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Pa2Al9MoIr2

High-Entropy Materials HEA

MP-ID: mp-3297416 · Space group: Cmcm (#63)

Basic Information

Formula
Pa2Al9MoIr2
MP-ID
mp-3297416
Elements
4
Sites
28
Density
8.3306
g/cm³
Volume
472.52
ų
Cell a
7.5513
Å
Cell b
7.5513
Å
Cell c
9.2973
Å
α Angle
90.00
°
β Angle
90.00
°
γ Angle
116.96
°
Space Group
Cmcm
Point Group
mmm
Crystal System
Orthorhombic
Bravais Lattice
Orthorhombic C
Stability
Yes
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
13.15 6.7305 1.4 (0,1,-1,0)
13.15 6.7305 1.4 (1,0,-1,0)
13.76 6.4372 15.0 (1,-1,0,0)
16.26 5.4519 17.0 (0,1,-1,1)
16.26 5.4519 17.0 (1,0,-1,1)
22.52 3.9476 10.5 (1,1,-2,0)
23.26 3.8250 25.0 (1,0,-1,2)
23.60 3.7705 4.6 (1,-2,1,0)
23.60 3.7705 4.6 (2,-1,-1,0)
24.50 3.6337 31.1 (1,1,-2,1)
25.49 3.4941 32.8 (2,-1,-1,1)
27.72 3.2186 14.8 (2,-2,0,0)
28.20 3.1643 1.9 (0,2,-2,1)
28.20 3.1643 1.9 (2,0,-2,1)
29.69 3.0091 36.3 (1,1,-2,2)
30.53 2.9283 100.0 (2,-1,-1,2)
31.79 2.8150 10.0 (1,0,-1,3)
32.86 2.7259 5.2 (2,0,-2,2)
33.87 2.6462 17.7 (2,-2,0,2)
34.79 2.5784 13.7 (2,1,-3,0)
36.87 2.4377 22.6 (1,1,-2,3)
37.32 2.4093 13.4 (1,-3,2,1)
37.32 2.4093 13.4 (3,-1,-2,1)
37.57 2.3942 33.1 (2,-1,-1,3)
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Energy Properties

Formation Energy/atom
-0.66123
eV/atom
Energy/atom
-25.31063
eV/atom
Energy above Hull
0.0000
eV/atom
Uncorrected Energy
-25.3106
eV/atom
Volume/atom
16.88
ų
c/a Ratio
-

Electronic Properties

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

Magnetic Properties

Magnetic
No
Total Mag. Moment
0.0050
μB
Mag. Ordering
NM
Mag. Sites
0
Magnetization/Volume
0.000010
μB/ų

Elastic Properties

Elastic data not available

Feature Analysis

Composition Overview

Element Composition (atomic fraction)
Composition Info
Major / Matrix Element
Al · 0.643
Element Family
PostTransition-Noble
Solute Fraction
0.357
Interstitial Fraction
0.000

High-Entropy Alloy Features

Composite Radar (normalized)
Element-Class Share
Mix Entropy ΔS/R
1.0285
HEA criterion (>1.0 = high entropy)
Mix Entropy ΔS
8.5511
J/mol·K
Ω Parameter
1.7431
Ω > 1.1 favors solid solution
Atomic Size Mismatch δr
9.320%
δr < 6.6% favors single-phase solid solution
Electronegativity Diff Δχ
0.2479
smaller = more stable mixing
VEC
4.250
valence electron concentration, affects phase stability
Mix Enthalpy ΔH_mix
-7.168
kJ/mol; negative = exothermic mixing
Entropy Norm
0.7419
SS Former
0
Phase Tendency
IM

Related Tasks

Related computation task IDs (1)

Citation & References

Materials Project Page
https://materialsproject.org/materials/mp-3297416
Reference Citation

The crystal structure and related material properties of Pa2Al9MoIr2 were obtained from the Materials Project database (MP-ID: mp-3297416, 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_Pa2Al9MoIr2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.55127185
_cell_length_b   7.55127369
_cell_length_c   9.29730611
_cell_angle_alpha   90.00000000
_cell_angle_beta   90.00000000
_cell_angle_gamma   116.96245023
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Pa2Al9MoIr2
_chemical_formula_sum   'Pa4 Al18 Mo2 Ir4'
_cell_volume   472.52330854
_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
  Pa  Pa0  1  0.99481992  0.70613921  0.25000000  1.0
  Pa  Pa1  1  0.00518008  0.29386079  0.75000000  1.0
  Pa  Pa2  1  0.70613921  0.99481992  0.25000000  1.0
  Pa  Pa3  1  0.29386079  0.00518008  0.75000000  1.0
  Al  Al4  1  0.15689530  0.15689530  0.25000000  1.0
  Al  Al5  1  0.84310470  0.84310470  0.75000000  1.0
  Al  Al6  1  0.01043280  0.35450487  0.08370014  1.0
  Al  Al7  1  0.98956720  0.64549513  0.91629986  1.0
  Al  Al8  1  0.98956720  0.64549513  0.58370014  1.0
  Al  Al9  1  0.35450487  0.01043280  0.41629986  1.0
  Al  Al10  1  0.01043280  0.35450487  0.41629986  1.0
  Al  Al11  1  0.64549513  0.98956720  0.58370014  1.0
  Al  Al12  1  0.64549513  0.98956720  0.91629986  1.0
  Al  Al13  1  0.35450487  0.01043280  0.08370014  1.0
  Al  Al14  1  0.33666988  0.33666988  0.53513151  1.0
  Al  Al15  1  0.66333012  0.66333012  0.46486849  1.0
  Al  Al16  1  0.66333012  0.66333012  0.03513151  1.0
  Al  Al17  1  0.33666988  0.33666988  0.96486849  1.0
  Al  Al18  1  0.35251203  0.56768742  0.25000000  1.0
  Al  Al19  1  0.64748797  0.43231258  0.75000000  1.0
  Al  Al20  1  0.56768742  0.35251203  0.25000000  1.0
  Al  Al21  1  0.43231258  0.64748797  0.75000000  1.0
  Mo  Mo22  1  0.00000000  0.00000000  0.00000000  1.0
  Mo  Mo23  1  0.00000000  0.00000000  0.50000000  1.0
  Ir  Ir24  1  0.67466710  0.32533290  0.00000000  1.0
  Ir  Ir25  1  0.32533290  0.67466710  0.00000000  1.0
  Ir  Ir26  1  0.32533290  0.67466710  0.50000000  1.0
  Ir  Ir27  1  0.67466710  0.32533290  0.50000000  1.0
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