Osmic Acid, H₂OsO₄

Osmic Acid, H₂OsO₄, does not appear to have been prepared. The black compound obtained by acting upon potassium osmate with dilute nitric acid was believed by Moraht and Wischin to be correctly represented by the formula H₂O.OsO₃ or H₂OsO₄, but this has not been confirmed by the more recent researches of Ruff and Bornemann, who regard the product as the hydrated dioxide. Further research is necessary to elucidate this point.