Osmyl Tetra-ammine Chloride, OsO₂(NH₃)₄Cl₂

Osmyl Tetra-ammine Chloride, OsO₂(NH₃)₄Cl₂, and is obtained as a yellow, crystalline precipitate when ammonium chloride is added to aqueous potassium osmate. It is but slightly soluble in water, and boiling water decomposes it into osmium tetroxide and osmium di- ammine hydroxide. Its solution gives a violet coloration with potassium ferrocyanide, a reaction that may be utilised for the detection of osmium. It is insoluble in alcohol and in hydrochloric acid. When heated it decomposes completely, yielding a mass of spongy osmium.

The corresponding nitrate and sulphate are known.