TbAl9(Fe2Si3)2

High-Entropy Materials HEA

MP-ID: mp-6563 · Space group: P4_2/nmc (#137)

Materials Project API

Basic Information

Formula

TbAl9(Fe2Si3)2

MP-ID

mp-6563

Elements

Sites

Density

4.6073

g/cm³

Volume

1,144.17

Å³

Cell a

8.6654

Cell b

8.6654

Cell c

15.2374

α Angle

90.00

β Angle

90.00

γ Angle

90.00

Space Group

P4_2/nmc

Point Group

4/mmm

Crystal System

Tetragonal

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
11.62	7.6187	10.6	(0,0,2)
11.75	7.5325	1.8	(1,0,1)
14.46	6.1274	79.1	(1,1,0)
15.49	5.7217	53.0	(1,0,2)
18.58	4.7748	1.9	(1,1,2)
20.50	4.3327	2.1	(2,0,0)
21.32	4.1675	21.5	(2,0,1)
23.35	3.8093	6.2	(0,0,4)
23.62	3.7663	1.2	(2,0,2)
25.54	3.4873	22.6	(1,0,4)
25.79	3.4541	39.5	(2,1,2)
27.05	3.2963	15.0	(2,0,3)
27.57	3.2351	4.5	(1,1,4)
29.15	3.0637	12.4	(2,2,0)
31.11	2.8749	3.2	(1,0,5)
31.27	2.8609	20.5	(2,0,4)
31.47	2.8425	28.9	(2,2,2)
32.68	2.7403	12.8	(3,1,0)
32.97	2.7166	41.7	(2,1,4)
33.17	2.7009	30.0	(3,0,2)
34.79	2.5785	27.7	(3,1,2)
35.34	2.5396	13.1	(0,0,6)
36.88	2.4371	3.3	(1,0,6)
37.55	2.3955	2.5	(2,1,5)

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Energy Properties

Formation Energy/atom

-0.37441

eV/atom

Energy/atom

-5.61341

eV/atom

Energy above Hull

0.0000

eV/atom

Uncorrected Energy

-5.6347

eV/atom

Volume/atom

14.30

Å³

c/a Ratio

1.7584

Electronic Properties

Metallic

Metal

Band Gap

Direct Gap

CBM

N/A

Magnetic Properties

Magnetic

Total Mag. Moment

0.0265

μB

Mag. Ordering

Mag. Sites

Magnetization/Volume

0.000020

μB/Å³

Elastic Properties

Elastic data not available

Feature Analysis

Composition Overview

Element Composition (atomic fraction)

Composition Info

Major / Matrix Element

Al · 0.450

Element Family

PostTransition-Noble

Solute Fraction

0.550

Interstitial Fraction

0.300

High-Entropy Alloy Features

Composite Radar (normalized)

Element-Class Share

Mix Entropy ΔS/R

1.1922

HEA criterion (>1.0 = high entropy)

Mix Entropy ΔS

9.9119

J/mol·K

Ω Parameter

0.8140

Ω > 1.1 favors solid solution

Atomic Size Mismatch δr

11.110%

δr < 6.6% favors single-phase solid solution

Electronegativity Diff Δχ

0.1918

smaller = more stable mixing

VEC

4.600

valence electron concentration, affects phase stability

Mix Enthalpy ΔH_mix

-16.680

kJ/mol; negative = exothermic mixing

Entropy Norm

0.8600

SS Former

Phase Tendency

Related Tasks

Related computation task IDs (2)

aaacajia aaacxnra

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-6563

Reference Citation

The crystal structure and related material properties of TbAl9(Fe2Si3)2 were obtained from the Materials Project database (MP-ID: mp-6563, 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

