We found that when the precursors CaMnO3 and Ca2MnO4 are reduced with any one of a variety of inorganic (H2, NH3) or organic (C2H4, C3H6) reducing agents between 300 and 500°C, topotactic reaction occurs to produce the ordered oxygen-defect phases CaMnO2.5 and Ca2MnO3.5, respectively. Orthorhombic cell constants for CaMnO2.5 are a = 5.43(1), b = 10.24(1), and c = 3.74(1) Å, and for Ca2MnO3.5 are a = 5.30(1), b = 10.05(1), and c = 12.24(1)Å. These compounds were characterized by powder X-ray diffraction, thermogravimetric analysis, magnetic susceptibility, and infrared spectroscopy. The reduced compounds reversibly oxidize to their respective precursor in oxygen at low temperatures.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Ceramics and Composites
- Condensed Matter Physics
- Physical and Theoretical Chemistry
- Inorganic Chemistry
- Materials Chemistry