560 Intelligence and Miscellaneous Articles. 



II. Sesquichloride of Ruthenium, Ru 2 Cl 3 , is obtained by dissolving 

 the sesquioxide, precipitated from the rutheniate of potash, in mu- 

 riatic acid, and evaporating to dryness. It is deliquescent, has a very 

 astringent non-metallic taste, like tannic acid ; and dissolves, leaving 

 behind the yellow basic compound, with a beautiful orange-red 

 colour in water and spirit. When heated it acquires the above- 

 mentioned green and blue colour. One of its most remarkable pro- 

 perties is that its dilute solution is decomposed by heat into free 

 muriatic acid and hydrated sesquioxide. This decomposition takes 

 place likewise at the ordinary temperature in the course of a few 

 days. 



Caustic and carbonated alkalies, as well as the tribasic phosphate 

 of soda, immediately produce in the solution of this salt a blackish- 

 brown precipitate of hydrated sesquioxide, which is not soluble in an 

 excess of the precipitant. Some unprecipitated metal is however 

 left in the solution. Solution of borax at first produces no precipi- 

 tate, but merely decolorizes the solution, which on the application 

 of heat deposits Ru 2 O 3 + 3aq. Formiate of soda does not reduce 

 the metal, but only decolorizes the solution ; the same happens with 

 oxalic acid. Ferrocyanide of potassium at first decolorizes the solu- 

 tion, which subsequently becomes green. Percyanide of mercury 

 colours the solution blue, with formation of a blue precipitate. 

 Nitrate of silver yields a black precipitate, which subsequently turns 

 white, while the liquid becomes rose-red. Chloride of potassium 

 and chloride of ammonium produce dark brown crystalline precipi- 

 tates only in very concentrated solutions. Sulphurous acid decolo- 

 rizes the sesquichloride only after long-continued action. Sulphu- 

 retted hydrogen produces the above-mentioned blue reaction, with 

 deposition of sulphuret. Sulphuret of ammonium throws down most 

 of the ruthenium from the solution as a blackish-brown sulphuret, 

 which is not perceptibly soluble in an excess of the precipitant. 



III. Perchloride of Ruthenium, RuCl 2 . — This compound is not 

 known in the isolated state ; it exists however in combination with 

 chloride of potassium. In the double salt described below it has the 

 rose colour of the salts of the perchloride of rhodium (Rh 2 Cl 3 ). 



Double Salts. 



I. Sesquichloride of Ruthenium and Potassium, 2KC1 + Ru 2 Cl 3 . 

 — From the composition of this salt the atomic weight of ruthenium 

 was ascertained, and found to be identical with that of rhodium. 

 The analyses of the other compounds of ruthenium have fully con- 

 firmed this determination. In the crystallized state it is perfectly 

 insoluble in alcohol of 0*863 spec, grav., and possesses in this respect 

 the properties of the double chlorides of all the other platinum 

 metals with potassium and ammonium. When however the salt is 

 in a concentrated solution, alcohol only throws down a portion ; 

 when the solution of the salt is mixed with the chloride of any other 

 metal soluble in alcohol, evaporated to dryness, and digested with 

 strong spirit, the salt of ruthenium dissolves in proportion to the 

 quantity of the other soluble chloride. This property is likewise 



