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Sodium Thiosulfate is generally considered a relatively safe and useful compound in controlled concentrations.
Sodium thiosulfate contains two sulfur atoms in different oxidation states, which gives it strong reducing properties that allow it to neutralize oxidizing agents such as chlorine and iodine in chemical systems.
Sodium Thiosulfate redox behavior is the basis for many of its applications in dechlorination and analytical chemistry.
CAS Number: 7772-98-7
Molecular Formula: Na2O3S2
Molecular Weight: 158.11
EINECS Number: 231-867-5
Synonyms: sodium thiosulfate, thiosulfuric acid, disodium salt, DECHLORINATING SOLUTION;'HYPO';BETZ 0235;ANTICHLOR;SODIUM THIOSULFATE;SODIUM THIOSULFATE, 2.00 N;SODIUN THIOSULFATE;SULFITE STANDARD
Sodium Thiosulfate is a commonly used chemical material, as the fixing agent in photography, film and printing plate-making industry, as a reducing agent used in tanning.
Sodium Thiosulfate is used as a bleaching agent for removing residual and a mordant in the paper and textile industries, as antidotes of cyanide poisoning in medicine, as dechlorination agent and fungicides of drinking water and wastewater in water treatment, as a copper corrosion inhibitor of circulating cooling water and a deoxidizer of boiler water systems.
Sodium Thiosulfate is also used for Cyanide wastewater treatment. Soda ash and sulfur are generally used as raw materials in industry, soda ash reacts with sulfur dioxide produced by the combustion of sulfur to produce sodium sulfite, then add sulfur for boiling reactions, and then filter, bleach, concentrate and crystallize, etc, can obtain sodium thiosulfate pentahydrate.
Other production waste containing sodium sulfide, sodium sulfite, sulfur and sodium hydroxide can also be used, after appropriate treatment to get the product.
Sodium Thiosulfate is an inorganic ionic compound with the chemical formula Na₂S₂O₃ that appears as a white crystalline solid and is widely used in medical, industrial, photographic, and laboratory applications because it acts as a reducing agent and sulfur donor in many chemical reactions.
It is highly water-soluble and typically exists as a stable pentahydrate form (Na₂S₂O₃·5H₂O) under normal conditions, which is the most common commercial form.
Sodium Thiosulfate makes it chemically important in both industrial and laboratory processes.
Chemically, sodium thiosulfate acts as a reducing agent because it can donate electrons and convert reactive oxidizing species into less harmful forms, such as converting iodine into iodide ions.
It also forms complexes with certain metals, which is useful in processes like photographic fixing.
Sodium Thiosulfate makes it versatile in coordination and redox chemistry.
Physically, it is a colorless or white crystalline substance that dissolves easily in water but is insoluble in most organic solvents, and it remains stable under normal storage conditions but can decompose under strong acids to produce sulfur dioxide and elemental sulfur.
Sodium Thiosulfate decomposition behavior is important for understanding its storage and handling requirements.
Sodium Thiosulfate makes it stable but chemically sensitive under specific conditions.
Sodium Thiosulfate is best described as a water-soluble inorganic reducing agent widely used in medical treatment, chemical neutralization, photography, and analytical chemistry.
Its ability to neutralize oxidizing agents and bind to reactive species makes it highly useful across multiple scientific fields.
Sodium Thiosulfates safety profile and versatility make it one of the most important sulfur-containing salts in practical chemistry.
Sodium thiosulfate (alone or in combination with sodium nitrite) is useful in the treatment of cyanide toxicity.
It has been touted for use in treating arsenic or other heavy metal poisonings, but its efficacy is in question for these purposes.
Sodium Thiosulfate is relatively non-toxic and inexpensive, it may be tried to treat arsenic poisoning. When used in combination with sodium molybdate, sodium thiosulfate may be useful for the treatment of copper poisoning.
Sodium thiosulfate is an important compound in redox chemistry because it acts as a moderately strong reducing agent that can selectively react with oxidizing agents without being overly reactive under normal conditions, which makes it useful for controlled chemical reactions in both laboratory and industrial environments.
Its sulfur atoms in different oxidation states allow it to undergo oxidation to sulfate while reducing other substances.
This makes it highly useful in analytical and environmental chemistry.
In aqueous solution, sodium thiosulfate can form complexes with certain metal ions such as silver, copper, and gold, which is why it is used in processes involving metal extraction, photographic chemistry, and specialized coordination reactions.
These complexes can increase the solubility of otherwise insoluble metal salts.
