Potassium hexacyanoferrate(III) K₃[Fe(CN)₆]

Potassium ferricyanide, with the chemical formula K₃[Fe(CN)₆], is an inorganic compound belonging to the category of coordination compounds. The following is a detailed introduction about it:

Basic Properties

1. Appearance: Deep red crystals, highly soluble in water, yielding a yellow-green aqueous solution.

2. Oxidizing Property: Exhibits mild oxidizing behavior, particularly participating in redox reactions under light or acidic conditions.

3. Stability: Relatively stable in neutral or alkaline solutions; decomposes upon contact with acids to produce highly toxic substances. Avoid exposure to strong acids.

Main Applications

1. Laboratory Reagent:

   Used to detect Fe²⁺ (ferrous ions), forming a deep blue precipitate of Prussian blue (Fe₄[Fe(CN)₆]₃).

   Serves as an oxidizing agent or electron transfer mediator in electrochemistry.

2. Industrial Applications:

   Photographic Processes: Functions as a bleaching or toning agent (e.g., cyanotype printing).

   Metal Plating: Utilized in processes such as zinc or silver plating.

   Pigment Production: Synthesizes blue pigments like Prussian blue.

3. Other Uses:

   Blueprint Making: Reproduction of engineering drawings.

   Certain Food Additives: Acts as an anti-caking agent (must comply with safety standards).

Safety Precautions

Toxicity: Low toxicity, but decomposition products (e.g., HCN) are extremely hazardous. Avoid contact with acids and ensure proper ventilation during handling.

Protection: Wear gloves and goggles to prevent inhalation of dust or skin contact.

Storage: Store in a sealed, light-protected container away from acidic substances.

Difference from Potassium Ferrocyanide

Potassium ferrocyanide (K₄[Fe(CN)₆]) is the reduced form of potassium ferricyanide, exhibiting greater chemical stability. It is commonly used as an anti-caking agent in food (e.g., added to table salt as "potassium ferrocyanide"). The two should not be confused.

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