| Product Name | Sodium Thiosulfate |
| Cas Number | 7772-98-7 |
| Formula | Na2S2O3 |
| Molar Mass | 158.11 g/mol |
| Pub Chem Cid | 24477 |
| Drug Bank | DB01334 |
| Chem Spider | 22821 |
| Bioavailability | 100% |
| Protein Binding | Not available |
| Metabolism | Metabolized to sulfate which is excreted in urine |
| Elimination Halflife | 4 hours |
What is Sodium Thiosulfate, and what are its main uses?
Sodium thiosulfate (Na₂S₂O₃) is an inorganic compound commonly used in various industrial, medical, and laboratory applications. It’s a white, crystalline substance that dissolves well in water and is known for its ability to neutralize and dechlorinate. In water treatment, sodium thiosulfate removes residual chlorine, making it crucial for treating drinking water and aquariums. In photography, it’s used as a "fixer" to stabilize photographic film and paper after developing. In medicine, sodium thiosulfate is an antidote for cyanide poisoning and can help treat certain side effects of chemotherapy, such as cisplatin toxicity. Due to its versatility, sodium thiosulfate is highly valued across multiple fields.
How does Sodium Thiosulfate function as an antidote to cyanide poisoning?
Sodium thiosulfate acts as an antidote to cyanide poisoning by facilitating the detoxification of cyanide in the body. Cyanide inhibits cellular respiration by binding to enzymes in cells, preventing oxygen utilization. Sodium thiosulfate provides sulfur, which reacts with cyanide in the presence of the enzyme rhodanese, converting it to a less toxic compound, thiocyanate, which is then excreted in the urine. This detoxification process helps restore cellular respiration and reduces the toxicity of cyanide. In medical emergencies, sodium thiosulfate is often administered intravenously alongside other antidotes, like hydroxocobalamin, to enhance its effectiveness and improve survival outcomes.
Why is Sodium Thiosulfate used in photography, and how does it work as a fixer?
In photography, sodium thiosulfate serves as a fixer in the photographic development process, specifically for film and paper. After the film or paper has been exposed and developed, unreacted silver halide crystals remain, which would otherwise darken over time if left untreated. Sodium thiosulfate "fixes" the image by dissolving these unreacted silver halides, leaving only the developed silver image. This stabilizes the image, preventing it from further exposure to light and preserving it over time. This fixing process is essential for ensuring long-lasting photographs, making sodium thiosulfate a cornerstone in traditional photography.
How is Sodium Thiosulfate used in water treatment and dechlorination?
Sodium thiosulfate is widely used in water treatment to neutralize chlorine and chloramine, which are commonly added to disinfect water. Chlorine, while effective as a disinfectant, can be harmful to aquatic life and sensitive environments when present in excess. Sodium thiosulfate neutralizes chlorine by converting it into chloride ions and sulfate, both of which are non-toxic. This dechlorination process is especially important in treating water for fish tanks, aquariums, and in certain industrial water uses. Its ability to efficiently neutralize chlorine makes it an ideal choice for ensuring safe water in various applications, from environmental protection to fishkeeping.
What are the safety considerations when handling Sodium Thiosulfate?
While sodium thiosulfate is generally considered safe and non-toxic, some precautions are necessary, especially in high concentrations or industrial settings. Direct contact with sodium thiosulfate may cause mild skin or eye irritation, so gloves and eye protection are recommended when handling the compound in bulk. Inhalation of its dust may irritate the respiratory tract, so good ventilation or a dust mask is advisable in environments where dust exposure might occur. While sodium thiosulfate is typically safe, anyone using it for medical purposes or in clinical settings should do so under the guidance of healthcare professionals.
What role does Sodium Thiosulfate play in aquaculture and aquarium maintenance?
In aquaculture and aquarium care, sodium thiosulfate is essential for making water safe for aquatic life by removing chlorine and chloramine, which are toxic to fish and invertebrates. Chlorine and chloramine, used in municipal water supplies as disinfectants, can damage the gills and tissues of aquatic animals, potentially leading to death. By adding sodium thiosulfate to the water, aquarists can neutralize these harmful chemicals, rendering the water safe for fish and other aquarium inhabitants. Sodium thiosulfate is easy to use, cost-effective, and reliable, making it a popular dechlorination agent in fishkeeping.
How does Sodium Thiosulfate help in the treatment of calciphylaxis?
Calciphylaxis is a rare, painful condition seen primarily in patients with kidney disease, where calcium accumulates in the blood vessels, leading to skin ulcers and tissue damage. Sodium thiosulfate is used in treating calciphylaxis because it has vasodilatory and anti-calcification effects. When administered intravenously, sodium thiosulfate helps dissolve calcium deposits, thus reducing pain and slowing the progression of tissue necrosis. Additionally, it has antioxidant properties that may protect tissues. While sodium thiosulfate shows promise in treating calciphylaxis, further research is ongoing, and it is used under medical supervision due to the complexity of the condition.
What is the role of Sodium Thiosulfate in neutralizing halogens, and how does it work?
Sodium thiosulfate is an effective neutralizer for halogens such as chlorine, bromine, and iodine. Its reducing properties allow it to act as an electron donor, reacting with halogens to convert them into harmless halide ions. In this process, sodium thiosulfate donates electrons to the halogen atoms, reducing them to halide ions (e.g., Cl⁻ from Cl₂). This reaction is particularly useful in scenarios where excess halogens need to be removed, as in water treatment or laboratory settings. Sodium thiosulfate’s efficiency in halogen neutralization has made it a standard tool in water management and chemical neutralization processes.
How is Sodium Thiosulfate used in laboratory chemistry, specifically in iodometric titrations?
In analytical chemistry, sodium thiosulfate is used in iodometric titrations, a method for determining the concentration of oxidizing agents. When sodium thiosulfate is added to a solution containing iodine, it reacts with the iodine, reducing it to iodide ions and turning the solution colorless. By measuring the volume of sodium thiosulfate solution required to complete the reaction, chemists can calculate the concentration of the original oxidizing agent. This titration method is valuable for analyzing various substances, such as chlorine levels in water and peroxide levels in solutions. Sodium thiosulfate’s reliable reactivity with iodine makes it a staple in analytical chemistry.
Are there any alternative compounds to Sodium Thiosulfate for dechlorination and medical use?
For dechlorination, sodium metabisulfite and ascorbic acid are sometimes used as alternatives to sodium thiosulfate, especially in water treatment and fishkeeping. Both compounds neutralize chlorine effectively, though sodium thiosulfate remains popular due to its cost-effectiveness and minimal impact on water chemistry. In medical settings, especially for treating cyanide poisoning, hydroxocobalamin and nitrites can serve as alternatives, depending on the situation. While sodium thiosulfate has specific advantages, alternative compounds may be selected based on cost, availability, or specific safety considerations.
