222 FLUORESCENCE OF THE URANYL SALTS. 



a fine crystalline mass which was very fluorescent. The spectrum of this was 

 studied. The potassium, ammonium, lithium, and calcium salts were also 

 prepared and seen to have characteristic line spectra, but were not studied 

 further. The mineral autunite is a basic calcium uranyl phosphate which 

 Stokes 1 says shows brilliant fluorescence, while chalcolite, the analagous copper 

 compound, has none, but shows the same absorption bands characteristic 

 of uranyl compounds. 



CHROMATES. 



An attempt was made to prepare the sodium uranyl chromate described by 

 Rimbach, which resulted in a brown mass. The uranyl chromate UO 2 CrO 4 - 

 3H20 (Orloff) 2 from TJ0 3 and Cr0 3 gave yellow needles with no fluorescence. 

 The potassium salt from K 2 Cr 2 7 and UO 3 was also without fluoresecence. 



FLUORIDES. 



Cragwall prepared the uranous and uranyl fluoride fromUsOgand HF, which 

 showed practically no fluorescence. He also prepared the double potassium 

 salt K 3 U0 2 F 5 by adding KF to uranyl nitrate and (NH 4 ) 3 U0 2 F 5 by dissolving 

 (NH 4 ) 2 U 2 07 in HF. 3 The double salts showed characteristic spectra, but the 

 fluorescence was very weak. 



URANYL IODATE. 



This salt was prepared from sodium iodate and uranyl nitrate by Cragwall 

 by a method which, according to Artmann, 4 would result in U0 2 (I0 3 ) 2 H 2 of 

 the rhombic form. This showed little fluorescence. 



MISCELLANEOUS INORGANIC COMPOUNDS. 



An attempt was made to produce bromides and iodides analogous to the 

 chloride salts without results, due to decomposition with the liberation of 

 bromine and iodine. An attempt was also made to produce molybdyl and 

 tungstyl ammonium chloride double salts analogous to the uranyl salts by 

 heating the oxides with ammonium chloride and hydrochloric acid in sealed 

 tubes, which in some cases resulted in crystals, which, however, showed no 

 fluorescence. Uranic acid or H 2 UO4 was also sealed up in tubes with anhy- 

 drous liquid NH 3 , C0 2 , S0 2 , and HC1. None of the resulting compounds 

 were soluble or fluorescent, although changes took place, the carbonate being 

 nearly white, the sulphur-dioxide tube greenish, due to reduction, and the 

 ammonia tube reddish like the diuranate. 



Of the uranates, the sodium potassium calcium and barium were made, none 

 of which showed fluorescence, the first two being golden yellow plates, the 

 latter two an amorphous greenish mass. 



URANYL ACETATES. 



The anhydrous uranyl acetate U0 2 (C 2 H 3 2 )2 was. prepared by Cragwall 

 according to Spath 5 by adding acetic anhydride to uranic oxide. This latter 

 took up some water and became partially the dihydrate. On recrystallizing 

 some of the material from acetic-acid solution, small clear cubes were obtained 

 which appeared to contain acetic acid of crystallization. 



1 Stokes, Phil. Trans. Roy. Soc. London, 142, 518. 1852. 



2 Orloff, Chem. Ztg., 31, 375. 1907. 



3 H. F. Baker, Chem. Soc. Jour., 35, 763-769. 1879. 



4 Artmann, Z. Anorg. Chem., 79, 327, 1913. 

 6 Spath, Monatsh. J. Ch. 33, 248. 1912. 



