Solid manganese carbonate is slowly added to a stoichiometric amount of aqueous hydrobromic acid. The solution is then poured into an evaporation dish and heated on a hot plate to remove most of the water, further dried with a vacuum desiccator. The pure product is obtained as a tetrahydrate and it is stored in an inert atmosphere.
MnCO3 + 2 HBr = MnBr2 + CO2 + H2O
MnBr2 + 4 H2O = MnBr2 · 4H2O
Addition of the carbonate
The solution after complete addition
Evaporation of the water
Further removal of the water