Phase Egg
AlSiO3(OH)
third-order Birch-Murnaghan · Original · 2018
Why this differs from similar rows?
DFT result for the high-pressure (hiP) phase Egg structure above the ~15 GPa proton-transfer transition (metastable extrapolation to zero pressure); sibling row is the loP structure.
V₀
207.74
ų
Unit cell
K₀
222.800
GPa
Unknown
K′
4.440
dimensionless
Volume (V₀)
| Value | Unit | Basis | Z |
|---|---|---|---|
| 207.74 | 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 |
|---|---|
| Al2O3 | 0.5 |
| SiO2 | 1 |
| H2O | 0.5 |
Formula: AlSiO3(OH)
Conditions & method
- Tref
- —
- Pref
- —
- Structure
- other / unspecified
- Method
- first-principles DFT / ab initiofirst-principles DFT (GGA, PAW, VASP, static)
- Sample
- first-principles simulated ordered unit cell
Source
- Paper
- Anomalous elastic behavior of phase Egg, AlSiO3(OH), at high pressures
- Authors
- —
- DOI
- 10.2138/am-2018-6694
- Year
- 2018
- Journal
- American Mineralogist
- Origin
- Original (measured or fitted in the source paper)
Evidence from the paper
The bulk modulus at zero-pressure (K0^hiP), unit-cell volume at zero pressure (V0^hiP) and the pressure derivative of zero-pressure bulk modulus (K'0^hiP) for phase Egg (hiP) at pressures above the transfer of proton are, 222.8 (±0.2) GPa, 207.74 (±0.01) ų, and 4.44 (±0.02) respectively.
Additional notes
static conditions
first principles simulations are at static conditions (0 K)
linear moduli GPa
Ka^hiP = 815.6 (±2.8), Kb^hiP = 507.9 (±0.7), Kc*^hiP = 789.6 (±1.1)
note
values from metastable extension of high-pressure structure to zero pressure; zero-pressure volume of loP is ~1.2 % larger and its K0 ~35.5 % softer than hiP
proton transfer pressure
~15 GPa