Potassium ferricyanide

Potassium ferricyanide is the red crystalline salt K₃[Fe(CN)₆], containing ferricyanide ions with iron in the +3 oxidation state. It serves as a mild oxidizing agent and laboratory reagent.

Ferricyanide: The [Fe(CN)₆]³⁻ coordination ion, with iron in the +3 oxidation state. This anion is the active oxidizing species in the salt.
Cyclic voltammetry: An electrochemical method that measures current while electrode potential is swept forward and backward. Ferricyanide is a common probe for testing electrode behavior and mass transport.
Potassium ion: The positively charged K⁺ ion formed when a potassium atom loses one electron. Three potassium ions balance the charge of each ferricyanide ion.
Sodium ferricyanide: The sodium salt Na₃[Fe(CN)₆], containing the same ferricyanide ion as potassium ferricyanide. It provides the same anion with sodium rather than potassium counterions.
Ferrocyanide: The [Fe(CN)₆]⁴⁻ coordination ion, with iron in the +2 oxidation state. It is the reduced product formed when ferricyanide accepts an electron.
Prussian blue: A deep-blue iron(III) hexacyanoferrate pigment and coordination solid. Ferricyanide reacts with iron salts to produce this historically important blue material.
Iron(III): The +3 oxidation state of iron, commonly found in ionic and coordination compounds. Iron has this oxidation state in the ferricyanide ion.
Potassium cyanide: The highly toxic ionic compound KCN, composed of potassium and free cyanide ions. Despite sharing potassium and cyanide groups, it is not the same compound or coordination ion.
Redox reaction: A chemical reaction involving transfer of electrons between substances. Ferricyanide oxidizes other compounds through electron transfer.
Cyanotype: A photographic printing process that creates cyan-blue images through light-driven iron chemistry. Ferricyanide is a component of the light-sensitive cyanotype sensitizer.

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Sodium thiosulfateCompared with: It can bleach metallic silver in photographic operations, opposite to thiosulfate's role in dissolving silver salts.