Sodium Thiosulfate makes it important in coordination and applied inorganic chemistry.
In acidic conditions, sodium thiosulfate is unstable and decomposes to produce elemental sulfur, sulfur dioxide, and water, which is why it must not be mixed with strong acids during storage or handling.
Sodium Thiosulfate decomposition reaction is also used as a classic laboratory demonstration of precipitation and reaction kinetics.
This makes it useful for both safety considerations and teaching chemistry concepts.
In medical chemistry, sodium thiosulfate has a protective role against oxidative stress and toxic compounds because it can neutralize reactive chemical species and support detoxification pathways in the body, especially in cases of severe poisoning or metabolic imbalance.
It is often used in combination therapies where multiple detoxification steps are required.
Sodium Thiosulfate makes it valuable in clinical toxicology.
Melting point: 48 °C
Boiling point: 100 °C
bulk density: 1350 kg/m3
Density: 1.01 g/mL at 25 °C
storage temp.: Store at +5°C to +30°C
solubility: Immiscible with alcohol; soluble in water; insoluble in alcohol
form: solid
Specific Gravity: 1.667
color: white
pH: 6.0–8.5 (25℃, 50 mg/mL in H2O)
Water Solubility: soluble in water
Sensitive: hygroscopic
Merck: 14,8694
Stability: stable. Incompatible with strong acids, strong oxidizing agents, iodine, mercury
Cosmetics Ingredients Functions: REDUCING
InChI: 1S/2Na.H2O3S2/c;;1-5(2,3)4/h;;(H2,1,2,3,4)/q2*+1;/p-2
InChIKey: AKHNMLFCWUSKQB-UHFFFAOYSA-L
SMILES: [Na+].[Na+].[O-]S([O-])(=O)=S
LogP: -0.428 (est)
Sodium Thiosulfate plays an important role in detoxification chemistry because it can neutralize toxic oxidizing substances such as chlorine, hypochlorite, and iodine, which makes it valuable in both medical emergency treatments and industrial safety procedures.
This detoxifying ability comes from its strong electron-donating behavior in redox reactions.
Sodium Thiosulfate makes it useful in both biological and environmental protection contexts.
Sodium Thiosulfate is used as an antidote for cyanide poisoning in combination with other agents, where it helps convert toxic cyanide into less harmful thiocyanate that can be excreted by the body.
It is also used to treat certain side effects of chemotherapy and calcification disorders in specialized clinical settings.
Sodium Thiosulfate makes it an important compound in emergency and therapeutic medicine.
In photography, sodium thiosulfate is historically known as a “fixing agent” in film processing, where it dissolves unreacted silver halides from photographic emulsions to make images permanent and light-stable.
This process is essential for developing traditional film and photographic prints.
Sodium Thiosulfate makes it a key compound in classical imaging technology.
Sodium Thiosulfate is widely used in iodometric titrations, where it reacts precisely with iodine to allow accurate measurement of oxidizing agents in a solution.
This reaction is highly reliable and forms the basis for many quantitative chemical analyses.
Sodium Thiosulfate makes it important for laboratory measurement and quality control.
In environmental applications, sodium thiosulfate is used to dechlorinate water systems, such as neutralizing chlorine in aquarium water, wastewater treatment, and laboratory water preparation.
It is effective because it rapidly converts chlorine into harmless chloride ions.
Sodium Thiosulfate makes it valuable in water treatment and environmental safety.
Sodium thiosulfate has two forms as anhydrous sodium thiosulfate (Na2S2O3) and sodium thiosulfate pentahydrate (Na2S2O3·5H2O), the latter is also known as soda and Hyperion.
A molecular weight is 158.11 and 248.18 respectively.
Anhydrous sodium thiosulfate is an opaque crystalline powder.
Sodium Thiosulfate is odorless, salty taste, soluble in water, insoluble in ethanol.
It decomposes in acidic solution, has a strong reduction, easily absorbs moisture.
Sodium Thiosulfate is odorless, colorless and transparent monoclinic crystals or granules.
The relative density is 1.685. The melting point is 48 ℃.
Sodium Thiosulfate loses all crystal water at 100 ℃, and decomposes above 100 ℃.
Sodium Thiosulfate is easily weathered in dry and hot air, slightly deliquescence in the hot and humid air.
Sodium Thiosulfate is soluble in water and turpentine, insoluble in ethanol, decomposes in case of strong acid.
Prolonged exposure in the air, it is easily oxidated and carbonized by oxygen and carbon dioxide.
