Bridgmanite
Fe0.5Mg0.5Al0.5Si0.5O3
second-order Birch-Murnaghan · Original · 2023
Why this differs from similar rows?
Values for the distorted-perovskite phase, stable above 8+/-2 GPa; sibling row 1293 is the lower-pressure LiNbO3-type structure.
V₀
171.2
ų
Unit cell
K₀
221
GPa
Isothermal
K′
4
dimensionless
Volume (V₀)
| Value | Unit | Basis | Z |
|---|---|---|---|
| 171.2 | 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 | 0.5 |
| FeO | 0.08 |
| Fe2O3 | 0.21 |
| Al2O3 | 0.25 |
| SiO2 | 0.5 |
Formula: Fe0.5Mg0.5Al0.5Si0.5O3
Conditions & method
- Tref
- —
- Pref
- —
- Structure
- orthorhombic perovskite (Pbnm/Pnma)
- Method
- experiment (XRD / DAC / multianvil compression)single-crystal X-ray diffraction in diamond anvil cell (ID15B, ESRF)
- Sample
- single crystal synthesized in Kawai-type multi-anvil press
Source
- Paper
- Crystal chemistry and compressibility of Fe0.5Mg0.5Al0.5Si0.5O3 and FeMg0.5Si0.…
- Authors
- Iuliia Koemets; Biao Wang; Egor Koemets; Takayuki Ishii; Zhaodong Liu; Catherine McCammon; Artem Chanyshev; Tomo Katsura; Michael Hanfland; Alexander Chumakov; Leonid Dubrovinsky
- DOI
- 10.3389/fchem.2023.1258389
- Year
- 2023
- Journal
- Frontiers in Chemistry
- Origin
- Original (measured or fitted in the source paper)
Evidence from the paper
Above 8 ± 2 GPa, Fe0.5Mg0.5Si0.5Al0.5O3 adopts a distorted perovskite structure with a smaller volume but a higher bulk modulus (V0 = 171.2 ± 0.2 Å3; K0 = 221 ± 3 GPa). ... The fitting of pressure–volume data for perovskite-structured phases with the second-order Birch–Murnaghan equation of state (BM2–EoS) resulted in a bulk modulus of 212(3) GPa for Fe0.5Mg0.5Al0.5Si0.5O3.
Additional notes
Kp note
K′ = 4 is implied by the second-order Birch–Murnaghan EoS truncation; not explicitly stated as a number in the text
discrepancy note
Figure 4 caption reports K0 = 221 ± 3 GPa while main text (Section 3.4) reports 212(3) GPa for the same phase; both values reported verbatim in evidence
polyhedral bulk moduli
A-sites KA0 = 216 ± 6 GPa; B-sites KB0 = 238 ± 7 (GPa)