Structure disordering and thermal decomposition of manganese oxalate dihydrate, MnC2O4·2H2O
| Autor: | Anna N. Puzan, Dmytro Lisovytskiy, Pavel V. Mateychenko, Vyacheslav N. Baumer |
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| Rok vydání: | 2018 |
| Předmět: |
Materials science
Thermal decomposition Ab initio Recrystallization (metallurgy) 02 engineering and technology Crystal structure 010402 general chemistry 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences 0104 chemical sciences Electronic Optical and Magnetic Materials Amorphous solid Inorganic Chemistry Crystallography Transition metal Materials Chemistry Ceramics and Composites Physical and Theoretical Chemistry 0210 nano-technology Single crystal Powder diffraction |
| Zdroj: | Journal of Solid State Chemistry. 260:87-94 |
| ISSN: | 0022-4596 |
| DOI: | 10.1016/j.jssc.2018.01.022 |
| Popis: | It is found that the known regular structures of MnC2O4·2H2O (I) do not allow to refine the powder X-ray pattern of (I) properly using the Rietveld method. Implementation of order-disorder scheme [28] via the including of appropriate displacement vector improves the refinement results. Also it is found that in the case of (I) the similar improvement may be achieved using the data on two phases of (I) obtained as result of decomposition MnC2O4·3H2O single crystal in the mother solution after growth. Thermal decomposition of (I) produce the anhydrous γ-MnC2O4 (II) the structure of which is differ from the known α- and β-modifications of VIIIb transition metal oxalates. The solved ab initio from the powder pattern structure (II) (space group Pmna, a = 7.1333 (1), b = 5.8787 (1), c = 9.0186 (2) A, V = 378.19 (1) A3, Z = 4 and Dx = 2.511 Mg m−3) contains seven-coordinated Mn atoms with Mn–O distances of 2.110–2.358 A, and is not close-packed. Thermal decomposition of (II) in air flows via forming of amorphous MnO, the heating of which up to 723 K is accompanied by oxidation of MnO to Mn2O3 and further recrystallization of the latter. |
| Databáze: | OpenAIRE |
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