218 Dr. Holzmann on some Cerium Compounds. 



stirring, .the crystalline powder may easily be separated from the 

 mother-liquor. The salt is perfectly colourless, very soluble in 

 water and alcohol, and exceedingly deliquescent in moist air. 



(1) 0*5585 grm., three times recrystallized from water and 

 dried over caustic lime and chloride of calcium, gave, after eva- 

 poration with hydrochloric acid and bichloride of platinum 

 and ignition of the ammonio-chloride of platinum, 0*1485 Pt. 

 After treating the filtrate with sulphuretted hydrogen and preci- 

 pitating it with oxalate of ammonium, 0*1702 Ce 3 4 were left 

 on the ignition of the oxalate of cerium. 



(2) 0*4325 grm., treated in the same way, gave 0*112 Pt. 



(3) 0*3138 grm., precipitated with oxalate of ammonium, gave 

 00977 Ce 3 4 . 



(4) 0*5905 grm. gave, after Dumas's method, 74'44 cubic 

 centims. nitrogen of 0° C, and 760 millims. pressure. 



These numbers are represented by the formula 



2(CeO, NO 5 ) + NH 4 0, N0 5 4-8HO. 



Theory. 



Experiment. 



--, (1) (2) (3) (4) 



2CeO . . 108 29-35 2904 2967 



NH<0 . . 26 7061 N31 , 22 698 680 *).,_ 



3NO* . . 162 44-02 } N152J J 1584 



8HO . . _72 19-57 

 368 10000 



In addition to the double salts of the nitrate of jjroto-sesquioxide 

 of cerium, formerly described, I have prepared the ammonium-salt, 

 which corresponds in composition and properties to the potas- 

 sium-salt. 



A mixture of the solutions of the two salts crystallizes, when 

 left over caustic lime and chloride of calcium, in orange-red cry- 

 stals, which have the appearance, under the microscope, of hexa- 

 gonal prisms ; this double salt is exceedingly deliquescent. The 

 salt, recrystallized several times from water and dried over lime 

 and chloride of calcium, gave on analysis the following results : — 



(1) 0*4285 grm., treated as the ammonium double salt of the 

 protoxide of cerium, gave 0*1477 Pt, and 0*1265 Ce 3 4 , 



(2) 0*5442 grm., treated in the same manner, gave 0*1832 

 Pt, and 0*16 Ce 3 4 . 



(3) 0*4645 grm., ignited alone, gave 0*1385 Ce 3 4 . 



(4) 0*5684 grm. gave, after Dumas's method, 91*52 cubic 

 centims. N of 0° C, and 760 millims. pressure. 



(5) 0*5633 grm., dissolved in water and precipitated with 

 oxalate of ammonium, gave 0*1658 Ce 3 4 . 



I thought it superfluous to determine the degree of oxidation 

 of the cerium, as the values obtained agree exactly with the 



