WHICH NITROGEN IS SUBSTITUTED FOR HYDROGEN. 
727 
Calculated. Found. 
4H 2 0 . . . . 8 ; 08 8-00 
If the ammonium-salt of tetrasulphophenylenic acid be, instead of chloride of barium, 
treated with baryta-water, another barium-salt is formed, which, according to the sub- 
joined barium-determination, has the composition G 12 H 6 , S 4 Ba 6 0 15 . It is precipitated 
as a white amorphous powder, which, on washing with water, is converted into small 
prisms. 
0-6085 grm., dried at 150°, gave 0-4585 grm. of sulphate of barium. 
■Gi 2 H g , S 4 Ba 6 0 15 . 
Calculated. Found. 
Ba . . . . 44-24 44-29 
Silver-salt , 0 12 H 6 , S 4 H 3 Ag 3 0 15 . 
On mixing a concentrated solution of the ammonium-salt with an equally concen- 
trated solution of nitrate of silver, separation of warty crystals of this salt takes place 
after some time. They may be purified by recrystallization from water, in which they 
are easily soluble. The concentration of their solution must be conducted in vacuo. 
0-3955 grm., dried at 150°, gave 0-2025 grm. of chloride of silver. 
€12 H 9 S 4 Ag 3 -G 15 . 
Calculated. Found. 
Ag . . . . 38-34 38-50 
0- 4205 grm. of silver-salt, dried over sulphuric acid, lost at 150° 0-025 grm. of water. 
€ 12 H 9 S 4 Ag 3 0 15 +3H 2 0. 
Calculated. Found. 
3H 2 0 . . . . 6-00 5-95 
When describing disulphophenylenic acid (page 687), it was shown that it is capable 
of forming two series of salts exhibiting an analogous relationship to each other, as 
metaphosphates to ordinary phosphates. Tetrasulphodiphenylenic acid behaves in a 
similar manner. Thus the salts previously described point most naturally to the con- 
clusion that it is hexabasic, while the salts which will be presently mentioned indicate 
its capability of assuming also an octabasic character. 
Lead-salt , € 12 Hg, £4 Pb 8 C 16 . 
When a boiling solution of tetrazodiphenylenate of ammonium is mixed with a solu- 
tion of neutral acetate of lead, this salt is precipitated in the form of white needles. 
Repeated washings with water render it quite pure. 
1- 0195 grm., dried at 150°, gave 0-3797 grm. of carbonic acid and 0*054 grm. of water. 
