140 



FLUORESCENCE OF THE URANYL SALTS. 



to the monoclinic crystal systems, the first to the trigonal and the third 

 to the rhombic system. Since all four spectra vary slightly in their 

 frequency intervals, the relative positions would change slightly if we 

 compared homologous groups in the other end of the spectrum, but 

 this gradual and slight shifting would not change the general condition, 

 which indicates that the absolute position of a group is largely deter- 

 mined by the crystal system. This is not entirely new, as the four 

 triclinic crystals of the double uranyl chlorides exhibit spectra which 

 are as nearly coincident as could be expected of salts which vary in 

 molecular weight. 



TABLE 50. Average intervals. 



Mono-ammonium uranyl nitrate. 



Fluorescence series . 



Absorption seiies 



Ratio of fluorescence to absorption . 



A 



86.6 



a 

 73.7 



1.18 



D 



88.3 



d 

 74.5 



1.19 



G 



87.7 



g 



74.2 



1.18 



I 



88.1 



i 

 75.1 



1.18 



Di-ammonium uranyl nitrate. 



Fluorescence series 



Absorption series. 



Ratio of fluorescence to absorp- 

 tion . . 



A 



84.4 



a 

 69.2 



1.22 



B 



84.4 



b 

 71.6 



1.18 



C 



84.3 



c 

 69.8 



1.21 



D 



84.5 



d 

 68.9 



1.23 



E 

 85.0 



e 

 68.7 



1.22 



G 



83.7 



a 



68.8 

 1.22 



I 



83.9 



i 

 69.6 



1.21 



J 



83.8 



3 



69.7 



1.20 



K 



84.8 



k 



70.9 



1.20 



L 



84.0 



I 



71.5 



1.18 



Mono-potassium uranyl nitrate. 



Fluorescence series. 



Absorption series 



Ratio of fluorescence to absorption. 



D 



86.9 



d 

 73.2 



1.18 



I 

 87.2 



i 

 71.9 



1.16 



K 



86.6 



fc 

 74.1 



1.17 



Di-potassium uranyl nitrate. 



Fluorescence series . 



Absorption series 



Ratio of fluorescence to absorption . 



D 



86.6 



d 

 72.7 



1.19 



E 



86.2 



e 

 74.8 



1.16 



F 



87.2 



75.0 

 1.16 



H 



86.5 



h 

 71.7 



1.21 



K 



86.9 



k 

 71.3 



1.22 



L 



86.9 



I 

 74.9 



1.16 



