Ammonium Chloriridate, (NH₄)₂IrCl₆

Ammonium Chloriridate, (NH₄)₂IrCl₆, is readily produced by decomposing the sodium salt with ammonium chloride in aqueous solution. It crystallises in regular octahedra, reddish black in colour, and but slightly soluble in cold water, although appreciably soluble in hot. It does not dissolve in solutions of ammonium or potassium chloride. When evaporated with aqua regia, the ammonia is expelled, iridium tetrachloride remaining. Heated to 440° C. in a current of chlorine the tetrachloride is first formed and decomposes into the anhydrous trichloride.

Ammonium chloriridate is isomorphous with the corresponding chlorplatinate, (NH₄)₂PtCl₆.

Its solubility in water is given as follows:

Temperature ° C	14.4	26.8	39.4	52.2	61.2	69.3
Grams of (NH4)2IrCl6 per 100 grams solution	0.694	0.899	1.124	1.583	2.068	2.746

The solubility of the salt in water between these temperatures is given approximately by the expression:

Solubility = 0.680 + 0.0004t(t - 10).

Rubidium Chloriridate, Rb₂IrCl₆, is obtained by mixing a solution of iridium tetrachloride with excess of rubidium chloride, whereby a deep red, crystalline precipitate is obtained. The salt dissolves slightly in hot water to yield an orange-red solution.