RUTHENIUM (ante) is in that portion of platinum ore which is called osmiridium. When crude platinum is dissolved in nitro-muriatic acid a small Quantity of a gray, scaly, metallic substance remains behind. This is a native alloy of iridium, osmium, and ruthenium. This is called scaly osmiridium, and is the variety which is the source of extraction of ruthenium. Another variety, also a residue of the same process of digestion of the platinum ore in nitro-muriatic acid, is granular, and rich in iridium and rhodium. To obtain ruthenium, scaly osmiridium is heated to bright red ness in a porcelain tube, through which a current of air freed from carbonic acid and organic matter is drawn by an aspirator. This operation produces oxidation of the osmium and ruthenium, the osmium oxide being carried forward and condensed in a solution of caustic potash, while the oxide of ruthenium remains behind, together with the iridium. This residue is then fused with caustic potash, the mass treated with water and allowed to stand in a corked bottle about two hours to clarify. After precipitation an orange-colored solution of rutheniate of potassium is obtained, which, when neutral ized With nitric acid, deposits velvet-black scsquioxide of ruthenium, which, when washed, dried, and ignited in hydrogen, yields the metal. Thus prepared, ruthenium
is in porous lumps having a specific gravity of 8.6. It is the most refractory of all metals except osmium, but it may be fused by placing it in the hottest part of the oxyhydrogen flame (see OXYHYDROGEN BLOW-PIPE). After fusi an its density is 11.4. It is attacked with difficulty by nitro-muriatic acid, but will yield to oxidizing reagents more readily than platinum, or even silver; therefore potash is used in extracting it as above described. There are three chlorides of ruthenium. Ru Ru and Ru Cl,. There are five oxides, RuO, RuO,, and Rua,. The tetroxide, like the tetra chloride, is known only in combination. Sulphureted hydrogen gas, when passed into a solution of either of the chlorides of ruthenium, forms a precipitate of sulphide and oxysulphide of ruthenium mixed with free sulphur. The blue solution of the dichloride yields with sulphureted hydrogen a dark-brown sesquisulphide, When sulphu reted hydrogen is passed for a long time into a solution of the trichloride, disulphide of ruthenium is precipitated, which becomes dark brown by calcination There are several ammoniacal salts.