UFeAs2
High-Entropy Materials HEA Traditional Materials TRAMP-ID: mp-1087511 · Space group: P4/nmm (#129)
Basic Information
Formula
UFeAs2
MP-ID
mp-1087511
Elements
3
Sites
8
Density
9.8076
g/cm³
Volume
150.25
ų
Cell a
3.9652
Å
Cell b
3.9652
Å
Cell c
9.5563
Å
α Angle
90.00
°
β Angle
90.00
°
γ Angle
90.00
°
Space Group
P4/nmm
Point Group
4/mmm
Crystal System
Tetragonal
Bravais Lattice
tP
Stability
Yes
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 |
|---|---|---|---|
| 18.57 | 4.7782 | 12.3 | (0,0,2) |
| 24.30 | 3.6625 | 47.1 | (1,0,1) |
| 29.27 | 3.0514 | 13.4 | (1,0,2) |
| 31.92 | 2.8038 | 13.3 | (1,1,0) |
| 33.30 | 2.6904 | 1.4 | (1,1,1) |
| 36.17 | 2.4834 | 35.1 | (1,0,3) |
| 37.18 | 2.4182 | 100.0 | (1,1,2) |
| 37.65 | 2.3891 | 14.5 | (0,0,4) |
| 44.26 | 2.0464 | 7.2 | (1,0,4) |
| 45.76 | 1.9826 | 34.4 | (2,0,0) |
| 49.79 | 1.8312 | 4.5 | (2,0,2) |
| 52.48 | 1.7435 | 12.8 | (2,1,1) |
| 53.20 | 1.7217 | 18.1 | (1,0,5) |
| 55.25 | 1.6625 | 4.5 | (2,1,2) |
| 59.68 | 1.5494 | 17.1 | (2,1,3) |
| 60.70 | 1.5257 | 14.5 | (2,0,4) |
| 62.88 | 1.4780 | 1.3 | (1,0,6) |
| 65.56 | 1.4239 | 4.5 | (2,1,4) |
| 66.72 | 1.4019 | 11.2 | (2,2,0) |
| 67.65 | 1.3849 | 7.6 | (1,1,6) |
| 69.93 | 1.3452 | 1.9 | (2,2,2) |
| 72.15 | 1.3093 | 2.7 | (3,0,1) |
| 72.75 | 1.3000 | 14.8 | (2,1,5) |
| 73.34 | 1.2908 | 5.8 | (1,0,7) |
Energy Properties
Formation Energy/atom
-0.51752
eV/atom
Energy/atom
-7.79294
eV/atom
Energy above Hull
0.0000
eV/atom
Uncorrected Energy
-31.6453
eV/atom
Volume/atom
18.78
ų
c/a Ratio
2.4100
Electronic Properties
Metallic
Metal
Band Gap
0
eV
Direct Gap
No
CBM
N/A
eV
Magnetic Properties
Magnetic
Yes
Total Mag. Moment
1.0131
μB
Mag. Ordering
Unknown
Mag. Sites
0
Magnetization/Volume
0.006740
μB/ų
Elastic Properties
Elastic data not available
Feature Analysis
Composition Overview
Element Composition (atomic fraction)
Composition Info
Major / Matrix Element
As · 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
1.0397
HEA criterion (>1.0 = high entropy)
Mix Entropy ΔS
8.6442
J/mol·K
Ω Parameter
0.0000
Ω > 1.1 favors solid solution
Atomic Size Mismatch δr
18.684%
δr < 6.6% favors single-phase solid solution
Electronegativity Diff Δχ
0.3286
smaller = more stable mixing
VEC
4.667
valence electron concentration, affects phase stability
Mix Enthalpy ΔH_mix
0.000
kJ/mol; negative = exothermic mixing
Entropy Norm
0.9464
SS Former
0
Phase Tendency
IM
Traditional Material Features
ROM Blended-Feature Radar
Rating & Classification
Tier
C
Score
0.429
Family
As-rich Multi-Component
Matrix Element
As · 0.500
Related Tasks
Citation & References
Materials Project Page
https://materialsproject.org/materials/mp-1087511
Reference Citation
The crystal structure and related material properties of UFeAs2 were obtained from the Materials Project database (MP-ID: mp-1087511, 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_UFeAs2
_symmetry_space_group_name_H-M 'P 1'
_cell_length_a 3.96521325
_cell_length_b 3.96521325
_cell_length_c 9.55632733
_cell_angle_alpha 90.00000000
_cell_angle_beta 90.00000000
_cell_angle_gamma 90.00000000
_symmetry_Int_Tables_number 1
_chemical_formula_structural UFeAs2
_chemical_formula_sum 'U2 Fe2 As4'
_cell_volume 150.25333301
_cell_formula_units_Z 2
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
U U0 1 -0.00000000 0.50000000 0.76287515 1.0
U U1 1 0.50000000 -0.00000000 0.23712485 1.0
Fe Fe2 1 0.50000000 0.50000000 0.50000000 1.0
Fe Fe3 1 0.00000000 -0.00000000 0.50000000 1.0
As As4 1 0.50000000 0.50000000 -0.00000000 1.0
As As5 1 -0.00000000 -0.00000000 -0.00000000 1.0
As As6 1 0.00000000 0.50000000 0.33709983 1.0
As As7 1 0.50000000 0.00000000 0.66290017 1.0
