Density functional theory study of the decomposition of Mg(OH)2: A lamellar dehydroxylation model

Andrew Chizmeshya, M. J. McKelvy, R. Sharma, Ray Carpenter, H. Bearat

Research output: Contribution to journalArticle

23 Scopus citations

Abstract

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 (∼160GPa). 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.

Original languageEnglish (US)
Pages (from-to)416-425
Number of pages10
JournalMaterials Chemistry and Physics
Volume77
Issue number2
DOIs
StatePublished - Jan 15 2003

Keywords

  • Computer simulation
  • Density functional theory
  • Intermediate phases
  • Mg(OH)
  • MgO
  • Oxyhydroxide
  • Reactivity

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics

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