KMg6CO8
High-Entropy Materials HEAMP-ID: mp-1030927 · Space group: P4/mmm (#123)
Basic Information
Formula
KMg6CO8
MP-ID
mp-1030927
Elements
4
Sites
16
Density
3.2287
g/cm³
Volume
167.12
ų
Cell a
8.8131
Å
Cell b
4.3546
Å
Cell c
4.3546
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 17)
| 2θ | d (Å) | I | hkl |
|---|---|---|---|
| 20.39 | 4.3546 | 5.2 | (0,1,0) |
| 22.78 | 3.9040 | 5.0 | (1,1,0) |
| 28.82 | 3.0974 | 4.9 | (2,1,0) |
| 35.57 | 2.5240 | 15.5 | (2,1,1) |
| 36.91 | 2.4353 | 5.5 | (3,1,0) |
| 40.96 | 2.2033 | 50.1 | (4,0,0) |
| 41.47 | 2.1773 | 100.0 | (0,2,0) |
| 46.64 | 1.9474 | 1.1 | (0,2,1) |
| 47.83 | 1.9016 | 1.4 | (1,2,1) |
| 51.29 | 1.7812 | 1.8 | (2,2,1) |
| 56.71 | 1.6232 | 2.7 | (3,2,1) |
| 59.71 | 1.5487 | 55.0 | (4,2,0) |
| 60.10 | 1.5396 | 27.8 | (0,2,2) |
| 71.11 | 1.3257 | 3.9 | (6,1,1) |
| 71.82 | 1.3144 | 6.5 | (2,3,1) |
| 75.31 | 1.2620 | 24.5 | (4,2,2) |
| 88.82 | 1.1016 | 3.4 | (8,0,0) |
Energy Properties
Formation Energy/atom
-1.94571
eV/atom
Energy/atom
-5.67876
eV/atom
Energy above Hull
0.8249
eV/atom
Uncorrected Energy
-5.3353
eV/atom
Volume/atom
10.44
ų
c/a Ratio
0.4941
Electronic Properties
Metallic
Metal
Band Gap
0
eV
Direct Gap
No
CBM
N/A
eV
Magnetic Properties
Magnetic
Yes
Total Mag. Moment
0.9682
μB
Mag. Ordering
FM
Mag. Sites
1
Magnetization/Volume
0.005790
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
0.063
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
1.6557
Ω > 1.1 favors solid solution
Atomic Size Mismatch δr
50.534%
δr < 6.6% favors single-phase solid solution
Electronegativity Diff Δχ
1.0692
smaller = more stable mixing
VEC
3.063
valence electron concentration, affects phase stability
Mix Enthalpy ΔH_mix
-3.375
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-1030927
Reference Citation
The crystal structure and related material properties of KMg6CO8 were obtained from the Materials Project database (MP-ID: mp-1030927, 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_KMg6CO8
_symmetry_space_group_name_H-M 'P 1'
_cell_length_a 8.81307571
_cell_length_b 4.35456722
_cell_length_c 4.35456722
_cell_angle_alpha 90.00000000
_cell_angle_beta 90.00000000
_cell_angle_gamma 90.00000000
_symmetry_Int_Tables_number 1
_chemical_formula_structural KMg6CO8
_chemical_formula_sum 'K1 Mg6 C1 O8'
_cell_volume 167.11579488
_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
K K0 1 -0.00000000 0.00000000 -0.00000000 1.0
Mg Mg1 1 0.50000000 0.00000000 -0.00000000 1.0
Mg Mg2 1 0.50000000 0.50000000 0.50000000 1.0
Mg Mg3 1 0.25421443 0.00000000 0.50000000 1.0
Mg Mg4 1 0.74578557 0.00000000 0.50000000 1.0
Mg Mg5 1 0.25421443 0.50000000 0.00000000 1.0
Mg Mg6 1 0.74578557 0.50000000 -0.00000000 1.0
C C7 1 -0.00000000 0.50000000 0.50000000 1.0
O O8 1 0.27355739 0.00000000 0.00000000 1.0
O O9 1 0.72644261 -0.00000000 -0.00000000 1.0
O O10 1 0.24590703 0.50000000 0.50000000 1.0
O O11 1 0.75409297 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
