Autor: |
Michael J. McKelvy, Renu Sharma, Hamdallah Bearat, Andrew Chizmeshya, Ray Carpenter |
Rok vydání: |
2003 |
Předmět: |
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Zdroj: |
Materials Chemistry and Physics. 77:416-425 |
ISSN: |
0254-0584 |
Popis: |
We present a density functional theory investigation of the decomposition of Mg(OH)2. Based on recent experiments indicating a lamellar dehydroxylation process we have calculated the energetics, elastic behavior and structural trends of a series of oxyhydroxide intermediates of composition Mgx+yOx(OH)2y representing a solid solution series between brucite (Mg(OH)2) and periclase (MgO). Using a variationally induced breathing (VIB) ionic approach we find that this broad range of lamellar oxyhydroxide intermediate materials becomes thermodynamically accessible at temperatures near 500 °C. The computed dehydroxylation dependence of the compressibility is found to vary dramatically with the initial formation of periclase-like oxide layers displaying an abrupt jump to a value near that of periclase (∼160 GPa). In contrast to this very non-linear behavior the basal plane lattice parameter a is found to exhibit a nearly linear (Vegard-like) dependence on hydroxyl content. |
Databáze: |
OpenAIRE |
Externí odkaz: |
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