The first hafnium germanate with garnet-type of structure: Mild hydrothermal synthesis, crystal structure and new mechanism of hydroxyl inclusion
| Autor: | Stanislav Ferdov, Zhi Lin |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
Hydroxyl inclusion
Materials science Ab initio chemistry.chemical_element 02 engineering and technology Crystal structure 010402 general chemistry 01 natural sciences Hydrothermal circulation Hydrogarnet Inorganic Chemistry Disorder Materials Chemistry Hydrothermal synthesis Germanate Physical and Theoretical Chemistry Hydrogrossular Hafnium garnet 021001 nanoscience & nanotechnology Condensed Matter Physics 0104 chemical sciences Electronic Optical and Magnetic Materials Hafnium Crystallography Octahedron chemistry Ceramics and Composites Nanoparticles 0210 nano-technology |
| Zdroj: | Journal of Solid State Chemistry. 273:117-121 |
| ISSN: | 0022-4596 |
| DOI: | 10.1016/j.jssc.2019.02.031 |
| Popis: | Sodium hafnium germanate, Na3Hf1.7Ge3O10(OH)1.8, with garnet-type of structure was synthesized as a single phase, nanoparticles (100–600 nm) at mild hydrothermal conditions (230 °C) and autogenous pressure. The structure was solved ab initio from powder X-ray diffraction data and subsequently refined [Rexp: 6.10, Rwp: 7.26, Rp: 5.39, GOF: 1.19, RB: 1.50] by the method of Rietveld. The solid crystallizes in cubic space group Ia-3d (230), with a = 12.6819(2) A, V = 2039.65(1) A3 and Z = 8. The structure is built up of rare combination of two tetravalent (Ge4+ and Hf4+) and one monovalent (Na+) cation alternating in form corner-sharing GeO4 tetrahedra and HfO6 octahedra whose negative charge is compensated by Na+ residing in dodecahedral coordination. Unlike the typical tetrahedral site disorder in hydrogarnets (hydrogrossular, hibschite, and katoite) we found that the octahedral position of the heavy Hf4+ cation is partly vacant which reveals alternative mechanism of charge unbalance leading to incorporation of hydroxyl group. Furthermore, the synthesized material is the first hafnium germanate with garnet-type of structure and the second known sodium hafnium germanate. |
| Databáze: | OpenAIRE |
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