Osmium iodide refers to compounds of osmium with the formula OsIn. Several have been mentioned in the literature, but only the triiodide has been verified by X-ray crystallography. [1] [2]
Osmium(I) iodide is the iodide of osmium with the formula OsI. It is a metallic grey solid produced by the reaction of osmium tetroxide and hydroiodic acid heated in a water bath for 48 hours in a carbon dioxide atmosphere. This compound is amorphous. [2]
Osmium(II) iodide is the iodide of osmium with the formula OsI2. It is a black solid [3] produced by the reaction of osmium tetroxide and hydroiodic acid at 250 °C in nitrogen: [2]
This compound decomposes in contact with water. [3]
Osmium(III) iodide is the iodide of osmium with the formula OsI3. This black solid is produced by heating hexaiodoosmic acid(H2OsI6). [2] This compound is insoluble in water. [3]
What was claimed to be osmium(IV) iodide was produced by the reaction of osmium dioxide and hydroiodic acid. [4] However on attempted reproduction, this substance was found to be hexaiodoosmic acid H2OsI6. When heated this did not form a tetraiodo compound, and instead formed mono, di, and tri-iodo osmium compounds. The ammonium salt, (NH4)2OsI6, is known. [2]
When potassium iodide is added to a solution containing osmium tetroxide and hydrochloric acid, a green solution of H[OsI5(H2O)] is obtained, which also contains potassium hexaiodoosmate K2OsI6 and a mixed halidoosmate of the type K2OsClxIx. [5]