Ta18Nb2Al9Pd

High-Entropy Materials HEA

MP-ID: mp-3292715 · Space group: Cmm2 (#35)

Materials Project API

Basic Information

Formula

Ta18Nb2Al9Pd

MP-ID

mp-3292715

Elements

Sites

Density

12.3814

g/cm³

Volume

508.59

Å³

Cell a

9.9055

Cell b

9.9055

Cell c

5.1835

α Angle

90.00

β Angle

90.00

γ Angle

90.35

Space Group

Cmm2

Point Group

mm2

Crystal System

Orthorhombic

Bravais Lattice

Stability

Yes

Packing Fraction

X-ray Diffraction

Diffraction Pattern

Target / Radiation

X-axis: 2θ (°); Y-axis: relative intensity; Cu Kα ; λ=1.5418 Å

Diffraction Peaks (Top 24)

2θ	d (Å)	I	hkl
8.93	9.9053	12.0	(1,0,0)
12.60	7.0254	11.1	(1,-1,0)
17.11	5.1835	2.3	(0,0,1)
19.33	4.5926	59.0	(1,0,1)
20.00	4.4406	7.0	(2,-1,0)
20.09	4.4191	10.7	(2,1,0)
21.30	4.1711	8.9	(1,-1,1)
21.35	4.1621	17.1	(1,1,1)
24.86	3.5809	1.9	(2,0,1)
25.36	3.5127	5.5	(2,-2,0)
25.51	3.4915	8.9	(2,2,0)
26.43	3.3723	12.1	(2,-1,1)
26.51	3.3629	13.4	(2,1,1)
28.44	3.1380	4.9	(3,-1,0)
28.55	3.1267	7.0	(3,1,0)
32.14	2.7848	25.6	(3,0,1)
32.50	2.7550	16.5	(3,-2,0)
32.69	2.7396	4.4	(3,2,0)
33.38	2.6844	25.1	(3,-1,1)
33.47	2.6773	34.9	(3,1,1)
34.61	2.5917	17.5	(0,0,2)
36.28	2.4763	12.2	(4,0,0)
36.95	2.4327	3.3	(3,-2,1)
36.97	2.4316	4.0	(1,-1,2)

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Energy Properties

Formation Energy/atom

-0.31837

eV/atom

Energy/atom

-33.90739

eV/atom

Energy above Hull

0.0000

eV/atom

Uncorrected Energy

-33.9074

eV/atom

Volume/atom

16.95

Å³

c/a Ratio

0.5233

Electronic Properties

Metallic

Metal

Band Gap

Direct Gap

CBM

N/A

Magnetic Properties

Magnetic

Total Mag. Moment

0.0017

μB

Mag. Ordering

Mag. Sites

Magnetization/Volume

0.000000

μB/Å³

Elastic Properties

Elastic data not available

Feature Analysis

Composition Overview

Element Composition (atomic fraction)

Composition Info

Major / Matrix Element

Ta · 0.600

Element Family

5d-TM

Solute Fraction

0.400

Interstitial Fraction

0.000

High-Entropy Alloy Features

Composite Radar (normalized)

Element-Class Share

Mix Entropy ΔS/R

0.9616

HEA criterion (>1.0 = high entropy)

Mix Entropy ΔS

7.9947

J/mol·K

Ω Parameter

0.9496

Ω > 1.1 favors solid solution

Atomic Size Mismatch δr

1.374%

δr < 6.6% favors single-phase solid solution

Electronegativity Diff Δχ

0.1291

smaller = more stable mixing

VEC

4.567

valence electron concentration, affects phase stability

Mix Enthalpy ΔH_mix

-21.033

kJ/mol; negative = exothermic mixing

Entropy Norm

0.6936

SS Former

Phase Tendency

Related Tasks

Related computation task IDs (1)

aaahfiwx

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-3292715

Reference Citation

The crystal structure and related material properties of Ta18Nb2Al9Pd were obtained from the Materials Project database (MP-ID: mp-3292715, 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_Ta18Nb2Al9Pd
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.90547508
_cell_length_b   9.90547505
_cell_length_c   5.18347743
_cell_angle_alpha   90.00000000
_cell_angle_beta   90.00000000
_cell_angle_gamma   90.34722173
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ta18Nb2Al9Pd
_chemical_formula_sum   'Ta18 Nb2 Al9 Pd1'
_cell_volume   508.58536080
_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
  Ta  Ta0  1  0.39849299  0.39849299  0.00043705  1.0
  Ta  Ta1  1  0.89765362  0.10234638  0.49864054  1.0
  Ta  Ta2  1  0.10234638  0.89765362  0.49864054  1.0
  Ta  Ta3  1  0.60150701  0.60150701  0.00043705  1.0
  Ta  Ta4  1  0.13034698  0.46604612  0.00060271  1.0
  Ta  Ta5  1  0.96374002  0.37146620  0.49972746  1.0
  Ta  Ta6  1  0.03625998  0.62853380  0.49972746  1.0
  Ta  Ta7  1  0.86965302  0.53395388  0.00060271  1.0
  Ta  Ta8  1  0.37146620  0.96374002  0.49972746  1.0
  Ta  Ta9  1  0.62853380  0.03625998  0.49972746  1.0
  Ta  Ta10  1  0.46604612  0.13034698  0.00060271  1.0
  Ta  Ta11  1  0.53395388  0.86965302  0.00060271  1.0
  Ta  Ta12  1  0.18265404  0.18265404  0.25188728  1.0
  Ta  Ta13  1  0.68266510  0.31733490  0.75163838  1.0
  Ta  Ta14  1  0.31733490  0.68266510  0.75163838  1.0
  Ta  Ta15  1  0.81734596  0.81734596  0.25188728  1.0
  Ta  Ta16  1  0.31694315  0.68305685  0.24885399  1.0
  Ta  Ta17  1  0.68305685  0.31694315  0.24885399  1.0
  Nb  Nb18  1  0.18182177  0.18182177  0.74698272  1.0
  Nb  Nb19  1  0.81817823  0.81817823  0.74698272  1.0
  Al  Al20  1  0.00000000  0.00000000  0.00012717  1.0
  Al  Al21  1  0.26186639  0.93438198  0.00002475  1.0
  Al  Al22  1  0.43497948  0.24266910  0.50035578  1.0
  Al  Al23  1  0.56502052  0.75733090  0.50035578  1.0
  Al  Al24  1  0.73813361  0.06561802  0.00002475  1.0
  Al  Al25  1  0.24266910  0.43497948  0.50035578  1.0
  Al  Al26  1  0.75733090  0.56502052  0.50035578  1.0
  Al  Al27  1  0.93438198  0.26186639  0.00002475  1.0
  Al  Al28  1  0.06561802  0.73813361  0.00002475  1.0
  Pd  Pd29  1  0.50000000  0.50000000  0.50015608  1.0

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