1911] 



on New Oryaiik Compoaiuh of Nitrogen. 



155 



the alkali metals may be handled without risk. The latest recruit to 

 the metallic azoimides is radium azide, described by Ebler about six 

 months ago, and utilized in attempts to prepare metallic radium, 

 which appears to follow the decomposition of radium azide by heat, 

 just as barium azide may be shown to yield the metal when deprived 

 of nitrogen. Pursuing the analogy between the triazo-group and the 

 halogen atoms, a study of the refrangibility and dispersion of light 

 by organic triazo-conipounds deserves attention. The following 

 measurements have been carried out by Philip, and show that while 

 the mean increment of refraction for an atom of bromine is .S-9;^>, 

 that of the triazo-group is 8 "91, and whilst the atomic dispersion of 

 bromine is (V35, the increment traceable to the azoimide nucleus 

 is • 36. 



Contribution of Na-Group to 



Ethyl Triazoacetate .... 

 Ethyl o-Triazopropionate . 

 Ethyl ^-Triazopropionate . 

 Ethyl Bistriazoacetate . 

 Triazoethyl Alcohol .... 



Bistriazoethane 



Benzylazoimide 



Contribution of N3 (mean) 

 Contribution of Br . 



Moreover, on comparing the temperatures at which a number 

 of typical triazo-compounds boil with the constants for halogen 

 derivatives having similar structure, it appears that the triazo-group 

 exerts an elevating effect considerably greater than that of chlorine, 

 somewhat greater than that of bromine, and approximating to that 

 of iodine. Furthermore, it has been shown by Philip that the intro- 

 duction of a triazo-group into a molecule of acetic acid has an effect 

 on the strength of the acid which is rather less than that due to a 

 bromine atom and rather greater than that caused by an iodine atom. 



