Chem., 1905, 45, p. 166) by heating the crude metal (obtained by other processes) in a current of oxygen until all the osmium is volatilized as tetroxide.
The residue so obtained is then powdered and ignited with barium nitrate, which converts the iridium into its oxide and the osmium into barium osmiate.
The barium salt is extracted by water and boiled with nitric acid, when the osmium volatilizes in the form of its tetroxide.
Potassium osmichloride, K 2 OsC1 6, is formed when a mixture of osmium and potassium chloride is heated in a current of chlorine, or on adding potassium chloride and alcohol to a solution of the tetroxide in hydrochloric acid.
The various improvements in electric illuminants, such as the Nernst oxide lamp, the tantalum and osmium incandescent lamps, and improved forms of arc lamp, enclosed, inverted and flame arcs, are described under Lighting: Electric. Between 1890 and 1900, electric traction advanced rapidly in the United States of America but more slowly in England.
Chem., 1905 (2), 71, p. 45 2) by reducing osmium compounds with hydrazine hydrate in the presence of gum arabic.
The sesquioxide, Os203, results on heating osmium with an excess of the tetroxide.
Several oxides of osmium are known.
Seubert redetermined this constant for platinum, osmium and iridium; E.
The tetroxide, 0s04, is formed when osmium compounds are heated in air, or with aqua regia, or fused with caustic alkali and nitre.