Über die Reaktion von Mn3O4 mit Säuren

Abstract

Mn₃O₄ dissolves with an excess of H⁺ in water into Mn²⁺ and Mn³⁺ ions. The latter undergoes a disproportionation into Mn²⁺ and γ-MnO₂ of very poor crystallinity. In effect 2 of the 3 Mn are found in the solute phase. Prolonged standing or boiling of this γ-MnO₂ in excess acid leads to a recrystallisation and subsequent nucleation of β-MnO₂. Otherwise (i.e. with little acid) the solid product of the reaction of Mn₃O₄ with HNOa is γ-MnOOH.