Sodium Thiosulphate Pentahydrate
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1. Products Information
Definition：Sodium thiosulfate is a sulfur-containing inorganic compound, commonly existing as sodium thiosulfate pentahydrate, also known as sodium hyposulfite or hypo. It appears as colorless and transparent crystals at room temperature, is easily soluble in water, and possesses strong reducibility and coordination ability.
Chemical Formula：The chemical formula of anhydrous sodium thiosulfate is Na2S2O3; the chemical formula of sodium thiosulfate pentahydrate is Na2S2O3·5H2O .
Molecular Weight：The molecular weight of anhydrous sodium thiosulfate is 158.11; the molecular weight of sodium thiosulfate pentahydrate is 248.18.
CAS NO.：The CAS number of anhydrous sodium thiosulfate is 7772-98-7; the CAS number of sodium thiosulfate pentahydrate is 10102-17-7.
Common Specifications：Industrial-grade sodium thiosulfate is commonly available in specifications with a purity of ≥98% and ≥99%. Reagent-grade products include analytical reagent (AR, purity ≥99.0%) and chemically pure (CP, purity ≥98.5%) grades.
SPECIFICATION | STANDARD | RESULTS |
| Na2S2O3·5H2O | ≥98.0% | 99.05% |
| Water Insoluble Matter | ≤0.03% | 0.02% |
| Na2S | ≤0.003% | 0.002% |
| Fe | ≤0.003% | 0.002% |
| Ph | 6.5-9.5 | 7.1 |
SPECIFICATION | STANDARD | RESULTS |
| Na2S2O3·5H2O | ≥99.0% | 99.35% |
| Water Insoluble Matter | ≤0.01% | 0.008% |
| Na2S | ≤0.001% | 0.0009% |
| Fe | ≤0.002% | 0.001% |
| NaCl | ≤0.05% | 0.02% |
| Ph | 6.5-9.1 | 7.2 |
Storage Conditions
It should be sealed and stored in a cool, dry, and well-ventilated warehouse, away from ignition sources and heat, and protected from direct sunlight. It must be stored separately from acids, oxidants, etc., and mixed storage is strictly prohibited. The storage area should be equipped with appropriate materials to contain spills.
2. Physical Properties
Anhydrous sodium thiosulfate is a white crystalline powder, while sodium thiosulfate pentahydrate is a colorless and transparent monoclinic crystal.
It is odorless with a salty taste.
It is readily soluble in water, forming a weakly alkaline aqueous solution, and insoluble in ethanol.
It is prone to efflorescence in dry air. When heated to 100℃, it loses its crystal water and turns into the anhydrous form; upon further heating to 150℃, it decomposes to produce sodium sulfide and sodium sulfate.
3. Main Applications
● In the industrial field
Sodium thiosulfate can be used for post-bleaching dechlorination in the textile industry and pulp bleaching dechlorination in the papermaking industry. It also serves as a complexing agent in the electroplating industry and a cyanide antidote in water treatment.
● In the field of analytical chemistry
It is often used as a standard solution for iodometric titration to determine the content of substances such as iodine and copper ions. In the pharmaceutical field, it can be used for the treatment of cyanide poisoning and also to alleviate symptoms like skin itching and chronic urticaria.
● In addition
It can be used as a fixer in the photography industry to dissolve unexposed silver halides.
4. Packaging Specifications
25kg outer woven bag (with inner lining bag)
25kg kraft paper bag (with inner lining bag)
1000kg ton bag (with inner lining bag)
1250kg large bag (with inner lining bag)
Note: According to customer needs, we also provide other packaging methods, such as ton bags, full plastic bags, kraft paper bags, and drums. Different packaging options correspond to different costs.
5. Core Advantages
● Sodium thiosulfate features strong yet mild reducibility
Causing no harmful substances in applications such as dechlorination and detoxification, thus ensuring high safety.
● It has excellent coordination ability
Capable of forming stable complexes with various metal ions, leading to a wide range of applications.
● With good water solubility
It is easy to prepare solutions of different concentrations, enabling convenient operation.
● It has low industrial production costs and easily accessible raw materials
Offering high cost-effectiveness, and can meet the dual needs of large-scale industrial production and small-dose laboratory use.
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