Ferricyanide is a chemical compound that contains iron in its +3 oxidation state and cyanide ions. It is often found in the form of potassium ferricyanide, which is a bright red crystalline solid. This compound is commonly used in various applications, including photography, electrochemistry, and as a reagent in laboratories. In addition to its practical uses, ferricyanide is notable for its role in the formation of Prussian blue, a pigment that has historical significance in art and industry. It is also used in the detection of certain metals and in the synthesis of other chemical compounds.