82 THE ABSORPTION SPECTRA OF SOLUTIONS. 



strips). The temperatures are 20, 45, 85, 20, 50, and 95 C. The methyl 

 ester at 20 showed very strong bands at XX 4600, 4760, and 4930. 



It was thought that by adding a large amount of a salt like calcium 

 chloride to solutions of uranyl chloride in different solvents the absorption 

 spectra of the resultant solutions would be more alike. The spectrogram 

 shows that this is not the case, since it will be seen in the lower strips that the 

 uranyl bands are very strong and quite sharp, whereas in the case of the 

 methyl alcohol solution the bands are very wide and very weak. Their wave- 

 lengths are also considerably greater than those of the bands in the ester solu- 

 tion. These spectrograms show that although double salt aggregates may 

 be formed, the solvent part of the aggregate still plays a very important role 

 in influencing the wave-lengths of the absorption bands. 



The effect of the addition of calcium chloride to the ester solution was 

 not tested by regular steps, but for the pure uranyl chloride solution the a 

 band appears as a double band with the components at about X 4930 and 

 X 4965. These bands practically merge into one another, and it is rather 

 difficult to see that the band is really double. Apparently the effect of the 

 addition of calcium chloride is to cause the component X 4965 to disappear, 

 and, at the same time, the other component widens. The methyl ester solu- 

 tions offer a promising field for studying the spectrophotography of chemical 

 reactions and also for the effect of dilution. 



A, plate 64, represents the absorption of 0.005 normal solution of uranyl 

 chloride in methyl ester, the depth of cell being 10 cm. The temperatures, 

 starting with the lowest strip, are 20, 45, 70, 90, 110, 135, and 140 C. 



At 20 the following uranyl bands appear: X 3930 fine and weak; X 4050 

 quite narrow; X 4170, X 4300, X 4450, X 4630, and X 4800 probably the b band. 

 At 140 C. only the b, c, and d bands appear at XX 4480, 4650, and 4820. At 

 the highest temperature the transparency of the solution in the violet has 

 apparently increased. The character of the uranyl bands is but slightly 

 affected by the above temperature changes. 



Uranous Chloride in Water and Methyl Alcohol. 



Strip 5, A, plate 67, represents the absorption of uranous chloride in a 

 mixture of water and methyl alcohol, in such proportions that the water and 

 alcohol bands were of about equal intensity at 10 C. Strip 6 represents the 

 same solution at about 70 C. 



These strips show that at the higher temperature the uranous water 

 bands have almost disappeared. The uranyl bands have also become very 

 much weaker, and the uranous alcohol bands slightly weaker. No appreciable 

 shifting of the bands is to be noticed. 



Uranous Chloride in Acetone. 



A spectrogram of the absorption spectrum of uranous chloride in acetone 

 was taken at 20, 40, 65, 80, 95, and 105. 



At about 60 a precipitate was formed, and above this temperature the 

 red absorption band hardly appears at all. The uranous bands in the green 

 and yellow seem to be considerably stronger after the formation of the pre- 

 cipitate. 



