r 130 ] 
XXII. On the Decomposition of the Neutral Sulphate of 
the Peroxide of Iron hy boiling Us Solution, By Th. 
SCHEERER.* 
A CONCENTRATED solution of the neutral sulphate of 
iron may be heated to boiling without becoming opake, 
but if one part of this salt be dissolved in 40 parts of water, 
continued boiling precipitates traces of a basic salt, which in- 
crease so as to form a considerable precipitate the more the 
solution is diluted with water. 
This salt is a combination of sulphuric acid, peroxide of 
iron and water, in the following proportions : 
74*70 peroxide of iron. 
12*57 sulphuric acid. 
12*70 water. 
99*97 
Thus it consists of 6 atoms of the peroxide of iron, 2 atoms 
of sulphuric acid, and 9 atoms of water; the theoretical 
composition, therefore, would be 
74*46 
12*71 
12*83—100*00 
and accordingly the formula of Berzelius is 2 hV S + 9 H, 
or 2 (Fe S -f 8 Fe) + 27 H. 
According to the nomenclature of Berzelius, this salt may 
be called the eight-fold basic sulphate of the peroxide of iron. 
The oxygen of the water amounts to the half of that in the 
oxide, being quite analogous to the five- fold basic salt which 
is produced by the oxidation of a solution of sulphate of iron 
in the open air. 
Dried at 212° Fahr., this salt forms a dark orange yellow 
powder, its colour being lighter in proportion as the solution 
is previously diluted, and the less it is boiled. It is not 
dissolved by water, but pretty readily by acids. At a tem- 
perature below a dull red heat, it loses its water and becomes 
of a dark brown colour. At a red heat the sulphuric acid is 
expelled and the peroxide of iron is left behind. 
Experiments were made to discover how much of the 
sulphate of iron was decomposed by various degrees of dilu- 
* Communicated by the x'^uthor, to whom we beg to return om* kind 
tlianks. The present extract forms the substance of two distinct articles, 
published in PoggendorfF’s Annalen, vol, xlii. p. 104, and vol. xliv. 
p. 453 . — Edit. 
