Chemical Notices : — M. Popp on Yttria. 375 



relation of the sulphuric acid to the yttria found, Popp deduces the 

 number 42 as the combining proportion of yttria, which, assum- 

 ing that it has the composition YO, gives 34 for the combining 

 proportion of yttrium. 



The metal yttrium was reduced from the chloride of ammo- 

 nium and yttrium by means of sodium, in a manner analogous 

 to that by which magnesium is prepared. While moist it is a 

 black glittering powder, which, while drying, becomes lighter, 

 owing to oxidation. When quite dry it does not oxidize in the 

 air ; at ordinary temperatures it only slowly oxidizes in water ; 

 on boiling, the oxidation is more rapid, but even then is not 

 complete. It is readily dissolved by dilute acids with disen- 

 gagement of hydrogen. 



Heated on platinum foil, yttrium burns with intense lustre; 

 in pure oxygen the combustion is most brilliant ; the colour is 

 not of such a pure white as is that of magnesium and alumi- 

 nium; it inclines towards reddish. 



By the properties of the metal, as well as those of its com- 

 pounds, yttrium is allied to magnesium ; and by its property 

 of being precipitated by ammonia it is the connecting link 

 between the alkaline earths and the earths proper. Some of the 

 best-defined and most important of its salts are the following. 



The sulphide of yttrium is difficult to prepare. The best results 

 are obtained by passing dry bisulphide-of-caibon vapour mixed with 

 dry hydrogen over heated yttria. Chloride of yttrium, YC1 + 6 HO, 

 crystallizes in rhombic very deliquescent plates. Chloride of 

 yttrium is non-volatile and a chloro-base ; it forms with chloride 

 of mercury easily soluble deliquescent crystals, which have the 

 formula YCl,2HgCl + 6HO. Sulphate of yttria ,ZYO SO 3 + 5 HO, 

 has the peculiarity that its solubility diminishes proportionally 

 to the increase of temperature. At 30° to 40° its solution 

 becomes turbid, and on boiling, all the salt separates out as a 

 heavy crystalline powder. Nitrate of yttria, dissolved in alcohol 

 and evaporated over alcohol, forms well-defined rhombic plates, 

 which are deliquescent and have the composition YO N0 5 + 3HO. 

 Carbonate of yttria, YO CO 2 -f 3 HO, is obtained, by precipitating 

 a solution of yttrium with carbonate of sodium, as a gelatinous 

 precipitate, which, digested with an excess of carbonate of soda, 

 is converted into small white crystalline needles. The acetate of 

 yttria is the most easily crystallizable of all the salts ; it has the 

 composition YOAc + 2HO. 



Redtenbacher has described to the Vienna Academy of Sciences* 

 an improved method of separating the metals potassium, rubidium, 



* Bulletin, No. 8. 1865. 



