134 Johnson and Chittenden—New Acid Ammonium Sulphates. 
crystals formed. These B were separated and dried at 100 C. 
These crystals proved to be normal ammonium sulphate. 
They yielded by analysis— 
A B Calculated. 
(NH,),. 39°33 39°46 39°39 
The alcoholic mother-liquor was evaporated on the water- 
bath and left a small fluid residue, which on cooling deposited 
a few crystals, apparently of normal sulphate. The few drops 
of liquid remaining were intensely acid and had all the char- 
acters of sulphuric acid discolored by organic matters. Treat- 
ment with aqueous alcohol thus resolves both the bisulphate 
(two molecules) and the pyrosulphate into normal sulphate and 
sulphuric acid, or in part probably into sulphethylic acid. 
In the first stage of the decomposition of ammonium sul- 
phate at a temperature “a little higher than the boiling point of . 
mercury” the vapors are alkaline. The chemical change would 
appear to involve six molecules of the sulphate, which lose five 
molecules of ammonia gas and one molecule of water vapor, 
leaving as solid residue a mixture of one molecule of unchanged 
sulphate, one of pyrosulphate and three of bisulphate. 
a a le rir! Opal 
(NH,).S,0,-+(NH,).50, 
In these changes two molecules of sulphate yield one mole- 
cule of pyrosulphate with loss of one water- and two ammonia- 
molecules,* while three molecules of sulphate yield, each, a 
molecule of bisulphate, with loss of a molecule of ammonia,t 
and the sixth molecule of sulphate comes out unaltered. 
In the second stage of heating (near incipient redness) the 
fumes are at first alkaline, but shortly become acid, and con- 
tinued so as long as that temperature is maintained. 
The changes are empirically expressed as follows: 
S,0,,N,H,,—[280,+2H,0+3NH,]=S,0,,N.Hie, 
or rationally— 
[3(NH,HSO,)+(NH,).S,0, + (NH,),S0,] —[2S0,+2H,0+ 
3NH, |=2(NH,HSO,)+(NH,).8,0,. 
The rise of temperature from 350° to 520° C. appears not to 
alter the pyrosulphate and bisulphate, but the chemical change 
to result from a molecule of sulphate reacting on a mole- 
cule of bisulphate, whereby both are decomposed, thus— 
NH,HSO,+(NH,),80,=280,4+2H,0+3NH,. 
It would be interesting to study the reactions at other 
tem peratures. 
ONH. 
80s<oxn* 80, / ONH, 
* NE, gs 0+2NH,]=<, >0 
ONH. ? 3+" S80, 
SO.< : ~ONH, 
+ 380,<0N Ht —3NH,=380:<On- 
