| Autor: |
Menezes, Luke T., Richtik, Brooke N., Assoud, Abdeljalil, Zeljkovic, Ivan D., Farahi, Nader, Dolgos, Michelle, Kleinke, Holger |
| Zdroj: |
Inorganic Chemistry; January 2023, Vol. 62 Issue: 1 p285-294, 10p |
| Abstrakt: |
Herein, the crystal structures and physical properties of two previously unreported barium seleno-germanates, Ba6Ge2Se12and Ba7Ge2Se17, are presented. Ba6Ge2Se12adopts the P21/cspace group with a= 10.0903(2) Å, b= 9.3640(2) Å, c= 25.7643(5) Å, and β = 90.303(1)°, whereas Ba7Ge2Se17crystallizes in the Pnmaspace group with a= 12.652(1) Å, b= 20.069(2) Å, c= 12.3067(9) Å. Both structures feature polyatomic anion disorder: [Se2]2–in the case of Ba6Ge2Se12and [GeSe5]4–in the case of Ba7Ge2Se17. The anion disorder is verified by comparing pair distribution functions of ordered and disordered models of the structures. These anions are split unevenly across two possible sets of atomic coordinates. The optical band gaps obtained from the powdered samples are found to be 1.75 and 1.51 eV for Ba6Ge2Se12and Ba7Ge2Se17, respectively. Differential scanning calorimetry experiments indicate that the compounds are stable under the exclusion of air up to at least 673 K. The thermal diffusivity measurements revealed thermal conductivities reaching values as low as 0.33 W m–1K–1in both compounds at 573 K. |
| Databáze: |
Supplemental Index |
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