In situ Thermal Magnetic Investigation of γ-MnC2O4.2H2O Decomposition

Abstract

Prismatic, well-shaped crystals of orthorhombic γ-MnC2O4.2H2O were obtained by phase transformation of the initially synthesized MnC2O4.3H2O and characterized by XRD, SEM, DTA and DTG analyses. The results from in situ thermal magnetic measurements were compared with those of the monoclinic α-MnC2O4.2H2O and orthorhombic MnC2O4.3H2O. At γ-MnC2O4.2H2O the magnetic interaction between Mn(II) ions is most intensive and before the beginning of decomposition it changes twice from antifferoto ferromagnetic. For all crystal forms of the manganese(II) oxalate, the oxidative decomposition leads not only to Mn(III) but also to Mn(IV). However, the oxidation ability of Mn(II) is highest in monoclinic α-MnC2O4.2H2O and similar for both orthorhombic crystal forms.