Hydrogen Iridicyanide, H₃Ir(CN)₆

Hydrogen Iridicyanide, H₃Ir(CN)₆, is conveniently prepared by treating its barium salt with the requisite quantity of dilute sulphuric acid. On shaking with ether a white crystalline deposit of hydrogen iridicyanide is obtained.

The crystals resemble those of their cobalt analogue, H₃Co(CN)₆, in that they are very soluble in water and exhibit a strongly acid reaction, readily decomposing carbonates. They combine with bases to form well-defined salts. Conductivity measurements of the potassium and barium salts show that they are not simply double cyanides, but salts of hydrogen iridicyanide.