428 NITRIC ETHERS PROPERLY SO CALLED. 



6. NITROMANNITE : C 6 H 2 (N0 3 H) 6 . 



1. Equivalent, 452. 



2. Composition 



C ... = 159 



H = 18 



N = 186 



= 637 



1000 



The body crystallises in fine white needles. It must be 

 carefully purified by being re-crystallised in alcohol to free it 

 from -the products of incomplete nitrification. 



3. Its apparent density is 1'60, but by melting it under 

 pressure as much as 1/80 may be observed at 20. 



4. It melts between 112 and 113, and solidifies at 93. 

 The temperature of the melting point given by various authors 



falls to 70, but this is for an impure product 



5. Mtromannite commences to give off acid vapours from the 

 melting temperature. But this emission is very slow ; it is 

 accelerated with the rise in temperature. When suddenly 

 heated to about 190 it takes fire ; towards 225 it deflagrates, 

 towards 310 it explodes. 



When the heating has been progressive, and accompanied by 

 a commencement of decomposition, which alters the composition 

 of the residuum, inflammation and explosion can no longer take 

 place. 



6. Mtromannite purified by crystallisation in alcohol and 

 kept protected from sunlight can be kept for several years 

 without alteration, 



But if care be not taken to re-crystallise it, it contains much 

 more changeable products, which cause its progressive decom- 

 position. These products also lower its melting point to 

 about 70. 



7. Nitromannite explodes by the shock of iron on iron more 

 readily than nitroglycerin, but with rather more difficulty than 

 mercury fulminate. It is intermediate in its shattering pro- 

 perties. It explodes by the shock of copper on iron or copper, 

 and even of porcelain on porcelain, provided the latter shock 

 be violent. 



8. The heat of formation of nitromannite from the elements 

 has been found (p. 283), + 1561 Cal., according to a calculation 

 founded on the heats of formation of mannite, nitric acid, and 

 nitromannite, or -f 161*4 according to the heat of combustion 

 observed by Sarrau and Vieille. 



9. The heat of total combustion coincides with the heat of 

 decomposition (see p. 283). It is equal to + 683'9 Cal. at con- 



