Bridgmanite

MgSiO3

third-order Birch-Murnaghan · Original · 1993

Why this differs from similar rows?

Ab initio calculation for the Pbnm (orthorhombic) phase (K0=259, K'0=3.9); sibling row is for a distinct hypothetical cubic phase of the same composition (K0=258, K'0=4.0).

V₀

—

Unknown basis

K₀

259

GPa

Unknown

K′

3.900

dimensionless

Volume (V₀)

Value	Unit	Basis	Z
—	—	Unknown basis	—

Reported value and unit are preserved as extracted. Z (formula units per cell) is not stored yet, so molar ↔ Å³/f.u. conversion is not applied automatically.

Composition

Oxide	Molar
MgO	1
SiO2	1

Formula: MgSiO3

Conditions & method

T_ref: —
P_ref: —
Structure: orthorhombic perovskite (Pbnm/Pnma)
Method: molecular dynamics
ab initio (LDA pseudopotential plane-wave) constant-pressure molecular dynamics / structural optimization, static (zero temperature)
Sample: ab initio calculated Pbnm phase

Source

Paper: Ab initiomolecular dynamics with variable cell shape: Application toMgSiO3
Authors: Renata M. Wentzcovitch; José Luı́s Martins; G. D. Price
DOI: 10.1103/physrevlett.70.3947
Year: 1993
Journal: Physical Review Letters
Origin: Original (measured or fitted in the source paper)

Evidence from the paper

A third-order fit to the Birch-Murnaghan's equation of state [20], of the calculated volume versus pressure relation produces similar bulk moduli for both phases. These and their pressure derivatives are K0 = 259 and 258 GPa and K'0 = 3.9 and 4.0 for the Pbnm and cubic phases, respectively.

Additional notes

zero pressure lattice parameters calc Angstrom

{
  "a": 4.711,
  "b": 4.88,
  "c": 6.851
}

note

No explicit V0 value is quoted; only zero-pressure lattice parameters are tabulated (Table I). Interlaboratory experimental K0 range for Pbnm quoted as 243 [27] to 266 GPa [20].