NH43FeCN6

NH43FeCN6 refers to the ammonium salt of ferricyanide, with the formula (NH4)3[Fe(CN)6]. It is commonly called ammonium ferricyanide or ammonium hexacyanoferrate(III). In the solid, the ferricyanide anion [Fe(CN)6]3− carries a −3 charge and is balanced by three NH4+ cations; the anion features an octahedral Fe(III) center coordinated by six cyanide ligands. The compound forms colorless to white crystalline material and is soluble in water, producing an aqueous ferricyanide solution.

Preparation generally involves metathesis between aqueous solutions containing a soluble ferricyanide source and an ammonium salt, followed by crystallization to isolate the neutral salt (NH4)3[Fe(CN)6]. The solid is typically handled as a water-soluble salt suitable for laboratory use.

Reactivity and applications center on the ferricyanide/ferrocyanide redox couple. The [Fe(CN)6]3−/4− system is a classic mild redox mediator used in electrochemistry and has applications as an oxidizing agent in selective organic and inorganic transformations. Ammonium ferricyanide can also act as a precursor in the synthesis of Prussian blue pigments when reacted with ferrous iron under appropriate conditions. In analytical contexts, ferricyanide reagents serve in qualitative tests related to reducing agents and iron speciation.

Safety considerations are similar to other ferricyanide salts. The compound is of relatively low acute toxicity, but cyanide ligands are tightly bound and should not be released. Handle the solid with appropriate precautions to avoid inhalation of dust and contact with skin or eyes, and dispose of waste according to applicable regulations.