Potassium Hexachloroiridate(IV) is a reagent with biocatalytic activity
Iridium potassium chloride (K2IrCl6) is used as a black pigment to make black porcelain
kitchen and bathroom fixtures.
Black pigment (porcelain decoration). The iridium (III) salt is also known: K3IrCl6, greenishyellow.
Crystallise it from hot aqueous solution containing a few drops of HNO3 to keep it in the oxidised state. It forms small shiny red-black octahedral crystals which are dried at 100o and give a red powder on grinding [Grube in Handbook of Preparative Inorganic Chemistry (Ed. Brauer) Academic Press Vol II pp 1593-1594 1965].
