Chemical reactions of the elements
Reaction of manganese with air
Manganese is not particularly reactive to air, despite it being a little more electropositive than its neighbours in the periodic table. The surface of manganese lumps oxidize to a minor ecxtent. When finely divided, manganese metal burns in air. It burns in oxygen to form the oxide Mn3O4 and in nitrogen to form the nitride Mn3N2.
3Mn(s) + 2O2(g) → Mn3O4(s)
3Mn(s) + N2(g) → Mn3N2(s)
Reaction of manganese with water
Manganese does not react with water under normal conditions.
Reaction of manganese with the halogens
Manganese burns in chlorine to form manganese(II) chloride, MnCl2. It also reacts with bromine or iodine to form respectively manganese(II) bromide, MnBr2, or manganese(II) iodide, MnI2. The corresponding reaction between the metal and fluorine, F2 affords the fluorides manganese(II) fluoride, MnF2 and manganese (III) fluoride, MnF3.
Mn(s) + Cl2(g) → MnCl2(s)
Mn(s) + Br2(g) → MnBr2(s)
Mn(s) + I2(g) → MnI2(s)
Mn(s) + F2(g) → MnF2(s)
2Mn(s) + 3F2(g) → 2MnF3(s)
Reaction of manganese with acids
Manganese metal dissolves readily in dilute sulphuric acid to form solutions containing the aquated Mn(II) ion together with hydrogen gas, H2. In practice, the Mn(II) is present as the virtually colourless complex ion [Mn(OH2)6]2+.
Mn(s) + H2SO4(aq) → Mn2+(aq) + SO42-(aq) + H2(g)
Reaction of manganese with bases