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FeCoAs

High-Entropy Materials HEA Traditional Materials TRA

MP-ID: mp-675526 · Space group: Pmm2 (#25)

Basic Information

Formula
FeCoAs
MP-ID
mp-675526
Elements
3
Sites
18
Density
8.4402
g/cm³
Volume
223.93
ų
Cell a
3.5899
Å
Cell b
6.0220
Å
Cell c
10.3584
Å
α Angle
90.00
°
β Angle
90.00
°
γ Angle
90.00
°
Space Group
Pmm2
Point Group
mm2
Crystal System
Orthorhombic
Bravais Lattice
Orthorhombic P
Stability
No
Packing Fraction
0.5240

X-ray Diffraction

Diffraction Pattern
X-axis: 2θ (°); Y-axis: relative intensity; CuKa ; λ=1.5406 Å
Diffraction Peaks (Top 24)
2θd (Å)Ihkl
17.03 5.2062 1.8 (0,1,1)
17.12 5.1792 1.2 (0,0,2)
24.80 3.5899 7.8 (1,0,0)
29.67 3.0110 6.1 (0,2,0)
29.83 2.9954 10.4 (0,1,3)
30.24 2.9554 8.7 (1,1,1)
30.29 2.9504 5.0 (1,0,2)
34.45 2.6031 1.9 (0,2,2)
39.04 2.3070 45.1 (1,2,0)
39.17 2.2999 95.3 (1,1,3)
42.92 2.1074 100.0 (1,2,2)
43.07 2.1002 52.2 (1,0,4)
46.06 1.9707 19.4 (0,3,1)
46.24 1.9634 17.4 (0,2,4)
46.35 1.9590 16.1 (0,1,5)
50.87 1.7949 53.0 (2,0,0)
52.75 1.7354 41.0 (0,3,3)
53.01 1.7275 22.1 (1,3,1)
53.04 1.7264 21.5 (0,0,6)
53.17 1.7226 23.9 (1,2,4)
53.27 1.7196 19.3 (1,1,5)
59.13 1.5624 1.6 (1,3,3)
60.00 1.5418 1.9 (2,2,0)
60.09 1.5397 3.2 (2,1,3)
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Energy Properties

Formation Energy/atom
-0.12042
eV/atom
Energy/atom
-6.87828
eV/atom
Energy above Hull
0.0678
eV/atom
Uncorrected Energy
-6.8783
eV/atom
Volume/atom
12.44
ų
c/a Ratio
-

Electronic Properties

Metallic
Metal
Band Gap
0
eV
Direct Gap
No
CBM
N/A
eV

Magnetic Properties

Magnetic
Yes
Total Mag. Moment
13.0433
μB
Mag. Ordering
FM
Mag. Sites
12
Magnetization/Volume
0.058250
μB/ų

Elastic Properties

Elastic data not available

Feature Analysis

Composition Overview

Element Composition (atomic fraction)
Composition Info
Major / Matrix Element
Fe · 0.333
Element Family
3d-TM
Solute Fraction
0.667
Interstitial Fraction
0.000

High-Entropy Alloy Features

Composite Radar (normalized)
Element-Class Share
Mix Entropy ΔS/R
1.0986
HEA criterion (>1.0 = high entropy)
Mix Entropy ΔS
9.1339
J/mol·K
Ω Parameter
31.9845
Ω > 1.1 favors solid solution
Atomic Size Mismatch δr
4.071%
δr < 6.6% favors single-phase solid solution
Electronegativity Diff Δχ
0.1546
smaller = more stable mixing
VEC
6.667
valence electron concentration, affects phase stability
Mix Enthalpy ΔH_mix
-0.444
kJ/mol; negative = exothermic mixing
Entropy Norm
1.0000
SS Former
1
Phase Tendency
SS

Traditional Material Features

ROM Blended-Feature Radar
Rating & Classification
Tier
C
Score
0.509
Family
Fe-rich Multi-Component
Matrix Element
Fe · 0.333

Related Tasks

Related computation task IDs (2)

Citation & References

Materials Project Page
https://materialsproject.org/materials/mp-675526
Reference Citation

The crystal structure and related material properties of FeCoAs were obtained from the Materials Project database (MP-ID: mp-675526, 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

