642 URANIUM. 



Many of the metallic antimoniates, particularly those of cobalt 

 and copper, lose first their combined water when heated, and 

 afterwards glow strongly when heated to redness. After that 

 change, these antimoniates are not soluble either in acids or 

 alkalies. 



Sulphantimonic acid, Sb S 5 , is obtained when antimonic acid 

 or the following chloride of antimony is precipitated by sul- 

 phuretted hydrogen. It is of a much paler red colour than the 

 other sulphurets of antimony, and constitutes the golden sul- 

 phuret of antimony of several pharmacopeias. 



Pentachloride of antimony, Sb C1 5 , is formed when metallic 

 antimony in powder is gently heated in chlorine gas. The an- 

 timony burns with scintillations, and a colourless or slightly 

 yellow coloured liquid distils over. This chloride condenses 

 olefiant gas as readily as chlorine, and forms the Dutch liquid, 

 the pentachloride being reduced at the same time to terchloride 

 of antimony. 



ORDER V. 



METALS NOT INCLUDED IN THE FOREGOING CLASSES, OF WHICH 

 THE OXIDES ARE NOT REDUCED BY HEAT ALONE. 



URANIUM. LANTANUM. 



CERIUM. TANTALUM. 



URANIUM. 



Eg. 2711.4 or 217.26; U. 



This metal is derived from the mineral pitchblende, which con- 

 sists principally of protoxide of uranium. The mineral is dis- 

 solved in aqua regia, and a stream of sulphuretted hydrogen 

 passed through the liquor, by which copper, lead and arsenic are 

 precipitated. The liquid is afterwards boiled, and the protoxide 

 of iron peroxidised by means of nitric acid. An excess of am- 

 monia is then added to the liquid, and the precipitate formed of 

 oxides of uranium, iron, cobalt and zinc, is washed, then 

 treated with a dilute solution of carbonate of ammonia, which 

 leaves the peroxide of iron, and dissolves the other oxides. 

 By boiling the yellow solution, the carbonate of ammonia is ex- 

 pelled, and the oxides precipitate. These are dried and ignited, 

 by which protoxide of uranium is rendered insoluble in acids. 



