Novel modification of anhydrous transition metal oxalates from powder diffraction
| Autor: | Anna N. Puzan, Pavel V. Mateychenko, Vyacheslav N. Baumer |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
Phase transition
Rietveld refinement Chemistry Inorganic chemistry 02 engineering and technology Crystal structure 010402 general chemistry 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences 0104 chemical sciences Inorganic Chemistry Crystal Crystallography Transition metal Materials Chemistry Orthorhombic crystal system Physical and Theoretical Chemistry Isostructural 0210 nano-technology Powder diffraction |
| Zdroj: | Acta Crystallographica Section C Structural Chemistry. 73:911-916 |
| ISSN: | 2053-2296 |
| Popis: | The known metal–C2O4 structures may be divided into two modifications, α and β. The α-modification has an order–disorder struxture, revealing one-dimensional disordering of the metal–oxalate chains, and the β-modification is ordered. The crystal structures of orthorhombic γ-MnC2O4 {poly[μ-oxalato-manganese(II)]; space group Pmna, a = 7.1333 (1), b = 5.8787 (1), c = 9.0186 (2) Å, V = 378.19 (1) Å3, Z = 4 and Dx = 2.511 Mg m−3} and γ-CdC2O4 {poly[μ-oxalato-cadmium(II)]; space group Pmna, a = 7.3218 (1), b = 6.0231 (1), c = 9.2546 (2) Å, V = 408.13 (1) Å3, Z = 4 and Dx = 3.262 Mg m−3} have been obtained from powder diffraction patterns. The structures are isostructural. Each metal atom in each structure is coordinated by seven O atoms which belong to five oxalate ions. The crystal packing, which contains noticeable cavities in the [101] and [001] directions, is not close packed and essentially differs from the known disordered α- and ordered β-modifications of transition metal oxalates. This modification seems to be metastable. It was found that a spontaneous γ→β phase transition takes place for γ-CdC2O4. |
| Databáze: | OpenAIRE |
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