As discussed in my answer, manganese is not particularly reactive to air. The surface of manganese lumps oxidize to a minor extent but when it is finely divided, it becomes pyrophoric and burns in air. It tends to form the oxide $\ce{Mn3O4}$ and the nitride $\ce{Mn3N2}$. It was fine until I came across this statement from Concise Inorganic Chemistry by J.D.LEE:
The finely divided metal is pyrophoric in air, but the massive metal does not react until heated. When strongly heated, the massive metal reacts with many non-metals such as $\ce{O2, N2, Cl2}$ and $\ce{F2}$, forming $\ce{Mn3O4, Mn3N2, MnCl2}$ and a mixture of $\ce{MnF2}$ and $\ce{MnF3}$
I was under the impression that manganese is relatively inert and normally won't oxidize unless it is powdered but the book says otherwise. Nowhere, I found any source backing the statement.
Question: Does solid manganese reacts with atmospheric air when heated (if so, at what temparture)?