Synthesis of CaMnO3 from (Ca0.5Mn0.5)CO3

Taguchi, Hideki; Kuniyoshi, Y.; Nagao, Mahiko

doi:10.1007/bf01729961

Cited by 6 publications

(1 citation statement)

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“…Additional diffraction peaks at 32.99 and 40.38 °2θ ( d =2.713 and 2.232 Å) with relative intensities lower than 0.5% were detected. The corresponding spurious phase is different to that found by Taguchi et al (1989b); the peaks represent the strongest lines of CaMn 2 O 4 , marokite [the same secondary phase in the CaMnO 3 sample as that reported by Santhosh et al (2000) and Bocher et al (2009)]. The refined lattice parameters of CaMnO 3 are a =5.281 59(4) Å, b =7.457 30(4) Å, and c =5.267 48(4) Å as derived from run 2.…”

Section: Sample Microstructure Morphology and Structurecontrasting

confidence: 94%

Lattice parameters and orthorhombic distortion of CaMnO₃

et al. 2010

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CaMnO 3 is a parent compound for numerous multicomponent manganese perovskite oxides. Its crystallographic data are of primary importance in the science and technology of functional CaMnO 3 -based materials. In the present study, data were collected for a CaMnO 3 sample at 302 K. The crystal structure refinement yields accurate absolute values of lattice parameters, a = 5.281 59͑4͒ Å, b = 7.457 30͑4͒ Å, and c = 5.267 48͑4͒ Å, leading to orthorhombic distortion of ͑c / a , ͱ 2c / b͒ = ͑0.997 33, 0.998 95͒. The orthorhombic distortion of the CaMnO 3 structure is discussed on the basis of comparison of our unit-cell size with data already published. At a graphical representation of the distortion, it is observed that there is a considerable scatter of the distortion values among the literature data but, interestingly, a considerable fraction of experimental results ͑including the present one͒ for stoichiometric samples are grouped around the distortion ͑c / a , ͱ 2c / b͒ = ͑0.9973, 0.9990͒, which lies close to a maximum in the extent of orthorhombicity. The influence of off-stoichiometry on the orthorhombic distortion is discussed on the basis of available experimental data. Simulations, employing a mean-field approach for low temperatures, predict an increase in cell volume and structural distortions with the concentration of oxygen vacancies when the additional electrons are localized on the manganese. A simple model of delocalization produced the opposite effect, which is expected to combine with lattice vibrations to recover the cubic phase at high temperatures.

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Section: Sample Microstructure Morphology and Structurecontrasting

confidence: 94%