40 THE ABSORPTION SPECTRA OF SOLUTIONS. 



Neody.mil m Acetate in Acetone. 



The absorption spectrum of neodymium chloride in acetone has bands 

 that are much more diffuse than the corresponding water bands. Similarly, 

 the acetone bands of the acetate are more diffuse than the water bands, and 

 both spectra are more diffuse than the chloride spectra. 



The a group of the acetate in acetone apparently consists of but a single 

 band, quite weak, at X 4270 and about 15 Angstrom units wide. The region 

 X 4300 to X 5100 is practically continuous, the bands appearing there being 

 so weak and diffuse that they can hardly be detected. The <5 group consists 

 of a wide diffuse band at X 5110 and finer bands at X 5200 (weak), X 5235, 

 X 5250, and X 5260; the latter three practically blending into one. The e group 

 extended from X 5J720 to X 5860, this absorption showing a weak band at 

 X 5730, about 30 Angstrom units in width. From the above description it 

 will be noticed that there is a strong ultra-violet absorption (reaching to 

 X 3900), and that the neodymium bands themselves are very wide and diffuse. 



Neodymium Acetate in Formamide. 



A, plate 13, represents the absorption spectrum of neodymium acetate in 

 a formamide solution. The absorption bands of this solution are quite wide 

 and diffuse, but not as much so as the bands of the acetate in acetone. The 

 ultra-violet absorption is so strong as to prevent the appearance of the a group. 

 The /3 group consists of a band at X 4285, which is about 10 Angstrom units 

 wide. The bands XX 4440, 4690, 4750, 5110, and 5230 are wide, diffuse, and 

 with the exception of the latter, are all very weak. The e group consists of 

 four diffuse bands that run into each other at XX 5710, 5740, 5790, and 5830. 



Summary of Neodymium Spectra. 



a Group in Water. Neodymium chloride in water gives X 3390 a very 

 weak band, X 3465 narrow and strong, X 3505, X 3540 narrow and strong, and 

 X 3560. The anhydrous chloride gives a rather strong and narrow band at 

 X 3500, a weaker band at X 3537, narrow and intense bands at X 3570 and 

 X 3595, and a rather hazy band at X 3612. 



a Group in Methyl and Ethyl Alcohols. The chloride shows the bands 

 XX 3475, 3505, and 3560. These bands are much hazier than the water bands. 

 The latter one is by far the most intense. The nitrate in methyl alcohol has 

 two bands, X 3465 and X 3545. 



a Group in Acetone. The nitrate has rather faint and wide bands at 

 X 3475 and X 3555. 



a Group in Glycerol. The chloride gives a weak band at X 3520, and 

 strong and sharp bands at X 3475 and X 3550. 



/3 Group in Water. Neodymium chloride in water gives a very sharp 

 band at X 4271, and a very narrow and weak band at X 4290. The anhydrous 

 salt gives narrow and intense bands at X 4308 and X 4313, a wider band at 

 X 4333 and a narrow band at X 4357. Neodymium nitrate in water has a band 

 at about X 4280, which is more hazy than the X 4271 chloride band, and which 

 breaks up into a band :it X 4271 and a sort of shading on the red side of this 

 band at about X 4280. 



o /3 Group in Methyl and Ethyl Alcohols. A band appears at X 4290 about 

 10 Angstrom units wide. This is wider and fainter than the water band at 



