Post-perovskite
MgGeO3
Birch-Murnaghan (order unspecified) · Original · 2005
Why this differs from similar rows?
K'0 fixed to 4 in the fit; sibling row fits K'0 freely (3.5) to the same decompression data, giving a different K0/V0.
V₀
183.1
ų
Unit cell
K₀
192
GPa
Isothermal
K′
4
dimensionless
Volume (V₀)
| Value | Unit | Basis | Z |
|---|---|---|---|
| 183.1 | 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 |
|---|---|
| MgO | 1 |
| GeO2 | 1 |
Formula: MgGeO3
Conditions & method
- Tref
- 300 K
- Pref
- —
- Structure
- post-perovskite (CaIrO3-type, Cmcm)
- Method
- experiment (XRD / DAC / multianvil compression)synchrotron X-ray diffraction in laser-heated diamond-anvil cell, P-V data at 300 K during decompression; Pt pressure standard (Holmes et al. 1989)
- Sample
- MgGeO3 post-perovskite synthesized in LHDAC, decompression data 79-6 GPa
Source
- Paper
- Stability and equation of state of MgGeO 3 post-perovskite phase
- Authors
- Kei Hirose; Katsuyuki Kawamura; Yasuo Ohishi; Shigehiko Tateno; Nagayoshi Sata
- DOI
- 10.2138/am.2005.1702
- Year
- 2005
- Journal
- American Mineralogist
- Origin
- Original (measured or fitted in the source paper)
Evidence from the paper
"When K'0 was fixed at 4, we obtained K0 = 192(±5) GPa and V0 = 183.1(±0.8) Å3." Abstract: "The bulk modulus was determined to be K0 = 192(±5) GPa with a fixed pressure derivative of the bulk modulus, K', of 4."
Additional notes
Z
4
pressure range
79 to 6 GPa at 300 K
note
MgGeO3 post-perovskite used as low-pressure analogue for MgSiO3 post-perovskite of the lowermost mantle (D'' layer)
assumed ambient cell parameters for normalization
a0 = 2.800, b0 = 9.390, c0 = 6.965 Å (Fig. 3, assumed)