RUTHENIUM (Ru). This metal was shown to exist in platinum ores by Clauss in 1845. According to Deville and Debray, who have specially studied the metals associated with platinum, ruthenium may be prepared from the native osmido by mixing it, iu fine powder, with three parts of binoxide of barium and one of nitrate of baryta ; heating the whole to redness in a crucible far an hour ; treating the product with hydrochloric, nitric, and sulphuric acids consecutively ; precipi tating with chloride of ammonium ; igniting the precipitate ; • and finally fusing the residue with nitrate and hydrate of potash. From the rutheniate of potash thus formed, the teroxide of ruthenium, or ruthenic add may be precipitated by carbonic or nitric acids, and then reduced to the metallic state by heating in a current of hydrogen.
Ruthenium is only fusible with extreme difficulty. It has a blackish brown surface, and is hard and brittle like iridium. Its specific gravity is 11 to 1P4, and its equivalent 52.11.
Ruthenium and oxygen unite in four different proportions. Protoxidc (Ru0); sesquioxide the most stable of these oxides, formed on igniting the metal iu a current of air ; binoxide (Itu0,), obtained by roasting and igniting the bisulphide; and ruthenic acid pre pared as already described.
Ruthenium and sulphur. The sulphides of this metal are probably as numerous as the oxides, but they are very difficult of preparation.
Ruthenium and eh/crime form three compounds. The protochloride (RuCI) results from the ignition of the metal hi chlorine gas; it is insoluble in water or acids. The sesguiehloride is formed on dissolving the sesquioxide iu hydrochloric acid; and the bichloride (ItuCy, which exists as a rose-coloured double salt with chloride of potassium.
The salts of ruthenium are chiefly those of the sesquioxide. They have a yellow colour, and alkalies reprecipitate from their solutions the sesquioxide as a black powder. A sulphate, containing
has been obtained.
ItUTIC ACID. [Rum ("flour.] 1tUTIC GROUP. A cluster of chemical substances containing the elcctro-negative radical rutyi Hydride of rutyl (C.,H„0„ II) ratio or Capric aldehyd. This body forms the greater part of the volatile oil of the common rue. Murn, grareolens, in NAT. HIST. Div.] Its specific gravity is •837; boiling point from 442' Fahr. to 446° Fahr.; vapour density 5.83. It crystal lises in transparent plates at a few degrees below the freezing point of water ' • gives crystalline combinations with the alkaline bisul phites ; is but little acted uponjby sulphuric or hydrochloric acids, but is converted into rude add when placed in contact with nitric acid.
Rutic add or add. This acid may be obtained from sources other than just mentioned. It is one of the products of the saponification of butter ; it may be formed by the action of nitric acid upon oleic acid; it is contained in small quantity in cocoa-nut oil, and is also found in the oily matters that accompany the distillation of Scotch whiskey. From the latter source it is most conveniently obtained, though the operation is tedious and somewhat difficult.
Rutic acid is crystalline and colourless; it has an odour recalling that emitted from the skin of a goat, melts at 81° Fahr., is very solu ble in alcohol or ether, is not soluble in cold water, but is slightly so in hot water. It is monobasic and forms crystalline salts termed relates.
Ratio ether separates as an oily liquid on ing dry hydrochloric acid through a solution of rutic acid in a .lute alcohol. Its density is 0.862. Ammonia converts it into re:amide. The latter body crystallises in brilliant plates.