Gurlo, Aleksander ; Kroll, Peter ; Riedel, Ralf (2008)
Metastability of Corundum-Type In2O3.
In: Chemistry - A European Journal, 14 (11)
doi: 10.1002/chem.200701830
Artikel, Bibliographie
Kurzbeschreibung (Abstract)
he description of structural relations between bixbyite- and corundum-type structures is of particular interest because of the common occurrence of both structures. One of the representative examples of the bixbyite to corundum transition is the high-pressure high-temperature synthesis of the corundum-type indium oxide. The wet chemistry synthesis and stabilisation of the corundum-type In2O3 under ambient pressure conditions calls for a re-interpretation of the In[BOND]O phase diagram as well as for the clarification of the phase transitions in In2O3. One of the questions to be clarified is the stability of the corundum-type In2O3. In the present work we studied the stability of the corundum-type In2O3 both theoretically (by density-functional calculations) and experimentally. The synthesis of the corundum-type In2O3 was performed by the modified non-alkoxide sol–gel method based on the ammonia-induced hydrolysis of indium nitrate in methanol. The corundum-type In2O3 was subjected to thermal analysis (STA) as well as to structural studies, that is, it was examined using X-ray powder diffraction (XRPD) including in situ XRPD characterisation upon thermal treatment. For the first time we have undoubtedly demonstrated, both theoretically and experimentally, the metastability of the corundum-type In2O3 polymorph. The In2O3 polymorph appears to be metastable throughout the entire enthalpy–pressure phase diagram. Upon heating, corundum-type In2O3 transforms irreversibly into cubic bixbyite-type In2O3 as shown by STA as well as in situ heating XRPD experiments. Computations indicate the existence of another high-pressure modification of In2O3 with orthorhombic structure, iso-typic to Rh2O3-II. We predict this new phase to form at pressures exceeding 15 GPa from both the cubic bixbyite-type and the corundum-type modification of In2O3.
| Typ des Eintrags: | Artikel |
|---|---|
| Erschienen: | 2008 |
| Autor(en): | Gurlo, Aleksander ; Kroll, Peter ; Riedel, Ralf |
| Art des Eintrags: | Bibliographie |
| Titel: | Metastability of Corundum-Type In2O3 |
| Sprache: | Englisch |
| Publikationsjahr: | 7 April 2008 |
| Verlag: | Wiley |
| Titel der Zeitschrift, Zeitung oder Schriftenreihe: | Chemistry - A European Journal |
| Jahrgang/Volume einer Zeitschrift: | 14 |
| (Heft-)Nummer: | 11 |
| DOI: | 10.1002/chem.200701830 |
| Kurzbeschreibung (Abstract): | he description of structural relations between bixbyite- and corundum-type structures is of particular interest because of the common occurrence of both structures. One of the representative examples of the bixbyite to corundum transition is the high-pressure high-temperature synthesis of the corundum-type indium oxide. The wet chemistry synthesis and stabilisation of the corundum-type In2O3 under ambient pressure conditions calls for a re-interpretation of the In[BOND]O phase diagram as well as for the clarification of the phase transitions in In2O3. One of the questions to be clarified is the stability of the corundum-type In2O3. In the present work we studied the stability of the corundum-type In2O3 both theoretically (by density-functional calculations) and experimentally. The synthesis of the corundum-type In2O3 was performed by the modified non-alkoxide sol–gel method based on the ammonia-induced hydrolysis of indium nitrate in methanol. The corundum-type In2O3 was subjected to thermal analysis (STA) as well as to structural studies, that is, it was examined using X-ray powder diffraction (XRPD) including in situ XRPD characterisation upon thermal treatment. For the first time we have undoubtedly demonstrated, both theoretically and experimentally, the metastability of the corundum-type In2O3 polymorph. The In2O3 polymorph appears to be metastable throughout the entire enthalpy–pressure phase diagram. Upon heating, corundum-type In2O3 transforms irreversibly into cubic bixbyite-type In2O3 as shown by STA as well as in situ heating XRPD experiments. Computations indicate the existence of another high-pressure modification of In2O3 with orthorhombic structure, iso-typic to Rh2O3-II. We predict this new phase to form at pressures exceeding 15 GPa from both the cubic bixbyite-type and the corundum-type modification of In2O3. |
| Freie Schlagworte: | ab initio calculations, indium oxide, indium, metastable compounds, phase transitions |
| Fachbereich(e)/-gebiet(e): | 11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft > Fachgebiet Disperse Feststoffe 11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft 11 Fachbereich Material- und Geowissenschaften |
| Hinterlegungsdatum: | 16 Apr 2012 09:30 |
| Letzte Änderung: | 05 Mär 2013 10:00 |
| PPN: | |
| Sponsoren: | Funded by Fonds der Chemischen Industrie |
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