Abstract
Abstract
Spinel-type MnIn2O4 materials are synthesized at 500 °C from an In3+–Mn3+ co-precipitate; the synthesis is based on the in situ reduction of Mn3+ to Mn2+ during calcination. The structure refinement of the powder X-ray diffraction data reveals that the degree of inversion i of the (View the MathML source)[View the MathML source]O4 spinel synthesized in the air and N2 is small (i=0.08) and increases to 0.30 for the spinel synthesized in Ar. The distribution of Mn cations over tetrahedral and octahedral sites is confirmed by X-ray absorption near-edge spectroscopy. As shown by the high-temperature in situ X-ray diffractometry, MnIn2O4 spinel is stable against oxidation in the air up to 550 °C. The in situ X-ray diffraction experiments in a diamond anvil cell reveal that MnIn2O4 is stable up to 22 GPa at room temperature. The bulk modulus B0 and its first pressure derivative View the MathML source determined by the third-order Birch–Murnaghan equation of state are 139.8(4) GPa and 5.4(5), respectively.