Raman study of 3.65 Å-phase MgSi(OH)6 under high pressure and the bands assignment

Ulyana Borodina, Sergey Goryainov, Aleksandr Oreshonkov, Anton Shatskiy, Sergey Rashchenko

Research output: Contribution to journalArticlepeer-review

Abstract

3.65 Å-phase (or hydroxide-perovskite), MgSi(OH)6, is a representative of dense hydrous magnesium silicates (DHMS) with maximum water content (up to ∼35 wt.% H2O) and thus is of interest as one of the largest repositories of water among all the known hydrous phases. Sample of 3.65 Å-phase, grown in DIA-type multianvil apparatus, was studied by Raman spectroscopy under pressure up to ∼7 GPa with diamond anvil cell. Interpretation of the Raman spectrum was carried out using lattice-dynamical simulations within ab initio DFT method (CASTEP code). Additionally, OH-stretching bands are analyzed with two phenomenological models: empirical model by Novak and Libowitzky, using correlation between O–O distance and the wavenumber of the OH-stretching band, and theoretical model, using double Morse potentials of hydrogen bond O–H···O. Upon the pressure increase, octahedral and bending δ(ОН) vibrations exhibit linear positive pressure shift, whereas wavenumbers of the ОН-stretching modes show inverse pressure dependence.

Original languageEnglish
Pages (from-to)495-510
Number of pages16
JournalHigh Pressure Research
Volume40
Issue number4
DOIs
Publication statusPublished - 1 Oct 2020

Keywords

  • 3.65 Å-phase
  • dense hydrous magnesium silicates
  • high pressure
  • Raman spectra
  • six-coordinated silicon
  • SYSTEM
  • DENSE
  • STABILITY
  • BEHAVIOR
  • VIBRATIONAL-SPECTRA
  • CRYSTAL-CHEMISTRY
  • 3.65 angstrom-phase
  • MGSIO3 PEROVSKITE
  • THAUMASITE
  • HYDROUS MAGNESIUM SILICATES
  • WATER

Fingerprint

Dive into the research topics of 'Raman study of 3.65 Å-phase MgSi(OH)<sub>6</sub> under high pressure and the bands assignment'. Together they form a unique fingerprint.

Cite this