Na2S2O3·5H2O (Sodium Thiosulfate Pentahydrate): Uses, Specs, and Sourcing Tips

If you’re searching for na2s2o3 5h2o, you’re looking at sodium thiosulfate pentahydrate—a widely used industrial and laboratory chemical valued for its reducing properties and reliable performance in water, process, and analytical applications.

In African trade and FMCG-adjacent supply chains (water treatment, textiles, mining support services, laboratories), demand often comes down to one thing: consistent quality delivered on time, supported by correct documentation and fit-for-purpose packaging.

What is Na2S2O3·5H2O?

Na2S2O3·5H2O is the hydrated form of sodium thiosulfate, commonly supplied as clear-to-white crystalline granules. It is widely traded under the name sodium thiosulfate pentahydrate and differs from the anhydrous form in both handling requirements and dosing calculations.

Key identifiers typically used in procurement:

• Chemical name: Sodium thiosulfate pentahydrate

• Chemical formula: Na2S2O3·5H2O

• CAS number: 10102-17-7

• Molecular weight: 248.18 g/mol

Correct identification is critical, particularly for buyers supplying regulated industries or laboratories.

Common applications of sodium thiosulfate pentahydrate

1) Water treatment and dechlorination

One of the most established uses of na2s2o3 5h2o is the neutralization of chlorine in treated water. It is widely applied in municipal water treatment, industrial utilities, aquaculture systems, swimming pools, and process water where residual chlorine can damage equipment or disrupt downstream processes.

Practical insight: Always confirm whether operating procedures are based on the pentahydrate or anhydrous form, as incorrect assumptions can lead to under- or overdosing.

2) Photography and imaging processes

Sodium thiosulfate has long been used as a photographic fixing agent, helping dissolve unreacted silver halides during film and photographic paper processing. While digital imaging dominates today, demand still exists in specialty, educational, and archival applications.

3) Laboratory and analytical use

In laboratories, sodium thiosulfate pentahydrate plays an important role in iodometric titrations. It is used as a reducing agent to quantify oxidizing substances, making it relevant for water testing, chemical quality control, and some food-related analyses.

Consistency in purity and particle size is especially important for analytical accuracy.

4) Textile and process industries

In textile processing and related industries, sodium thiosulfate may be used to neutralize residual bleaching agents or support controlled reduction steps. For manufacturers, inconsistent chemical quality can lead to variability in finished products, making supplier reliability a key consideration.

What to specify when buying Na2S2O3·5H2O

To avoid costly errors, procurement teams should clearly define requirements when sourcing sodium thiosulfate pentahydrate:

• Hydration state: Specify pentahydrate (5H2O) explicitly.

• Grade: Industrial or laboratory grade, depending on application.

• Purity/assay: Confirm acceptable ranges and require a certificate of analysis where necessary.

• Packaging: Commonly supplied in 25 kg bags; moisture-resistant inner liners are recommended.

• Documentation: SDS, COA, and compliant labeling for the destination market.

Clear specifications reduce delays, rejections, and downstream operational issues.

Storage and logistics considerations in African markets

While sodium thiosulfate pentahydrate is relatively stable, proper logistics planning improves shelf life and usability:

• Store in cool, dry conditions to prevent caking.

• Protect against humidity during port handling and inland transport.

• Use standardized palletization and labeling to simplify warehousing and distribution.

These factors are particularly important in regions with long transit times or variable climate conditions.

How Wigmore Trading can help

Wigmore Trading can help businesses source na2s2o3 5h2o with confidence by supporting:

• Accurate specification matching (grade, hydration state, documentation)

• Export-ready packaging suitable for African trade routes

• Coordinated logistics and supply-chain support from origin to destination

If you’re looking to balance cost, quality, and delivery reliability, Wigmore Trading can help.
Contact Wigmore Trading today to streamline your sourcing.