thiosulfate is used for dechlorination, as a photographic fixing agent, in textile and paper processing including sulfur dyeing, and as a reducing, neutralizing, or complexing agent. It is also used in iodometric titration and some metal recovery processes.

What specifications should be checked for Sodium Thiosulfate CAS 7772-98-7?

Confirm assay, appearance, water of crystallization, pH, chloride, sulfate, iron, heavy metals, and insoluble matter. Also specify the intended technical, photographic, or water-treatment grade and whether granules or powder are required.

Sodium Thiosulfate CAS 7772-98-7

Sodium Thiosulfate (CAS 7772-98-7), chemically identified as disodium thiosulfate or sodium hyposulfite, is an inorganic salt functioning as a highly effective dechlorinating agent and metal complexing agent in industrial water treatment and precious metal extraction processes. This stable crystalline compound, also technically referred to as thiosulfuric acid disodium salt, serves as a critical reducing agent for neutralizing chlorine levels in aquaculture and textile bleaching. Sodium Metabisulfite is a related reducing salt for specified dechlorination and bleaching operations, while Sodium Thiosulfate also serves as a fixative in photographic processing. We provide bulk supply of this industrial raw material with competitive factory pricing to ensure operational efficiency for processing plants. Our manufacturing standards guarantee chemical stability, making MSDS, TDS, COA available alongside customized specifications to suit diverse application environments.

CAS: 7772-98-7
Synonyms: disodium thiosulfate, sodium hyposulfite, thiosulfuric acid disodium salt, sodium oxide sulfide, hyposulphite of soda
Einecs: 231-867-5
Molecular Formula: Na₂S₂O₃·5H₂O
Grade: Industrial / Technical / Photographic grade
Package: 25 kg woven bag or kraft bag with inner liner, 1,000 kg jumbo bag or as required

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Product Description

Sodium Thiosulfate is an inorganic salt widely used as a dechlorinating agent, photographic fixer, and process chemical in water treatment, mining, and various industrial applications. It offers reliable performance, good solubility in water, and stable quality suitable for bulk industrial and technical use.

📧 Email: info@industrochem.com – Contact us for detailed specifications, COA and latest price.

1 Physicochemical Properties

2 Applications

3 Storage Conditions

4 Safety Precautions

Physicochemical Properties

Item	Specification / Typical Value
Chemical Name	Sodium Thiosulfate Pentahydrate
CAS No.	7772-98-7
Molecular Formula	Na₂S₂O₃·5H₂O
Molecular Weight	Approx. 248.18 g/mol
Appearance	White crystalline granules or powder
Odor	Odorless
Assay (Na₂S₂O₃)	Typically ≥ 99.0% (on dry basis)
Insoluble Matter	Low, suitable for industrial and water treatment use
Solubility	Freely soluble in water
pH (5–10% aq. solution)	Typically 6.5 – 9.5
Bulk Density	Approx. 1.6 – 1.8 g/cm³
Decomposition / Melting Point	Loses crystal water and decomposes around 48–50 °C
Stability	Stable under normal storage and handling
Incompatibility	Strong acids, strong oxidizing agents

(Typical values; can be adjusted according to your required specification.)

Applications

Water Treatment & Dechlorination
- Neutralizes residual chlorine in municipal and industrial water.
- Used in boiler water, cooling water and wastewater treatment systems to protect downstream equipment and processes.
Photographic Industry
- Acts as a classic fixer for photographic films and papers, dissolving unexposed silver halides.
- Used in traditional darkroom processes and some specialized imaging applications.
Mining & Metallurgy
- Participates in cyanide-related processes and detoxification in precious metal extraction.
- Helps reduce toxicity in cyanide-bearing effluents when properly used in engineered systems.
Chemical & Pharmaceutical Processes
- Functions as a reducing agent and analytical reagent in laboratories and process lines.
- Used as an auxiliary chemical in some pharmaceutical and diagnostic applications (according to local regulations).
Textile & Pulp Industries
- Applied as a reducing and dechlorinating agent after bleaching steps.
- Helps protect fibers and improve final product quality by removing residual oxidants.

If you need a tailored grade for specific applications (high-purity, low insoluble, special particle size), please contact us for customized specifications.

Storage Conditions

Store in a cool, dry, well-ventilated warehouse.
Keep containers tightly closed to prevent moisture uptake and caking.
Protect from direct sunlight, rain and high temperature.
Keep away from strong acids and strong oxidizing agents.
Recommended storage temperature: ambient, avoiding extremes.
Under proper storage, typical shelf life is 24 months from production date.

Safety Precautions

Sodium Thiosulfate is generally considered to have low acute toxicity, but good industrial hygiene practices must always be followed.
Avoid creating or inhaling dust; use local exhaust ventilation where dust may be generated.
Wear appropriate personal protective equipment (PPE): safety glasses or goggles, dust mask/respirator, gloves and protective work clothing.
Avoid contact with eyes and prolonged skin contact. In case of contact, rinse with plenty of water.
Do not eat, drink or smoke in the working area; wash hands thoroughly after handling.
In case of large spills, collect the material mechanically and avoid discharge into natural water bodies.
Dispose of material and packaging in accordance with local regulations.

For detailed SDS and handling guidelines, please request documentation via: info@industrochem.com.

FAQ - Technical & Supply Chain

Q:
What form is Sodium Thiosulfate CAS 7772-98-7 supplied in?

A: Commercial sodium thiosulfate is commonly supplied as sodium thiosulfate pentahydrate, Na2S2O3·5H2O. The page uses CAS 7772-98-7, while some databases assign the pentahydrate CAS 10102-17-7, so confirm the physical form and water of crystallization before ordering.
Q:
How is sodium thiosulfate different from sodium sulfite?

A: Sodium thiosulfate contains the thiosulfate ion S2O3(2-), while sodium sulfite contains SO3(2-). The additional sulfur changes its reducing, metal-complexing, and photographic-fixing behavior.
Q:
How is Sodium Thiosulfate used for dechlorination?

A: Sodium thiosulfate reacts with residual free chlorine and chloramines in water, wastewater, and aquaculture systems to form less harmful species. The required dose should be calculated from the measured chlorine residual and checked by testing to avoid overdosing.
Q:
What are the main industrial applications of Sodium Thiosulfate?

A: Sodium thiosulfate is used for dechlorination, as a photographic fixing agent, in textile and paper processing including sulfur dyeing, and as a reducing, neutralizing, or complexing agent. It is also used in iodometric titration and some metal recovery processes.
Q:
What specifications should be checked for Sodium Thiosulfate CAS 7772-98-7?

A: Confirm assay, appearance, water of crystallization, pH, chloride, sulfate, iron, heavy metals, and insoluble matter. Also specify the intended technical, photographic, or water-treatment grade and whether granules or powder are required.

Ordering & Documentation

Key information for document requests, quotations, and supply planning.

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COA, TDS, SDS/MSDS and packing details are available on request.

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Send the CAS number, grade, quantity, packing preference and destination.

Sample & Supply

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Storage & Shipping

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