570 Messrs. Jones and Strong on the Absorption 



/acetate. In the pure acetate solutions the a and b bands are 

 very weak. The c band, on the other hand, is quite the 

 strongest one of the series, the shorter bands gradually 

 decreasing in intensity. The addition of sulphuric acid does 

 not break up the acetate bands. On the other hand, the 

 addition of nitric acid apparently causes the g-h and the j-k 

 acetate bands to become a simple band. 



The addition of acetic acid to uranous chloride in water 

 causes the b, c, and d bands to double and the e, f, g, and h 

 bands to shift to the red. Sulphuric acid added to a nitric 

 acid solution of uranyl nitrate does not greatly affect the e 

 (X 4370) and / (X 4230) nitrate bands. The g nitrate band 

 disappears, however, and the 7i, i, and^ bands are each shifted 

 about 50 A.U. to the red. The k (X 3740) and I (X 3660) 

 bands are unaffected. In a spectrogram showing the ab- 

 sorption of uranyl nitrate in nitric acid to which sulphuric 

 acid is added, the d nitrate bnnd is gradually shifted about 

 70 A.U. to the red by the addition of sulphmic acid, until it 

 joins the c band which remains stationary. Nitric acid has 

 very little effect upon the uranyl bands of uranyl sulphate 

 in strong sulphuric acid. Sulphuric acid causes the uranous 

 and uranyl bands of an aqueous solution of a mixture of 

 uranium chloride and aluminium chloride to shift to the 

 violet. Hydrobromic acid, like sulphuric acid, does not 

 greatly modify the uranyl acetate bands. 



The addition of hydrochloric acid to a solution of uranyl 

 nitrate and nitric acid increases very greatly the ultra-violet 

 absorption. Even a drop or two of hydrochloric acid pro- 

 duces a very marked effect upon the uranyl bands. The a 

 band of the pure nitric acid solution is very weak and narrow. 

 Apparently it fades out and the a band of the chloride 

 becomes stronger and stronger. The b nitrate band does not 

 shift when hydrochloric acid is added, but a chloride band 

 farther to the red takes its place. The c nitrate band is very 

 slightly shifted. On the other hnnd, the b nitrate band is 

 shifted very greatly towards the red by the addition of 

 hydrochloric acid, and finally unites with the c band to form 

 a single broad band. The other nitrate bands are shifted to 

 the red when hydrochloric acid is added. 



A given uranous or a given uranyl salt often has different 

 absorption bands in different solvents. In some solvents the 

 differences are not great. For instance, the uranyl bands of 

 uranous chloride in glycerol and in methyl and ethyl alcohols 

 are very similar. In other cases the absorption spectra are 

 very dissimilar. Uranous chloride in acetone has the b band 





