K3CoCN6

K3CoCN6, also called potassium hexacyanocobaltate(III), is the potassium salt of the hexacyanocobaltate(III) anion [Co(CN)6]3−. In solid form it consists of the octahedral [Co(CN)6]3− complex anion accompanied by three potassium counterions. The cobalt center is in the +3 oxidation state and is coordinated by six cyanide ligands through carbon atoms, giving a highly symmetric octahedral geometry.

The compound is typically encountered as a readily soluble inorganic salt in water; solutions contain the [Co(CN)6]3− ion and K+ counterions. It is part of the family of transition-metal cyanometallates and is used in coordination chemistry and materials science as a stable, well-characterized precursor to other cobalt-cyanide compounds.

Preparation generally follows standard cyanometallate methods, joining cobalt(III) sources with cyanide under conditions that promote formation of the hexacyanocobaltate(III) framework and subsequent association with potassium ions. It can be used as a starting material to synthesize cobalt cyanide-based coordination polymers and can participate in redox chemistry studies of cobalt centers in cyanide environments.

Safety: K3CoCN6 contains cyanide ligands and should be handled with appropriate precautions. Acidic conditions can liberate toxic hydrogen cyanide; use in a well-ventilated area with personal protective equipment and proper waste disposal. It is incompatible with strong oxidants.

See also: K3[Fe(CN)6], related Prussian blue chemistry.