Sulphate of manganese 44·50
Peroxide of manganese 18·90
Protoxide of manganese 36·60
------
100·00
--is next mixed with nitrate of soda and heated to 300° C., yielding
sulphate of soda and nitrate of manganese, the latter, however, being at
once decomposed into peroxide of manganese, and nitrogen peroxide, thus:--
_a._ MnSO_{4} + 2NaNO_{3} = Mn(NO_{3})_{2} + Na_{2}SO_{4}.
_b._ Mn(NO_{3})_{2} = MnO_{2} + 2NO_{2}.
After the mass has cooled, the sulphate of soda is washed out, the residue
yielding, according to the inventor, a material equal to native peroxide
of manganese.
4. Schlösing. Manganese is acted upon with a mixture of hydrochloric and
nitric acids, the degree of concentration of the acids being so regulated
by the addition of water that the mixture yields only chlorine, whilst
protonitrate of manganese is formed; this salt being calcined yields
peroxide of manganese and nitric acid. The nitric acid aids the oxygen of
the air in decomposing the hydrochloric acid.
The following equation will explain the successive stages of the
reaction:--
_a._ 2HCl + 2HNO_{3} + MnO_{2} = Cl_{2} + Mn(NO_{3}) + 2H_{2}O.
_b._ Mn(NO_{3})_{2} = MnO_{2} + 2NO_{2}.
_c._ 2NO_{2} + H_{2}O + O = 2HNO_{3}.
5. Vogel. By decomposing chloride of copper by heat. The chloride in the
crystalline state is mixed with half its weight of sand and heated in
earthenware retorts to 200° to 300° C., yielding chlorine gas, while the
remaining protochloride of copper is reconverted into perchloride by the
action of hydrochloric acid.