WHICH NITROGEN IS SUBSTITUTED FOR HYDROGEN. 
685 
almost insoluble in alcohol and ether. The solutions have a neutral reaction. The 
substance was dried at 160° C. ; and on analysis 
0-4587 grm. gave 0-3067 grm. of carbonic acid and 0-0649 grm. of water. 
0-4505 grm., precipitated with sulphuric acid, gave 0-2495 grm. of sulphate of barium. 
0-321 grm., analyzed by Cakius’s method, gave 0*379 grm. of sulphate of barium*. 
These numbers lead to the formula 
€ 6 H 6 Ba 2 S 2 0 8 . 
Theory. 
Experiment. 
r~' 
72 
17-70 
18-23 
h 6 
6 
1-47 
1-55 
Ba 2 
137 
33-66 
33-59 
64 
15-72 
16-21 
128 
31-45 
— 
407 
100-00 
The salt, dried over sulphuric acid, contained 3| atoms of water of crystallization, 
which escaped entirely at 130° C. No further loss of water was observed on heating 
to a higher temperature. 
I. 0-5435 grm. of substance, dried over sulphuric acid, and lastly at 130° C., lost 
0-0755 grm. of water. 
II. 0-5398 grm. was dried at 190° C. and lost 0-073 grm. of water. 
C 6 H 6 Ba 2 S 2 0 8 -j-3±H 2 O. 
Calculated. Found. 
t \ 
I. II. 
13*44 13-89 13*52 
In accordance with the analysis of the barium-salt, the free acid must be expressed 
by the formula G 6 H 8 -S 2 O g , and I propose to call it disulphophenylenic acid, since it 
may be viewed as a compound of two molecules of sulphuric acid, with the hypothetical 
hydrocarbon 0 6 H 4 (phenylene), viz. 0 6 H 4 -S 2 Ii 4 0 8 . Its formation may be thus ex- 
pressed : — 
foH 4 N 2 S H 2 04+SH, O 4 =0 6 H 4 S 2 H 4 0 8 +N 2 
Sulphate of diazohenzol. Disulphophenylenic acid. 
The free acid is easily prepared by dissolving the barium-salt in water, carefully pre- 
cipitating the barium with sulphuric acid, and concentrating the filtrate on a water-bath 
till it acquires a syrupy consistency ; when it is placed over sulphuric acid, it crystallizes 
out in the form of warty crystals, which are exceedingly soluble in water and alcohol, 
and deliquesce in a moist atmosphere. 
* It is not even requisite to heat the substance with nitric acid in sealed glass tnbes ; for the sulphur in the 
substance is entirely converted into sulphuric acid by the action of concentrated nitric acid at the ordinary 
pressure. The acid is converted into a crystallized nitro-acid, resembling picric acid. 
4 t 2 
