Na3FeCN6

Sodium ferricyanide, with the chemical formula Na3[Fe(CN)6], is the sodium salt of the hexacyanoferrate(III) anion [Fe(CN)6]3−. In the solid, three sodium ions balance the 3− charge of the octahedral [Fe(CN)6]3− complex, in which iron is in the +3 oxidation state and is coordinated by six cyanide ligands. In aqueous solution, the ferricyanide complex imparts an orange-red color to the solution.

Preparation of Na3[Fe(CN)6] is typically achieved by oxidizing the corresponding ferrocyanide salt Na4[Fe(CN)6] or other ferrocyanide sources, using oxidants such as chlorine, hypochlorite, or hydrogen peroxide, or via electrochemical oxidation of ferrocyanide in solution.

Properties of the compound include its solubility in water and its role as a mild oxidizing agent. The ferricyanide/ferrocyanide redox pair has a standard potential of about +0.36 V versus the standard hydrogen electrode, making it a useful redox mediator in various aqueous systems. The solid is generally stable under normal laboratory conditions, though strong reducing environments or strong acids can lead to changes in oxidation state or release of cyanide under extreme conditions.

Applications for sodium ferricyanide include its use as an oxidizing agent in inorganic and organic synthesis, as a redox mediator in electrochemical applications, and as a reagent in analytical chemistry and redox assays. It is typically handled like other cyanide-containing coordination complexes, with standard safety precautions appropriate for inorganic salts.

See also: ferricyanide, ferrocyanide, Na4[Fe(CN)6], K3[Fe(CN)6].