Intelligence and Miscellaneous Articles. 245 



"B 



of soda, is obtained by different processes ; either by treating oxide 

 of uranium by phosphoric acid, or acetate of uranium with this acid ; 

 or lastly, by precipitating nitrate of uranium by diphosphate of soda. 

 The salts obtained by these different processes do not, however, 

 contain the same quantity of water. They are of a bright yellow 

 colour, and usually crystalline, at least when seen by the microscope ; 

 they are insoluble in water and acetic acid, but soluble in the mineral 

 acids and excess of carbonate of ammonia. 



a. The salt obtained by treating oxide of uranium with dilute 

 phosphoric acid and submitted to washing, is not crystalline, becomes 

 deeper coloured by calcination, and on cooling reassumes its bright 

 colour. Analysis gave, — oxide of uranium, 72 - 77to 72'16; phosphoric 

 acid, 18-11 to 17*96 ; water between 248° and 356° F., 7*03; and 

 by calcination, 9" 12 to 9' 7 per cent. The formula deduced is 

 [P* O 5 , 2U 2 O- O, H- + 3 aq] . The calcined salt, moistened with 

 water and dried over sulphuric acid, regains 7 per cent, of water, 

 which may be expelled at 347° F. 



b. The salt obtained by adding phosphoric acid to a solution of 

 acetate of uranium, as long as a precipitate is formed, constitutes, 

 after washing, a crystalline powder, a little deeper than the foregoing 

 salt. Dried at 140° F. it yielded, — oxide of uranium, 67*93 ; water 

 at 248°, 12-9 per cent. ; and from 500° to calcination 15*74 to 15*2. 

 The calcined salt gave 80*1 of oxide of uranium and 19*9 of phos- 

 phoric acid. In another experiment, in which the salt had been 

 dried merely by exposure to the air, by heating to 248° F. it lost 

 2*19 per cent, of water, the same quantity at 320°, and by calcination 

 such a further quantity as to give 18*46 as the whole quantity of 

 water; the same salt gave 64*78 of oxide of uranium. From these 

 numbers M. Werther deduces the formula 



[P 2 O 5 , 2U 2 O* O, H20+ 8 aq] . 



c. The salt obtained by the mixture of diphosphate of soda and 

 nitrate of uranium has the same appearance as the foregoing ; it lost 

 12 91 per cent, of water at 248° F., and by calcination 15*08 ; it gave 

 67*97 per cent, of oxide of uranium, and 16*51 of phosphoric acid. 

 M. Werther obtained the same salt by precipitating incompletely the 

 trisphosphate of soda by nitrate of uranium, separating the precipi- 

 tate by a filter, and adding excess of nitrate of uranium to the filtered 

 liquid. 



When to nitrate of uranium an excess of trisphosphate of soda is 

 added, a deep yellow salt is precipitated, which redissolves almost 

 entirely on a further addition of the phosphate. If this excess be 

 avoided, and the precipitate be perfectly washed, an agglomerated 

 powder of a deep yellow colour is obtained, which, like all the other 

 phosphates, is insoluble in water, but which is decomposed by acetic 

 acid. This salt contains more uranium than the preceding ; the 

 author was, however, unable to obtain it of a composition exactly 

 corresponding to a trismetallic phosphate. — Journ. de Ph. et de Ch., 

 Juillet 1848. 



