An unquenchable perovskite phase of MgGeO3 and comparison with MgSiO3 perovskite

K. Leinenweber, Wang Yanbin Wang, T. Yagi, H. Yusa

Research output: Contribution to journalArticle

63 Scopus citations

Abstract

An unquenchable polymorph of MgGeO3, having a perovskite structure, has been observed using in situ X-ray diffraction in a diamond-anvil cell. The perovskite polymorph formed at room temperature and 12-14 GPa by pressure-induced phase transition from the lithium niobate phase of MgGeO3. It is indexed on an orthorhombic lattice, with unit-cell parameters a = 4.832(11), b = 5.03(13), c = 7.022(16) Å, and V = 170.7(5) Å3 at 17.9 GPa. The transition is fully reversed during decompression. Like MgSiO3 perovskite, MgGeO3 perovskite only becomes thermodynamically stable at very high pressures (over 23 GPa). Unlike MgSiO3, it also becomes unstable relative to the lithium niobate phase during pressure release. The latter property accounts for the lack of observation of the perovskite phase in previous studies of MgGeO3 as an analogue material. -Authors

Original languageEnglish (US)
Pages (from-to)197-199
Number of pages3
JournalAmerican Mineralogist
Volume79
Issue number1-2
StatePublished - Jan 1 1994
Externally publishedYes

ASJC Scopus subject areas

  • Geophysics
  • Geochemistry and Petrology

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