WHICH NITROGEN IS SUBSTITUTED FOE HYDROGEN. 
721 
hexagonal plates. These crystals are almost insoluble in water, alcohol, and ether. 
Exposure to light during drying causes them to assume a slightly brown colour. 
0-6125 grm. gave 0-5252 grm. of carbonic acid and 0-0915 grm. of water. 
0-6065 grm. gave 44-1 cub. centims. of nitrogen at 0° C. and 760millims. bar. pres- 
sure, = 0-055415 grm. 
0'739 grm. gave on ignition with carbonate of soda 0-232 grm. of platinum. 
Calculated. 
Found. 
€12 
144 
23-29 
23-38 
h 8 
8 
1-30 
1-66 
n 4 
56 
9-05 
9-44 
Pt 2 
197-4 
31-92 
31-40 
Cl 4 
213 
34-44 
— 
618-4 
100-00 
Perbromide of Tetrazodiphenyl, G 12 H 6 N 4 , 2HBr, Br 4 . 
This compound is formed on the addition of bromine-water to an aqueous solution of 
the nitrate of the tetrazodiphenyl, being precipitated in the form of round reddish 
crystals, which are collected on a filter, thoroughly washed with water, and dried without 
delay over sulphuric acid and caustic lime. They are thus obtained sufficiently pure 
for analysis. Further purification indeed is impossible, since this body is decomposed 
by dissolving in alcohol, with evolution of gas. Even at the ordinary temperature it 
undergoes a gradual decomposition and evolves bromine, which is recognizable by its 
odour. For this reason the bromine-determinations, which were made with portions of 
this body that had been left for several days under the desiccator, were found a little too 
low. 
I. 0 - 583 grm., decomposed with alcoholic potash, gave 0-931 grm. of bromide of silver 
=67-96 per cent. 
II. 0-742 grm. gave, on ignition with caustic lime, 1-192 grm. of bromide of silver 
=68-36 per cent. 
€ 12 H 6 N 4 , 2HBr, Br 4 . 
Found. 
t ' A "i 
Calculated. I. II. 
Bromine 69-77 67-96 68-36 
f^ 2 H 6 N 4 l 
Tetrazodiphenyl-amidobenzol, J G 6 H 7 N >• 
hi H 7 N J 
By adding aniline to an aqueous solution of nitrate of tetrazodiphenyl, this complex 
substance, corresponding to the diazo-amidobenzol in the diazobenzol series, is at once 
separated as a yellow crystalline mass; by repeatedly washing with alcohol it is easily 
obtained in a pure state for analysis. 
