URANIUM SALTS. 



93 



Uranyl Chloride in Methyl Alcohol. 



The first spectrogram for mapping out the absorption spectrum of 

 uranyl chloride in methyl alcohol is given in Plate 53, B. Exposures 

 were made to the Nernst glower for 1 minute with a slit-width of 0.08 mm. 

 and a current of 0.8 ampere. The depth of cell is 6 mm. for each strip. 

 Beginning with the strip nearest the numbered scale, the concentrations 

 are 0.0625, 0.079, 0.1, 0.125, 0.158, 0.2, and 0.25 normal. 



The alcoholic solution of uranyl chloride is veiy similar to the alcoholic 

 solution of uranyl nitrate, the absorbing power of both solutions being 

 considerably greater than that of aqueous solutions. The aqueous solution 

 of uranyl chloride shows only a few of the characteristic uranyl bands in 

 its absorption spectrum. In the alcoholic solution, however, they appear 

 very strongly. 



Starting with the most concentrated solution, whose absorption spec- 

 trum is given by the strip furthest from the numbered scale, we have the 

 bands a and b appearing and all wave-lengths less than X 4500 completely 

 absorbed. The b band is very strong, the a band very weak almost 

 lost in this region of the spectrum where the film is less sensitive to the 

 light. For the next concentration, 2 normal, we have a weak transmis- 

 sion band appearing in the ultra-violet. Other uranyl bands appear as 

 the concentration is decreased. We shall now consider the blue-violet 

 band. For the 0.2 normal solution its limits are XX 4450 and 3800, for 

 the 0.158 normal solution XX 4400 and 3900, and for the 0.125 normal 

 solution XX 4350 and 3900. The middle of the band would thus come at 

 about X 4100. 



The uranyl bands a, b, c, d, e, f, g, h, i, and / all appear. The bands 

 b and c are the largest and strongest. Band a is relatively much weaker. 

 The appearance of the bands is somewhat like the bands of uranyl nitrate 

 in methyl alcohol. The uranyl nitrate bands are, on the whole, considerably 

 fainter and narrower than the uranyl chloride bands. Bands a, b, and c 

 are almost of the same intensity in the case of the nitrate, all being quite 

 faint. The blue-violet band is much more diffuse in the spectrum of the 

 uranyl nitrate. The following are the wave-lengths of the bands of uranyl 

 chloride, the second row giving the wave-lengths of the same bands for 

 uranyl nitrate in methyl alcohol: 



The a, b, and c bands of the chloride and nitrate come at about the 

 same positions, but the e, f, g, and h bands of the chloride are all shifted 

 towards the red as compared with the same bands of the nitrate. The 

 uranyl chloride bands in water are slightly shifted towards the violet with 

 reference to the uranyl chloride bands in methyl alcohol. 



