Iridium sesquichloride, IrC1 31 is obtained when one of the corresponding double chlorides is heated with concentrated sulphuric acid, the mixture being then thrown into water.
It forms double chlorides with the alkaline chlorides.
Two chlorides of copper are known, one a highly coloured substance, the other quite white.
In a series of repetitions of the experiment, by different observers, the following numbers were obtained for the ratio of the copper in the two chlorides: 1.98, 1.97, 2.03, 2.003, the mean value being 1.996.
They are soluble in water and give characteristic precipitates with platinic and auric chlorides, and with potassium ferrocyanide.