ii2 CHEMICAL PROPERTIES AND COMPOSITION 

 In diatomic glycol the quantity is just sufficient 

 H 2 CONO 2 H 3 CONO 2 = 2 CO 2 + 2 H 2 O. 



In glycerine the quantity is already slightly too little 

 and in gun cotton still more so, so that the highest point is 

 reached in glycol nitrate. 



Still better, on theoretical grounds, are suitably chosen 

 true nitro-compounds, containing the group 



C N^ 

 X) 



These have the advantage of the nitrates in possessing 

 oxygen in a strained position ; but also the carbon which, 

 in the former case, was partly combined with oxygen is 

 now combined with nitrogen, which, according to the data 

 for cyanogen, on p. 105, also implies a strain. If, again, 

 we choose the most suitable body, that in which the oxygen 

 is just sufficient for the carbon, we shall find it in dinitro- 

 acetylene, which is not at present known 



which has, moreover, the advantage of the endotherrnic 

 triple linkage. Somewhat less suitable, for these reasons, 

 is the equally unknown hexanitrobenzene, although here 

 again the oxygen is just sufficient for combustion of all the 

 carbon. Trinitrobenzene is again somewhat behind the 

 preceding 



, 



of the trinitrobenzenes, picric acid (1.3.5 C 6 H^(NO ) 3 ) is 

 used as an explosive under the names of lyddite and 

 melinite. It is of importance for that purpose, previously 

 to melt the solid substance in order to give it a suitable 

 inner structure and explosiveness. 



