"WHICH NITROGEN" IS SUBSTITUTED EOR HYDROGEN. 
677 
Theory. 
X 
Experiment. 
72 
'31-44 
31-68 
H s 
5 
2-19 
2-40 
n 2 
28 
12-23 
— 
Ag 
108 
47-16 
46-46 
0 
16 
6-98 
* 
229 
100-00 
The compound of hydrate of silver with diazobenzol is insoluble in all the ordinary 
neutral solvents. Nitric acid even when cold dissolves it with great facility. It is 
distinguished by great stability; for even after having been kept for weeks, not the least 
sign of decomposition could be discovered. Exposed to a higher temperature it explodes 
with some violence. Since the constitution of the two compounds just described affords 
sufficiently fixed data for establishing the composition of other combinations of metallic 
hydrates with diazobenzol, I have not thought it necessary to extend my analyses to the 
other salts. 
Their preparation and constitution, moreover, present no important characteristics, 
and I will therefore describe them very briefly. 
Compound of Hydrate of Barium with Biazobenzol 
is obtained when a solution of a very soluble barium-salt is added to a rather concern 
trated solution of the potassium-compound. It is precipitated in the form of white, 
microscopic, indistinct needles or plates, which become yellowish in consequence of a 
gradual decomposition. It is difficultly soluble in water. 
The compound of diazobenzol with hydrate of zinc is a white amorphous powder 
insoluble in water. The compound with hydrate of lead is also a white powder, but 
acquiring rapidly a yellow colour. With sulphate of copper a brown precipitate changing 
to green is obtained. Mercurial chloride gives no precipitate. 
Biazobenzol , G 6 H 4 N 2 . 
This remarkable substance is obtained when an aqueous solution of the compound of 
hydrate of potassium with diazobenzol is treated with a sufficient quantity of acetic acid. 
A thick yellow oil is liberated, which possesses a peculiar odour, and is remarkable for 
its extraordinary instability. Its existence is very ephemeral, and after a short time 
nitrogen gas begins to be evolved, and the oil is rapidly converted into a brownish-red 
substance. The heat which is produced when larger quantities of the oil undergo this 
spontaneous decomposition is sufficient to give rise to dangerous explosions. 
The addition of ether to the oil dissolves it instantaneously, producing a red solution, 
a tumultuous evolution of gas taking place. It combines with nitric and sulphuric acids, 
and with hydrate of potassa, terchloride of gold, &c., forming the compounds previously 
described. 
4x2 
