204 



FLUORESCENCE OF THE URANYL SALTS. 



THE URANYL NITRATE IN ALCOHOL. 



The luminescence spectrum of the normal aqueous solution diluted 

 with ethyl alcohol is distinctly different from that of the aqeous solu- 

 tion. (See fig. 106.) The sharply resolved spectrum is quenched and 

 the new bands are not in the same positions. The unfrozen solutions in 

 a mixture of alcohol and water are not so opaque as the aqueous 

 solutions; hence it is necessary to freeze them to produce sufficient 

 absorption to bring out the luminescence. The first readings were 

 taken when the temperature was 90, and a consistent shift to the 

 violet was effected by further reduction in temperature. 



The spectrum of a solution of uranyl-nitrate crystals in ethyl alcohol 

 will also be found in figure 106. At -90, -120, and -150 slight 

 change in form or wave-length occurs, but at 185 fairly well resolved, 

 crests protrude above the crests of the broad bands, still existent. It 

 is probable that one series is due to the water of crystallization, the 

 other to the alcohol. Jones and Strong 1 have attributed the presence 

 of two sets of absorption bands in the water and alcohol solutions to 

 the presence of both a hydrate and an alcoholate, and the two lumines- 

 cence spectra are undoubtedly caused by such a combination. 



ENERGY IN CRESTS OF BANDS. NITRATE AT -90. 



6I80A 5870A 5586 A 5324A 5088A 4863 A 



FIG. 107. 



A solution of uranyl nitrate in methyl alcohol (fig. 106) presented 

 bands which in the manner of development with temperature resem- 

 bled the aqueous bands. The doublets fall into two series of constant 

 intervals. It will be observed in figure 106 that the bands of the alco- 

 holic solutions are in approximately the same positions. 



1 Loc. cit., p. 104. 



