Some Studies in Inorganic Complexes. IX. The Pyrolysis of Hexammineosmium(III) Salts

Abstract

A study has been made of the action of heat on the salts Os(NH₃)₆ISO₄ and Os(NH₃)₆X₃, in which X is bromide or iodide. The initial products are [OsI(NH₃)₅]SO₄ and [OsX(NH₃)₅]X₂ respectively. At higher temperatures the latter decompose into black double-halogen bridged complexes [(NH₃)₃XOsX₂0sX(NH₃)₃]X₂, while the sulphate forms a black residue of composition corresponding to Os(NH₃)₃ISO₄ but of unknown structure. Further heating results in oxidation to OsO₄ and halogen in all cases. The structures of the black halogen complexes as well as the monohalogenopentammineosmium(III) salts have been verified by magnetic and conductance measurements. However, since osmium(IV) shows a remarkable tendency towards maximum electron pairing, having a moment of 1.2-1.5 Bohr magnetons in most of its complexes, the black compounds could have the less symmetrical structure [Os(III)X(NH₃)₅][Os(IV)X₅NH₂].