466 PICRIC ACIDS AND PICRATES. 



Hence it will be seen that " chlorated " picrate does not bear 

 out, by an exceptional strength, the hopes which the vivacity 

 of its explosion had given rise to at the outset. It therefore 

 does not compensate in this direction for the considerable 

 dangers which result from its great sensitiveness to shock, 

 friction, and inflammation, as well as the easy propagation of 

 the latter by dust trails. Its use, therefore, seems to be almost 

 abandoned. 



6. AMMONIUM PICRATE. 



1. This is an orange-yellow salt, in needles, less hard than 

 potassium picrate. It is far less sensitive to shock. Ignited in 

 the open air it burns like a resin, with a smoky flame. It has 

 been used in pyrotechny as a fusing substance. However, 

 when burnt at a high density of charge, or in a confined space, 

 from which the gases only escape by a small orifice, its com- 

 bustion may change into detonation. 



2. Its formula is 



C,H 2 (NH 4 )(N0 2 ) 3 0; 

 its equivalent, 246. 



3. Its heat of formation from the elements 



C 6 + H 6 + N 4 + 7 = C 6 H 6 N 4 7 , 



is equal to -f 801 Cal. ; or, for 1 kgm., 326 Cal. 



4. Its total combustion needs an excess of oxygen 



C 6 H 6 T 4 7 -f 8 = 6C0 2 -f 3H 2 + 2N 2 , 



and liberates + 690*4 Cal. (liquid water), or -f 6604 Cal. 

 (gaseous water). 



5. The equation of the explosive decomposition has not been 

 studied. 



6. Only the combustion by a combustive agent, such as 

 potassium nitrate, will be examined 



5C 6 H 6 T 4 7 + 16KN"0 3 = 8K 2 C0 3 + 22C0 2 + 15H 2 + 36N, 

 or 



16KHC0 3 -f 14C0 2 + 7H 2 + 36N 

 after cooling. 



The total weight is here 569*5 grms. per 1 kgm.; viz., 568 

 grms. of saltpetre and 432 grms. of picrate. 



The heat liberated by the combustion of " nitrated " ammo- 

 nium picrate amounts to + 701 Cal. (liquid water, bicarbonate), 

 or to -f 631-5 Cal. (gaseous water) ; or, per 1 kgm., 1231 Cal., or 



7. The reduced volume of the gases = 245 -5 litres (gaseous 

 water), or 174 litres (liquid water, bicarbonate), which makes 

 per 1 kgm. 431 litres, or 305 litres. 



