Sodium thiosulfate pentahydrate

CAS 10102-17-7Na2S2O3 · 5H2OChemical Synthesis

Sodium thiosulfate pentahydrate (CAS: 10102-17-7), with the formula Na2S2O3·5H2O and a molecular weight of 248.18 g/mol, is a crystalline inorganic salt. It is commonly used as a reducing agent, particularly in photography for fixing negatives and prints, and in analytical chemistry for iodometric titrations. This compound also finds application in the synthesis of various chemical complexes and in water treatment processes.

Synonyms: HypoSodium hyposulfiteDithionic acid disodium salt pentahydrate

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Sodium thiosulfate pentahydrate (Na2S2O3 · 5H2O) — chemical structure, CAS 10102-17-7; Chemistry, fine chemical supplied by Tech Serve Solutions

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01 /Applications

Chemical Synthesis

Used in the thiosulfate-assisted synthesis of diamine-CuCN complexes, offering a specific route for creating these coordination compounds.

Analytical Chemistry

Primarily employed as a titrant in iodometric titrations to determine the concentration of oxidizing agents. Its reducing properties are key to this application.

Photography

Historically significant as a 'hypo' or fixer in photographic developing processes, it dissolves unexposed silver halides from film and paper.

Water Treatment

Can be utilized for dechlorination of water, reacting with and neutralizing residual chlorine.

02 /Properties

Molecular weight	248.18
Linear formula	Na2S2O3 · 5H2O
Assay	99-101%
Grade	ACS reagent
Solubility	H2O: soluble1 M, clear, colorless
pH	6.0-8.4 (20 °C, 10%)
Loss on drying	32-37% loss on drying, 16 h (vacuum)
Impurities tested	residual solvents, complies≤0.0005% heavy metals (as Pb)
Application	Applied in a widely useful, thiosulfate-assisted, synthesis of a variety of diamine-CuCN complexes.1
Suitability	complies for appearance of solution

03 /Safety & handling

Protective equipment	Eyeshields, Gloves, type N95 (US), type P1 (EN143) respirator filter
Water hazard class (WGK, DE)	1
Cation traces	As: ≤3 mg/kgCa: ≤50 mg/kgFe: ≤10 mg/kg
Anion traces	chloride (Cl-): ≤500 mg/kgsulfate, sulfite (as SO42-): ≤2000 mg/kgsulfide (S2-): in accordance

Hazard information is provided for guidance. Always consult the product Safety Data Sheet (SDS), available on request, before handling.

04 /Identifiers & registry

CAS number

10102-17-7

MDL number

MFCD00149186

PubChem substance

24853004

05 /Quality & supply

Documentation

Every batch ships with a Certificate of Analysis covering assay, identity and purity; the grade is confirmed against your enquiry. Safety Data Sheets and technical data sheets are available on request.

Supply & logistics

Samples for technical evaluation; bulk MOQ by grade and packaging. In-stock material ships in 7–10 working days, worldwide, with full export documentation.

06 /Frequently asked questions

What is Sodium thiosulfate pentahydrate used for?

Sodium thiosulfate pentahydrate (CAS: 10102-17-7) is used in chemical synthesis, analytical chemistry for iodometric titrations, photography as a fixer, and in water treatment for dechlorination.

What are the CAS number and formula for Sodium thiosulfate pentahydrate?

The CAS number for Sodium thiosulfate pentahydrate is 10102-17-7, and its chemical formula is Na2S2O3·5H2O.

What grade and purity does Tech Serve Solutions supply?

Tech Serve Solutions supplies Sodium thiosulfate pentahydrate in ACS reagent grade with an assay of 99-101%. We do not represent this product as USP, BP, or EP grade.

How should Sodium thiosulfate pentahydrate be handled?

Handle with care using appropriate personal protective equipment, including eyeshields, gloves, and a P1/N95 respirator filter, in a well-ventilated area. Avoid dust formation and contact with skin and eyes. It has a WGK rating of 1 (low hazard).