Cyanometallate

Cyanometallate is a chemical term referring to a coordination complex containing cyanide ligands coordinated to a central metal atom. These complexes are often formed by transition metals, which readily form stable bonds with the cyanide ion (CN⁻). The cyanide ligand is a strong field ligand, meaning it causes a large splitting of the d-orbitals in the metal ion, leading to low-spin complexes. This property influences their magnetic and spectroscopic characteristics.

Common examples of cyanometallates include ferrocyanides and ferricyanides, which contain iron(II) and iron(III) respectively. Prussian blue, a pigment with the formula Fe₄[Fe(CN)₆]₃·xH₂O, is a well-known example of a cyanometallate. Other metals like cobalt, nickel, and platinum also form a variety of cyanometallate complexes with diverse structures and properties.

The synthesis of cyanometallates typically involves reacting a soluble metal salt with an alkali metal cyanide, such as potassium cyanide. The resulting complexes can have varying charges depending on the oxidation state of the metal and the number of cyanide ligands. These compounds find applications in various fields, including analytical chemistry, pigment production, and as precursors in the synthesis of other materials. Some cyanometallates exhibit interesting electrochemical and photochemical behavior.