Ammonium thiosulfate

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Ammonium thiosulfate

Ammonium thiosulfate (chemical formula: (NH4)2S2O3) is an inorganic compound that is commonly used in the photographic industry for silver recovery and as a fertilizer in agriculture. It is a colorless or white crystalline solid with a slight sulfur odor. This compound is highly soluble in water, making it an effective source of sulfur and nitrogen for plant nutrition.

Properties

Ammonium thiosulfate has a molecular weight of 148.21 g/mol and decomposes before boiling. Its solubility in water is a key feature, allowing it to be easily applied in various agricultural and industrial processes. The compound acts as a reducing agent and can react with oxidizing agents.

Applications

Photographic Industry

In the photographic industry, ammonium thiosulfate is used as a fixing agent to dissolve unexposed silver halide crystals from photographic film or photographic paper, leaving behind the reduced metallic silver to form the image. This process is crucial for the development and stabilization of photographic images.

Agriculture

In agriculture, ammonium thiosulfate is valued as a liquid fertilizer. It provides a source of sulfur, which is the fourth major nutrient required by crops, following nitrogen, phosphorus, and potassium. The presence of sulfur is vital for the synthesis of essential amino acids and proteins in plants. Additionally, the nitrogen content in ammonium thiosulfate aids in plant growth and development. It is often applied through fertigation or as a foliar spray.

Environmental Impact

Ammonium thiosulfate is considered to be of low toxicity to the environment. However, like all chemicals, it should be used in accordance with safety guidelines to minimize any potential negative impacts on soil and water quality.

Safety

Handling ammonium thiosulfate requires standard safety precautions. It is advisable to wear protective clothing, gloves, and eye protection to prevent irritation. In case of contact, affected areas should be rinsed with plenty of water.

See Also

• Fertilizer
• Photographic processing
• Sulfur cycle