Two new magnesium and magnesium-lead fluorogermanates and revision of the Mg28Ge7.5O38F10 phase
| Autor: | S. A. Novikov, Rabaya Bagum, Z. Blossom Yan, Yurij Mozharivskyj, J. Patrick Clancy |
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| Rok vydání: | 2021 |
| Předmět: |
Magnesium fluoride
Flux method Chemistry Magnesium Infrared spectroscopy chemistry.chemical_element 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences Silicate 0104 chemical sciences Electronic Optical and Magnetic Materials Inorganic Chemistry Crystal chemistry.chemical_compound Crystallography Norbergite Materials Chemistry Ceramics and Composites Physical and Theoretical Chemistry 0210 nano-technology Single crystal |
| Zdroj: | Journal of Solid State Chemistry. 293:121741 |
| ISSN: | 0022-4596 |
| DOI: | 10.1016/j.jssc.2020.121741 |
| Popis: | A new compound, Mg3Ge1-δO4(1-δ)F2(1+2δ) was obtained by high temperature solid state reactions and flux method and its structure was characterized by single crystal X-ray diffraction. The structure relates to the silicate mineral norbergite, Mg3SiO4(OH)F, a member of the humite mineral group. The diffraction experiment revealed a deficiency of the Ge site in the new structure, which can be compensated by the substitution of either OH− groups or F− anions for O2− anions. The combination of the NMR, neutron scattering, and IR spectroscopy experiments suggest that the F− substitution is most likely; thus, the Mg3Ge1-δO4(1-δ)F2(1+2δ) formula is suggested. The F− substitution is present for the side product of the Mg3Ge1-δO4(1-δ)F2(1+2δ) synthesis, the compound known as Mg28Ge7.5O38F10. Refinement of the twined Mg28Ge7.5O38F10 crystal showed a slightly higher Ge content and the final composition was assigned as Mg28Ge8O40F8. The PbF2 flux method yielded a new compound, Mg2Pb2Ge2O7F2. The structure of this digermanate is related to the group of naturally occurring and synthetic silicates containing R3+ cations. High-temperature powder XRD experiments showed that the Mg3Ge1-δO4(1-δ)F2(1+2δ) phase cannot be synthesized from Mg2GeO4 and MgF2 in air due to the transformation of magnesium fluoride into MgO. |
| Databáze: | OpenAIRE |
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