RbMg6CrO8
High-Entropy Materials HEAMP-ID: mp-1033645 · Space group: P4/mmm (#123)
Basic Information
Formula
RbMg6CrO8
MP-ID
mp-1033645
Elements
4
Sites
16
Density
3.8071
g/cm³
Volume
179.39
ų
Cell a
8.8552
Å
Cell b
4.5010
Å
Cell c
4.5010
Å
α Angle
90.00
°
β Angle
90.00
°
γ Angle
90.00
°
Space Group
P4/mmm
Point Group
4/mmm
Crystal System
Tetragonal
Bravais Lattice
tP
Stability
No
Packing Fraction
-
X-ray Diffraction
Diffraction Pattern
X-axis: 2θ (°); Y-axis: relative intensity; Cu Kα ; λ=1.5418 Å
Diffraction Peaks (Top 24)
| 2θ | d (Å) | I | hkl |
|---|---|---|---|
| 9.99 | 8.8552 | 3.0 | (1,0,0) |
| 19.72 | 4.5010 | 28.0 | (0,1,0) |
| 20.05 | 4.4276 | 14.3 | (2,0,0) |
| 22.15 | 4.0124 | 3.4 | (1,1,0) |
| 28.04 | 3.1827 | 11.9 | (0,1,1) |
| 28.27 | 3.1564 | 24.5 | (2,1,0) |
| 29.83 | 2.9951 | 2.1 | (1,1,1) |
| 30.28 | 2.9517 | 2.3 | (3,0,0) |
| 34.71 | 2.5843 | 44.8 | (2,1,1) |
| 36.40 | 2.4683 | 3.5 | (3,1,0) |
| 40.07 | 2.2505 | 100.0 | (0,2,0) |
| 40.76 | 2.2138 | 45.3 | (4,0,0) |
| 41.74 | 2.1642 | 1.7 | (3,1,1) |
| 45.04 | 2.0129 | 6.1 | (0,2,1) |
| 45.20 | 2.0062 | 6.4 | (2,2,0) |
| 45.67 | 1.9865 | 4.8 | (4,1,0) |
| 46.25 | 1.9628 | 1.2 | (1,2,1) |
| 49.76 | 1.8324 | 9.4 | (2,2,1) |
| 50.20 | 1.8174 | 3.7 | (4,1,1) |
| 51.03 | 1.7897 | 2.0 | (3,2,0) |
| 55.24 | 1.6630 | 2.1 | (3,2,1) |
| 57.95 | 1.5913 | 29.5 | (0,2,2) |
| 58.48 | 1.5782 | 54.9 | (4,2,0) |
| 61.84 | 1.5003 | 1.1 | (0,3,0) |
Energy Properties
Formation Energy/atom
-2.38062
eV/atom
Energy/atom
-6.13062
eV/atom
Energy above Hull
0.3981
eV/atom
Uncorrected Energy
-5.6622
eV/atom
Volume/atom
11.21
ų
c/a Ratio
0.5083
Electronic Properties
Metallic
Metal
Band Gap
0
eV
Direct Gap
No
CBM
N/A
eV
Magnetic Properties
Magnetic
Yes
Total Mag. Moment
4.1106
μB
Mag. Ordering
FM
Mag. Sites
2
Magnetization/Volume
0.022910
μB/ų
Elastic Properties
Elastic data not available
Feature Analysis
Composition Overview
Element Composition (atomic fraction)
Composition Info
Major / Matrix Element
O · 0.500
Element Family
Metalloid-Nonmetal
Solute Fraction
0.500
Interstitial Fraction
0.000
High-Entropy Alloy Features
Composite Radar (normalized)
Element-Class Share
Mix Entropy ΔS/R
1.0610
HEA criterion (>1.0 = high entropy)
Mix Entropy ΔS
8.8208
J/mol·K
Ω Parameter
4.8471
Ω > 1.1 favors solid solution
Atomic Size Mismatch δr
50.019%
δr < 6.6% favors single-phase solid solution
Electronegativity Diff Δχ
1.0842
smaller = more stable mixing
VEC
3.188
valence electron concentration, affects phase stability
Mix Enthalpy ΔH_mix
-0.963
kJ/mol; negative = exothermic mixing
Entropy Norm
0.7653
SS Former
0
Phase Tendency
IM
Related Tasks
Citation & References
Materials Project Page
https://materialsproject.org/materials/mp-1033645
Reference Citation
The crystal structure and related material properties of RbMg6CrO8 were obtained from the Materials Project database (MP-ID: mp-1033645, database version v2026.04.13).
Literature Citation
Horton, M.K., Huck, P., Yang, R.X. et al. Accelerated data-driven materials science with the Materials Project. Nat. Mater. 24, 1522–1532 (2025). https://doi.org/10.1038/s41563-025-02272-0
3D Crystal Structure Rendering
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Raw CIF Data
# generated using pymatgen
data_RbMg6CrO8
_symmetry_space_group_name_H-M 'P 1'
_cell_length_a 8.85519898
_cell_length_b 4.50094676
_cell_length_c 4.50094676
_cell_angle_alpha 90.00000000
_cell_angle_beta 90.00000000
_cell_angle_gamma 90.00000000
_symmetry_Int_Tables_number 1
_chemical_formula_structural RbMg6CrO8
_chemical_formula_sum 'Rb1 Mg6 Cr1 O8'
_cell_volume 179.39324102
_cell_formula_units_Z 1
loop_
_symmetry_equiv_pos_site_id
_symmetry_equiv_pos_as_xyz
1 'x, y, z'
loop_
_atom_site_type_symbol
_atom_site_label
_atom_site_symmetry_multiplicity
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_occupancy
Rb Rb0 1 0.00000000 0.00000000 0.00000000 1.0
Mg Mg1 1 0.00000000 0.50000000 0.50000000 1.0
Mg Mg2 1 0.50000000 0.50000000 0.50000000 1.0
Mg Mg3 1 0.25522347 0.00000000 0.50000000 1.0
Mg Mg4 1 0.74477653 0.00000000 0.50000000 1.0
Mg Mg5 1 0.25522347 0.50000000 0.00000000 1.0
Mg Mg6 1 0.74477653 0.50000000 0.00000000 1.0
Cr Cr7 1 0.50000000 0.00000000 0.00000000 1.0
O O8 1 0.27958882 0.00000000 0.00000000 1.0
O O9 1 0.72041118 0.00000000 0.00000000 1.0
O O10 1 0.25206319 0.50000000 0.50000000 1.0
O O11 1 0.74793681 0.50000000 0.50000000 1.0
O O12 1 0.00000000 0.00000000 0.50000000 1.0
O O13 1 0.50000000 0.00000000 0.50000000 1.0
O O14 1 0.00000000 0.50000000 0.00000000 1.0
O O15 1 0.50000000 0.50000000 0.00000000 1.0
