WHICH NITROGEN IS SUBSTITUTED EOR HYDROGEN. 
731 
ether, and quite insoluble in water. It fuses at 148° C. to a yellowish oil, which can be 
distilled without decomposition. 
On heating in like manner the perhromide of tetrazodiphenyl with carbonate of 
sodium, a mixture of bromine and nitrogen gas is evolved, and on heating more strongly 
an oily substance distils over, which quickly solidifies. It is obtained pure for analysis 
by repeated recrystallization from ether. 
0-322 grm. gave 0-5513 grm. of carbonic acid and 0-082 grm. of water. 
These numbers correspond, as might be expected, with the formula 
^12 Hg Br 2 • 
Theory. 
Experiment. 
^12 
144 
46-15 
46-69 
Hg 
8 
2-57 
2-84 
Br 2 
160 
51-28 
— 
312 
100-00 
This compound, which may be called dibromodiphenyl, resembles the previously 
described chlorine-compound ; it crystallizes likewise in well-formed prisms, which appear 
to be even more insoluble in alcohol and ether than the above, and which fuse at 164° C. 
This substance is obtained, moreover, by boiling the perhromide with alcohol, as in the 
following equation : — 
£ 12 H b - N 4 H 2 Br 2 Br^ = € 12 H 8 Br^ + N 4 +Br 4 . 
Perhromide. Dibromodiphenyl. 
The substance separates from the alcoholic solution on cooling in crystals; it is best 
purified by distillation. 
Dr. Fittig informs me that he obtained a compound of like composition by acting 
with bromine upon diphenyl. The description of this new compound given by him 
applies so entirely to the dibromodiphenyl prepared by me, that no doubt remains of 
the identity of the bodies obtained by different methods. 
5 E 
MDCCCLXIV. 
