Nátriumtioszulfát

Nátriumtioszulfát, also known as sodium thiosulfate, is a chemical compound with the formula Na₂S₂O₃. It is commonly found in its hydrated form, Na₂S₂O₃·5H₂O, which is a crystalline solid. In its pure form, it is a white, crystalline powder, although commercial samples are often off-white. It is highly soluble in water but insoluble in alcohol.

Sodium thiosulfate is widely used in various applications. In photography, it is used as a fixer, removing unexposed silver halide crystals from photographic film and paper after development. This process is essential for creating a stable and permanent image. In medicine, it is used as an antidote for cyanide poisoning, where it reacts with cyanide ions to form less toxic compounds. It is also employed in the treatment of skin conditions like fungal infections and itchy rashes.

Industrially, sodium thiosulfate is utilized in water treatment to remove chlorine. It acts as a dechlorinating agent, neutralizing residual chlorine in drinking water and wastewater. It also finds use in the textile industry as a bleaching agent and in the leather tanning process. In analytical chemistry, it is used in iodometry, a method for determining the concentration of oxidizing agents.

Sodium thiosulfate is generally considered safe to handle, but like any chemical, appropriate safety precautions should be taken. It can cause mild irritation upon contact with skin or eyes. When dissolved in water, it forms neutral solutions.