hexacyanometallates

Hexacyanometallates are coordination compounds containing the hexacyanometallate anion, which has the general formula [M(CN)6]n-, where M is a metal atom and n is the charge of the complex anion. These anions are typically octahedral in geometry, with the metal atom at the center surrounded by six cyanide ligands. The cyanide ligands are bound to the metal through their carbon atoms. The charge of the anion depends on the oxidation state of the central metal atom. Common examples include ferrocyanide, [Fe(CN)6]4-, and ferricyanide, [Fe(CN)6]3-. Other metals can also form hexacyanometallates, such as cobalt, manganese, and chromium.

These compounds are often soluble in water and can form a variety of salts with different cations. Their properties vary widely depending on the central metal atom and the counterions. Some hexacyanometallates are colored, while others are colorless. They find applications in various fields. For instance, ferrocyanides are used as anti-caking agents in salt and in the production of pigments like Prussian blue. Ferricyanides are employed in photography and as oxidizing agents in analytical chemistry. Some hexacyanometallates have also been investigated for their potential in catalysis and as components in electrochemical devices. The stability of the cyanide ligand and the strong metal-ligand bond contribute to the unique properties of these complexes.