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Post-stishovite (CaCl₂-type)
SiO2
second-order Birch-Murnaghan · Original · 2003
V₀
46.31
ų
Unit cell
K₀
334
GPa
Unknown
K′
4
dimensionless
Volume (V₀)
| Value | Unit | Basis | Z |
|---|---|---|---|
| 46.31 | ų | Unit cell | — |
Reported value and unit are preserved as extracted. Z (formula units per cell) is not stored yet, so molar ↔ ų/f.u. conversion is not applied automatically.
Composition
| Oxide | Molar |
|---|---|
| SiO2 | 1 |
Formula: SiO2
Conditions & method
- Tref
- —
- Pref
- —
- Structure
- CaCl2-type SiO2
- Method
- experiment (XRD / DAC / multianvil compression)powder X-ray diffraction in diamond anvil cell, laser annealing, least-squares fit (EosFit v5.2)
- Sample
- combined data sets up to ~135 GPa, pressures above ~60 GPa from Pt EoS (Holmes et al. 1989)
Source
- Paper
- Equation of state of stishovite to lower mantle pressures
- Authors
- D. Andrault; R. J. Angel; J. L. Mosenfelder; Tristan Le Bihan
- DOI
- 10.2138/am-2003-2-307
- Year
- 2003
- Journal
- American Mineralogist
- Origin
- Original (measured or fitted in the source paper)
Evidence from the paper
We obtain K0 = 334(7) GPa and V0 = 46.31(15) Å3 for the CaCl2 phase, with a first pressure derivative fixed to K'0 = 4. We refined a CaCl2 form V0 value slightly lower than that of stishovite.
Additional notes
note
CaCl2 form observed above ~60 GPa; f-F plot indicates K'0 very close to 4 and the CaCl2 form slightly more compressible than stishovite above the transition