Sodium Thiosulfate is an important chemical commodity that is known to photographers as "hypo".
Sodium Thiosulfate can be prepared by the reaction of sodium sulphite and the bisulphite with H2S: 2Na2S03 + 2NaHS03 + 2H2S -> 3Na2S203 + 3H20
It can also be prepared by the reaction of sulphur with sodium sulphite above 60 °C
Na2SO3 + S -> Na2S2O3 and by the reaction of H2S and permanganate.
Sodium thiosulphate decomposes at 310°C to form sulphur and Na2S03 , and at 400°C to form Na2S4 and Na2S.
Sodium Thiosulfate absorbs S02 to form free sulphur and Na2S04 .
Sodium Thiosulfate forms many hydrates and their solubility relationships are quite complex.
Sodium Thiosulfate is a common reducing agent.
It reduces iodine to iodide anion forming sodium tetrathionate.
This reaction is utilized in the so-called iodometric titration: 2S2O32ˉ + I2 → S4O62ˉ + 2Iˉ
Sodium thiosulfate reacts with chlorine to form sodium bisulfate and hydrochloric acid. This reaction removes chlorine from aqueous solutions:Na2S2O3 + 4Cl2 + 5H2O → 2NaHSO4 + 8HCl
Sodium thiosulfate reacts with hydrochloric acid, decomposing to sulfur and sulfur dioxide: Na2S2O3 + 2HCl → 2NaCl + S + SO2 + H2O.
In environmental chemistry, it plays a role in chlorine removal from water systems because it reacts rapidly with free chlorine and hypochlorite, converting them into harmless chloride ions and sulfate-related products, which helps protect aquatic organisms and improve water safety.
This reaction is widely used in aquaculture, wastewater treatment, and laboratory water preparation.
Sodium Thiosulfate makes it important for environmental protection and water management.
In industrial processing, sodium thiosulfate is sometimes used in gold leaching and metal recovery processes as a safer alternative to cyanide-based extraction systems, where it helps dissolve and recover precious metals under controlled conditions.
Although less common than cyanide processes, it is considered more environmentally friendly in certain applications.
Sodium Thiosulfate makes it relevant in sustainable metallurgy.
Uses Of Sodium Thiosulfate:
Sodium Thiosulfate is Used in manufacture of the fixing powder and preparation of the photographic industry fixer, desiccant.
Used as a reducing agent of dichromate in leather tanning industry.
Sodium Thiosulfate is an important inorganic chemical raw material.
Sodium Thiosulfate can be used in the synthesis of pesticides Bisultap, Thiosultap disodium, CARTAP and so on.
Sodium Thiosulfate is used as analytical reagents, mordant and fixer.
Used as new insecticides, with stomach poisoning, uptake and contact action effects, it can prevent and treat rice yellow stem borer, stem borer, leaf roller, rice thrips and vegetables, fruit pests.
With uptake and strong contact, stomach poisoning effects, it can prevent and treat various rice pests and vegetables, fruit pests.
Sodium Thiosulfate is used as the chlorine removal agent for Pulp and cotton fabric bleached, as chelating agents, anti-oxidants in the food industry, as detergents, disinfectants in the pharmaceutical industry.
Sodium Thiosulfate is used as chelating agents, antioxidants, anti-browning agent, as the dechlorination agent of chlortetracycline hydrochloride (or chlortetracycline) chilled with ice, dechlorination reaction is as follows.
More chlorine content will cause side reactions of free sulfur, so only used for very dilute concentrations of chlorine.
Used as salt chelating agent, limited content is 0.1% or less.
Sodium Thiosulfate is a common analytical reagent used in iodometric titration to analyze chlorine, bromine, and sulfide.
Other uses are in bleaching paper pulp, bleaching straw, ivory, and bones, for removing chlorine from solutions, silver extraction from its ores, a mordant in dyeing and printing textiles, and as an antidote to cyanide poisoning.
Another major application is in photography, where it is used as a fixer to dissolve unchanged silver salts from exposed negatives.
Sodium Thiosulfate is used primarily as a medicament against cyanide poisoning, able to convert cyanide into thiocyanate, a reaction which is catalyzed by the enzyme Rhodanese. Antioxidant.
Sodium thiosulfate is used as a reducing agent, detoxifying agent, medical treatment compound, photographic fixer, and analytical reagent because of its ability to neutralize oxidizing chemicals and participate in controlled redox reactions.