BibTeX
@article{Horton2025,
  author  = {Horton, Matthew K. and Huck, Patrick and Yang, Ruo Xi and Munro, Jason M. and Dwaraknath, Shyam and Ganose, Alex M. and Kingsbury, Ryan S. and Wen, Mingjian and Shen, Jimmy X. and Mathis, Tyler S. and Kaplan, Aaron D. and Berket, Karlo and Riebesell, Janosh and George, Janine and Rosen, Andrew S. and Spotte-Smith, Evan W. C. and McDermott, Matthew J. and Cohen, Orion A. and Dunn, Alex and Kuner, Matthew C. and Rignanese, Gian-Marco and Petretto, Guido and Waroquiers, David and Griffin, Sinead M. and Neaton, Jeffrey B. and Chrzan, Daryl C. and Asta, Mark and Hautier, Geoffroy and Cholia, Shreyas and Ceder, Gerbrand and Ong, Shyue Ping and Jain, Anubhav and Persson, Kristin A.},
  title   = {Accelerated data-driven materials science with the Materials Project},
  journal = {Nature Materials},
  year    = {2025},
  volume  = {24},
  number  = {10},
  pages   = {1522--1532},
  month   = {oct},
  doi     = {10.1038/s41563-025-02272-0},
  issn    = {1476-4660},
  url     = {https://doi.org/10.1038/s41563-025-02272-0},
  abstract = {The Materials Project was launched formally in 2011 to drive materials discovery forwards through high-throughput computation and open data. More than a decade later, the Materials Project has become an indispensable tool used by more than 600,000 materials researchers around the world. This Perspective describes how the Materials Project, as a data platform and a software ecosystem, has helped to shape research in data-driven materials science. We cover how sustainable software and computational methods have accelerated materials design while becoming more open source and collaborative in nature. Next, we present cases where the Materials Project was used to understand and discover functional materials. We then describe our efforts to meet the needs of an expanding user base, through technical infrastructure updates ranging from data architecture and cloud resources to interactive web applications. Finally, we discuss opportunities to better aid the research community, with the vision that more accessible and easy-to-understand materials data will result in democratized materials knowledge and an increasingly collaborative community.}
}

3D Crystal Structure Rendering

Loading 3D structure…

Style: Ball & Stick
Raw CIF Data
# generated using pymatgen
data_FeCoAs
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.58986700
_cell_length_b   6.02202600
_cell_length_c   10.35843300
_cell_angle_alpha   90.00000000
_cell_angle_beta   90.00000000
_cell_angle_gamma   90.00000000
_symmetry_Int_Tables_number   1
_chemical_formula_structural   FeCoAs
_chemical_formula_sum   'Fe6 Co6 As6'
_cell_volume   223.93142634
_cell_formula_units_Z   6
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
  Fe  Fe0  1  0.00000000  0.29524100  0.20167500  1.0
  Fe  Fe1  1  0.00000000  0.29524100  0.79832500  1.0
  Fe  Fe2  1  0.00000000  0.90546200  0.00000000  1.0
  Fe  Fe3  1  0.00000000  0.79646800  0.29951000  1.0
  Fe  Fe4  1  0.00000000  0.79646800  0.70049000  1.0
  Fe  Fe5  1  0.50000000  0.74519200  0.50000000  1.0
  Co  Co6  1  0.50000000  0.62604900  0.12936200  1.0
  Co  Co7  1  0.00000000  0.40166500  0.50000000  1.0
  Co  Co8  1  0.50000000  0.24541600  0.00000000  1.0
  Co  Co9  1  0.50000000  0.12362000  0.37148000  1.0
  Co  Co10  1  0.50000000  0.12362000  0.62852000  1.0
  Co  Co11  1  0.50000000  0.62604900  0.87063800  1.0
  As  As12  1  0.00000000  0.00085700  0.50000000  1.0
  As  As13  1  0.50000000  0.49533900  0.33540600  1.0
  As  As14  1  0.50000000  0.99931700  0.83429500  1.0
  As  As15  1  0.50000000  0.99931700  0.16570500  1.0
  As  As16  1  0.00000000  0.50165400  0.00000000  1.0
  As  As17  1  0.50000000  0.49533900  0.66459400  1.0
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