Density Functional Theory Study of The Decomposition of Mg(OH)2: a Lamellar Dehydroxylation Model
- Publication Type
- Original research
- Authors
- A.V.G. Chizmeshya
- M.J. McKelvy
- R. Sharma
- R.W. Carpenter
- Hamdallah A. Béarat
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.
- Title
- Materials Chemistry and Physics, Volume 77, Issue 2, 15 January 2003, Pages 416–425
- Publisher
- --
- Publisher Country
- Palestine
- Publication Type
- Both (Printed and Online)
- Volume
- --
- Year
- 2003
- Pages
- --