Sodium Thiosulfates high solubility and stability in water make it easy to use in both laboratory and industrial systems.
This makes it a versatile compound across chemistry, medicine, and industry.
In medicine, it is used as an antidote for cyanide poisoning and in certain treatments for calciphylaxis and chemotherapy-related complications, where it helps reduce toxic effects and support detoxification processes.
It works by converting harmful compounds into less toxic or excretable forms in the body.
Sodium Thiosulfate makes it important in emergency and clinical care.
In photography, it is used as a fixing agent in film development, where it removes unreacted silver halides to stabilize images and prevent further exposure to light.
This process is essential for producing permanent photographic prints in traditional film photography.
Sodium Thiosulfate makes it historically significant in imaging technology.
In laboratory chemistry, it is used in iodometric titrations and redox analysis, where it provides precise measurement of oxidizing agents such as iodine.
Its predictable reaction behavior makes it ideal for quantitative chemical analysis.
Sodium Thiosulfate makes it important in analytical and research chemistry.
In environmental and industrial applications, it is used for dechlorination of water and neutralization of oxidizing agents, particularly in wastewater treatment and laboratory water preparation.
It safely converts chlorine into chloride ions, reducing toxicity and chemical reactivity.
Sodium Thiosulfate makes it useful in water treatment and environmental safety systems.
Sodium thiosulfate is used as a reducing agent, detoxifying compound, analytical reagent, photographic fixer, and water treatment chemical because of its ability to neutralize oxidizing agents and form stable reaction products in aqueous systems.
Its safety profile and solubility make it practical for both laboratory and industrial use.
Sodium Thiosulfate makes it a widely used compound in chemistry and applied sciences.
In medicine, it is used as an antidote for cyanide poisoning and in treatments for calciphylaxis and other conditions involving abnormal calcification or oxidative stress, where it helps convert toxic compounds into less harmful forms.
It supports detoxification processes by enhancing chemical neutralization pathways in the body.
Sodium Thiosulfate makes it important in emergency medicine and specialized therapy.
In photography, it is used as a fixing agent that removes unreacted silver halides from photographic film and paper, making images permanent and resistant to further light exposure.
Sodium Thiosulfate process is essential in traditional film development and printing techniques.
This makes it historically and technically important in imaging science.
In analytical chemistry, it is widely used in iodometric titrations and quantitative redox analysis, where it reacts in a predictable way with iodine to determine concentrations of oxidizing agents.
This allows accurate and reproducible measurements in laboratory experiments.
Sodium Thiosulfate makes it essential in chemical analysis and quality control.
Sodium Thiosulfate is used for dechlorination of water in aquariums, wastewater systems, and laboratory settings, where it neutralizes chlorine and hypochlorite to make water safe for biological systems.
This prevents toxic effects on aquatic organisms and sensitive chemical processes.
Sodium Thiosulfate makes it important in environmental safety and water treatment.
Safety Profile Of Sodium Thiosulfate:
Sodium Thiosulfate is generally considered a low-toxicity and relatively safe chemical under normal handling conditions, but it can still pose risks if it is inhaled as dust, ingested in large amounts, or improperly mixed with incompatible substances, especially strong acids.
Its main hazards are related to irritation and chemical decomposition rather than high systemic toxicity.
Sodium Thiosulfate makes it safer than many other industrial inorganic chemicals but still requiring basic precautions.
Direct contact with sodium thiosulfate solutions or powder may cause mild skin and eye irritation, particularly in sensitive individuals or after prolonged exposure, even though it is not strongly corrosive or aggressively reactive.
Eye exposure can lead to redness, discomfort, or temporary irritation that usually resolves after rinsing with water.
Sodium Thiosulfate makes protective gloves and eye protection advisable during handling.
If sodium thiosulfate is inhaled as dust, it may cause respiratory tract irritation, coughing, or throat discomfort, especially in poorly ventilated environments or during large-scale handling of dry powder.
Although it is not highly toxic by inhalation, fine particles can still irritate mucous membranes.
Sodium Thiosulfate makes dust control and ventilation important in industrial settings.
One of the most significant chemical hazards occurs when sodium thiosulfate is exposed to strong acids, where it decomposes to release sulfur dioxide gas, elemental sulfur, and other sulfur-containing byproducts that can be irritating or harmful when inhaled in high concentrations.
Sulfur dioxide is particularly irritating to the respiratory system and can cause breathing difficulties in sensitive individuals.
Sodium Thiosulfate makes acid contact a key incompatibility hazard.
