Pa2AlSi2
High-Entropy Materials HEA Traditional Materials TRAMP-ID: mp-3249311 · Space group: Immm (#71)
Basic Information
Formula
Pa2AlSi2
MP-ID
mp-3249311
Elements
3
Sites
5
Density
9.1561
g/cm³
Volume
98.88
ų
Cell a
5.6151
Å
Cell b
5.6151
Å
Cell c
5.6151
Å
α Angle
138.94
°
β Angle
119.36
°
γ Angle
75.85
°
Space Group
Immm
Point Group
mmm
Crystal System
Orthorhombic
Bravais Lattice
oI
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 |
|---|---|---|---|
| 18.58 | 4.7750 | 6.3 | (1,0,0) |
| 18.58 | 4.7750 | 6.3 | (0,1,-1) |
| 20.05 | 4.4291 | 94.0 | (1,1,-1) |
| 24.74 | 3.5984 | 3.6 | (1,0,-1) |
| 27.58 | 3.2343 | 69.5 | (0,0,1) |
| 27.58 | 3.2343 | 69.5 | (1,-1,0) |
| 31.56 | 2.8346 | 54.5 | (1,-1,1) |
| 34.24 | 2.6188 | 17.2 | (2,1,-1) |
| 34.24 | 2.6188 | 17.2 | (1,2,-2) |
| 34.33 | 2.6120 | 100.0 | (1,1,-2) |
| 34.33 | 2.6120 | 100.0 | (2,0,-1) |
| 37.68 | 2.3875 | 71.5 | (2,0,0) |
| 38.09 | 2.3624 | 29.4 | (2,1,-2) |
| 40.51 | 2.2267 | 8.3 | (1,0,1) |
| 40.51 | 2.2267 | 8.3 | (2,-1,0) |
| 40.74 | 2.2146 | 23.7 | (2,2,-2) |
| 46.10 | 1.9690 | 30.4 | (1,-1,-1) |
| 49.91 | 1.8273 | 19.1 | (2,2,-3) |
| 49.91 | 1.8273 | 6.4 | (1,3,-2) |
| 50.11 | 1.8203 | 1.0 | (1,0,-2) |
| 50.11 | 1.8203 | 1.0 | (2,-1,-1) |
| 50.28 | 1.8148 | 5.5 | (2,1,0) |
| 50.28 | 1.8148 | 5.5 | (3,0,-1) |
| 50.74 | 1.7992 | 18.2 | (2,0,-2) |
Energy Properties
Formation Energy/atom
-0.48421
eV/atom
Energy/atom
-36.08254
eV/atom
Energy above Hull
0.0000
eV/atom
Uncorrected Energy
-36.0825
eV/atom
Volume/atom
19.78
ų
c/a Ratio
1.0000
Electronic Properties
Metallic
Metal
Band Gap
0
eV
Direct Gap
No
CBM
N/A
eV
Magnetic Properties
Magnetic
No
Total Mag. Moment
0.0001
μB
Mag. Ordering
NM
Mag. Sites
0
Magnetization/Volume
0.000000
μB/ų
Elastic Properties
Elastic data not available
Feature Analysis
Composition Overview
Element Composition (atomic fraction)
Composition Info
Major / Matrix Element
Pa · 0.400
Element Family
Actinide
Solute Fraction
0.600
Interstitial Fraction
0.400
High-Entropy Alloy Features
Composite Radar (normalized)
Element-Class Share
Mix Entropy ΔS/R
1.0549
HEA criterion (>1.0 = high entropy)
Mix Entropy ΔS
8.7706
J/mol·K
Ω Parameter
5.4744
Ω > 1.1 favors solid solution
Atomic Size Mismatch δr
19.172%
δr < 6.6% favors single-phase solid solution
Electronegativity Diff Δχ
0.1825
smaller = more stable mixing
VEC
3.667
valence electron concentration, affects phase stability
Mix Enthalpy ΔH_mix
-2.560
kJ/mol; negative = exothermic mixing
Entropy Norm
0.9602
SS Former
0
Phase Tendency
IM
Traditional Material Features
ROM Blended-Feature Radar
Rating & Classification
Tier
B
Score
0.468
Family
Pa-rich Multi-Component
Matrix Element
Pa · 0.400
Related Tasks
Related computation task IDs (1)
Citation & References
Materials Project Page
https://materialsproject.org/materials/mp-3249311
Reference Citation
The crystal structure and related material properties of Pa2AlSi2 were obtained from the Materials Project database (MP-ID: mp-3249311, 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_Pa2AlSi2
_symmetry_space_group_name_H-M 'P 1'
_cell_length_a 5.61507997
_cell_length_b 5.61507975
_cell_length_c 5.61508033
_cell_angle_alpha 138.94433970
_cell_angle_beta 119.36150693
_cell_angle_gamma 75.85419266
_symmetry_Int_Tables_number 1
_chemical_formula_structural Pa2AlSi2
_chemical_formula_sum 'Pa2 Al1 Si2'
_cell_volume 98.88143291
_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
Pa Pa0 1 0.71812237 0.21812237 0.50000000 1.0
Pa Pa1 1 0.28187763 0.78187763 0.50000000 1.0
Al Al2 1 0.00000000 0.00000000 0.00000000 1.0
Si Si3 1 0.29197595 0.50000000 0.79197595 1.0
Si Si4 1 0.70802405 0.50000000 0.20802405 1.0
