CHEMICAL Suwa 
Dec. 8, 1882. 
The Leclanche Cell. 
259 
THE CHEMICAL NEWS, 
| 3Zn(NH;3Cl),+20H,= 
=2HOZnNH;Cl4 (CIH,N), Zn(NH;CI),, 
Nem err” Nr 
Insoluble Soluble 
Zinco-monammonium Ammonium and Zinco- 
Chlore-hydroxide. di-ammonium Chloride. 
and the insoluble part hydrated, will be that which Davis 
examined, and to which he gave the improbable formula, 
Zn(OH),NH,CL 
Manganese dioxide—prepared free from lower oxides 
by heating manganese nitrate to 169° C., and thoroughly 
washing the resulting oxide—proved to be unaffedted by 
digesting it for a long time with a solution of ammonium 
chloride.* 
Manganese monoxide is slowly acted upon by ammonium 
chloride solution when cold, and much more rapidly when 
hot, ammonia being freely evolved, a little manganese 
going into solution, and the rest undergoing a striking 
transformation from its bright green self into a bright 
skin-coloured substance. This, by protraded washing on 
the filter-pump, becomes manganous hydroxide, with a 
very little chloride and peroxide (from agrial oxidation), 
and is probably, therefore, at first manganous hydroxy- 
chloride, HOMnCI, just possibiy ammoniated ; it needs 
further examination. Its formation may be symbolised 
thus .— 
MnO +NH,Cl=CIMnOH+NH;, 
The manganese going into solution will be, no doubt, in 
the form of double chloride of manganeseand ammonium. 
Intermediate oxides, both native and artificial, are acted 
upon by ammonium chloride solution, a little manganese 
dissolving, and the remaining oxide approaching more 
and more the dioxide in composition. ‘f'his oxide, how- 
ever, has not been reached, even by repeated digestion 
with fresh portions of ammonium chloride solution. Even 
excellent pyrolusite yielded soluble manganese, in conse. 
quence, no doubt, of the presence of psilomelane, or other 
manganous compound. 
Zinco-diammonium chloride dissolved in solution of 
ammonium chloride aés gradually upon artificially pre- 
pared hydrogen manganite, H,0,Mn,, not only so as to 
cause manganese to go into solution, but also as to preci. 
pitate zinc on the manganite. For after digesting the 
manganite in the solution, washing it with ammonium 
chloride solution, and then thoroughly with water till the 
washings were free from chloride, zinc could be easily 
detefled in it, though in small quantity. Before thig 
treatment it was found to be free from zinc. The washing 
with ammonium chloride was pradised as a precaution, 
although it was certain to remove some of the zinc from 
the manganite, The reaction must be as follows : — 
(NH3Cl)2Zn + H;0,Mn, =2NH,Cl+Zn0,Mn,, 
Native well crystallised manganite, ground very fine 
and subjetied to the action of the same solution, did nog 
appear to take up any zinc; nor did artificial sesquioxide 
and binoxide. 
Zing.and dioxide of manganese were left in conta& ina 
solution of aniinonium chloride. Pure dioxide, prepared 
by heating the nitrate, was employed for this purpose. 
Some evolution of hydrogen stil took place in contac 
with the zinc,+ both zinc and manganese compounds went 
into solution, and ammonia was set free. The solution 
deposited a dark brown substance, manganic hydrate, on 
the sides of the vessel in conta with the air, just as an 
ammoniacal solution of manganese always does through 
aérial oxidation. The solid manganese oxide was re- 
moved from the solution after some weeks, and washed 
VoL. XLVI, No. 1202. 
ON THE LECLANCHE CELL, 
AND THE REACTIONS OF MANGANESE 
OXIDES WITH AMMONIUM CHLORIDE. 
By EDWARD DIVERS, M.D, . 
Principal of the Japanese Imperial College of Engineering, 
THE occurrence of my name as a misprint for Davis, in 
an abstract in the July number of the Fournal of the 
Chemical Society, of Longi’s paper, on the Leclanché cell 
crystals, makes me desirous to publish that I bave never 
written a communication on this subje®. Somewhat 
oddly it happens, however, that I did work at it some 
years ago, with the assistance of one of my pupils, Mr. 
M. Kawakita, and as there seems to be nowhere a very 
satisfadlory statement of the chemistry of this cell, I take 
this opportunity to publish what I hold to be a more exa& 
account than has yet appeared, based upon experiments 
in only a few points absolutely new perhaps, but still 
proving fats apparently little known or considered, Some 
of these experiments have only just been made. I will 
first state the a@ion of zinc and of manganese oxides 
separately upon ammonium chloride solution, and then 
their combined action upcn it. 
Zinc is slowly acted upon by a solution of ammonium 
shloride, hydrogen gas being evolved, and a zinc com: 
pound appearing in the solution. The solution acquires 
an alkaline reaction, and an almost imperceptible odour 
of ammonia. The nature of the substances rea®ing, the 
properties of zinco-di-ammonium chloride, and the 
gradual separation of this salt in crystals in a Leclanché 
cell, leave no doubt that the zinc compound going into 
solution is zinco-di-ammonium chloride in combination 
with ammonium chloride. But because Longi has found 
crystals in a Leclanché cell which proved to be slightly 
impure ammonium chloride (a common experience, the 
crystals forming merely in consequence of the evaporation 
of the water), he appears unreasonably to doubt Priwoz- 
rik's statement, that Zn(NH;Cl);, zinco-di-ammonium 
chloride crystals, are formed in the normal working of the 
cell. 1 therefore mention that Mr. Kawakita found in 
:hese crystals nothing but ammonia, chlorine, and 38-6 per 
cent of zinc, the calculated quantity being 38:23 per cent. 
The properties of this salt, the knowledge of which bears 
ipon the explanation of the Leclanché cell, are that it is 
sparingly soluble in ammoniuin chloride solution, rendering 
it alkaline, but only faintly ammoniacal. Its solution 1s 
not decomposed by dilution with water. It must be re- 
garded as going into solution as double chloride of am- 
monium and zinco-di-ammonium, (CIH,N)zZn(NH;Cl),. 
Un heating the solution much ammonia escapes, with 
most probably the formation of double chloride of zinc 
and ammonium, thus,— 
(CIH NN), Zn(NH;3Cl), =2NH;+ (CIH N);'ZaCl,. 
The solution remains clear after boiling. Zinco-di-am- 
monium chloride is decomposed by water alone into an 
asoluble part and a soluble part. ‘The insoluble part is 
voluminous and flocculent when very finely-ground salt 
is employed, otherwise it is granular. It yields much 
ammonia, hydroxyl, and chlorine to analysis, but being 
slowly decomposed by washing, it has not been analysed 
quantitatively. The other and soluble part also consists 
of zinc, chlorine, and ammonia or ammonium. The a&ion 
of water is therefore probably expressed by the following 
equation ;— 
* In* Watts's Dictionary,” 2nd Suppl, p. 448, manganese dioxide 
is spoken of as sting on ammonium chloride solution. This is a 
mistake, apparently, through inadvertence, as it is not a direct state- 
ment, and has no eal connection with the context, 
+ In Sylvanus Thoon:pson’s little book on Eledtricity, hydrogen is 
said to be liberated on the manganese dioxide when in galvanle 
circuit, this hydrogen being only slowly oxidised, But this [ take to 
be an assumption, made to explain the rapid fall of the ele@romotive 
force of the cell through * polarisation,” and gradual rise again when 
out of action, and not an assertion of observed fact,