Ruthenium: Osmiridium Opened with Barium Peroxide and Nitrate, Separated as Ruthenate (Deville and Debray, Roscoe 1913)

Barium peroxide and nitrate break up osmiridium. In acid the osmium distils off as tetroxide, which is kept for osmium. The ruthenium rides with the iridium salt until a nitre-and-potash fusion turns it into orange-red potassium ruthenate, from which nitric acid throws down the oxide. Result: ruthenium, fused in the oxy-hydrogen flame; and a distillate of osmium tetroxide for making osmium. Source: Roscoe and Schorlemmer, A Treatise on Chemistry vol. 2 (1913), pp. 1319-1320, after Deville and Debray. Not given: absolute amounts and most temperatures. Osmium tetroxide vapour is highly poisonous: it attacks the eyes. Picture drawn by Youblob.