Loading 3D structure…

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Raw CIF Data

# generated using pymatgen
data_TbAl9(Fe2Si3)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.66541700
_cell_length_b   8.66541700
_cell_length_c   15.23736500
_cell_angle_alpha   90.00000000
_cell_angle_beta   90.00000000
_cell_angle_gamma   90.00000000
_symmetry_Int_Tables_number   1
_chemical_formula_structural   TbAl9(Fe2Si3)2
_chemical_formula_sum   'Tb4 Al36 Fe16 Si24'
_cell_volume   1144.16538448
_cell_formula_units_Z   4
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
  Tb  Tb0  1  0.00000000  0.50000000  0.08572900  1.0
  Tb  Tb1  1  0.00000000  0.50000000  0.58572900  1.0
  Tb  Tb2  1  0.50000000  0.00000000  0.41427100  1.0
  Tb  Tb3  1  0.50000000  0.00000000  0.91427100  1.0
  Al  Al4  1  0.31696800  0.00000000  0.08904000  1.0
  Al  Al5  1  0.50000000  0.50000000  0.27290000  1.0
  Al  Al6  1  0.00000000  0.00000000  0.77290000  1.0
  Al  Al7  1  0.00000000  0.00000000  0.22710000  1.0
  Al  Al8  1  0.50000000  0.50000000  0.72710000  1.0
  Al  Al9  1  0.50000000  0.65496900  0.89737100  1.0
  Al  Al10  1  0.50000000  0.34503100  0.89737100  1.0
  Al  Al11  1  0.65496900  0.50000000  0.10262900  1.0
  Al  Al12  1  0.15496900  0.00000000  0.39737100  1.0
  Al  Al13  1  0.84503100  0.00000000  0.39737100  1.0
  Al  Al14  1  0.00000000  0.15496900  0.60262900  1.0
  Al  Al15  1  0.00000000  0.84503100  0.60262900  1.0
  Al  Al16  1  0.34503100  0.50000000  0.10262900  1.0
  Al  Al17  1  0.70243600  0.25442400  0.33083100  1.0
  Al  Al18  1  0.29756400  0.74557600  0.33083100  1.0
  Al  Al19  1  0.25442400  0.70243600  0.66916900  1.0
  Al  Al20  1  0.75442400  0.79756400  0.83083100  1.0
  Al  Al21  1  0.24557600  0.20243600  0.83083100  1.0
  Al  Al22  1  0.79756400  0.75442400  0.16916900  1.0
  Al  Al23  1  0.20243600  0.24557600  0.16916900  1.0
  Al  Al24  1  0.74557600  0.29756400  0.66916900  1.0
  Al  Al25  1  0.50000000  0.81696800  0.58904000  1.0
  Al  Al26  1  0.50000000  0.18303200  0.58904000  1.0
  Al  Al27  1  0.81696800  0.50000000  0.41096000  1.0
  Al  Al28  1  0.18303200  0.50000000  0.41096000  1.0
  Al  Al29  1  0.68303200  0.00000000  0.08904000  1.0
  Al  Al30  1  0.00000000  0.31696800  0.91096000  1.0
  Al  Al31  1  0.00000000  0.68303200  0.91096000  1.0
  Al  Al32  1  0.75442400  0.20243600  0.83083100  1.0
  Al  Al33  1  0.79756400  0.24557600  0.16916900  1.0
  Al  Al34  1  0.70243600  0.74557600  0.33083100  1.0
  Al  Al35  1  0.25442400  0.29756400  0.66916900  1.0
  Al  Al36  1  0.74557600  0.70243600  0.66916900  1.0
  Al  Al37  1  0.24557600  0.79756400  0.83083100  1.0
  Al  Al38  1  0.20243600  0.75442400  0.16916900  1.0
  Al  Al39  1  0.29756400  0.25442400  0.33083100  1.0
  Fe  Fe40  1  0.25511000  0.74489000  0.50000000  1.0
  Fe  Fe41  1  0.75511000  0.75511000  0.00000000  1.0
  Fe  Fe42  1  0.24489000  0.24489000  0.00000000  1.0
  Fe  Fe43  1  0.74489000  0.25511000  0.50000000  1.0
  Fe  Fe44  1  0.24489000  0.75511000  0.00000000  1.0
  Fe  Fe45  1  0.74489000  0.74489000  0.50000000  1.0
  Fe  Fe46  1  0.25511000  0.25511000  0.50000000  1.0
  Fe  Fe47  1  0.75511000  0.24489000  0.00000000  1.0
  Fe  Fe48  1  0.77744000  0.50000000  0.25041400  1.0
  Fe  Fe49  1  0.22256000  0.50000000  0.25041400  1.0
  Fe  Fe50  1  0.50000000  0.22256000  0.74958600  1.0
  Fe  Fe51  1  0.00000000  0.72256000  0.75041400  1.0
  Fe  Fe52  1  0.00000000  0.27744000  0.75041400  1.0
  Fe  Fe53  1  0.72256000  0.00000000  0.24958600  1.0
  Fe  Fe54  1  0.27744000  0.00000000  0.24958600  1.0
  Fe  Fe55  1  0.50000000  0.77744000  0.74958600  1.0
  Si  Si56  1  0.34382700  0.50000000  0.55614600  1.0
  Si  Si57  1  0.65617300  0.50000000  0.55614600  1.0
  Si  Si58  1  0.15617300  0.00000000  0.94385400  1.0
  Si  Si59  1  0.00000000  0.84382700  0.05614600  1.0
  Si  Si60  1  0.00000000  0.15617300  0.05614600  1.0
  Si  Si61  1  0.50000000  0.23938900  0.06143000  1.0
  Si  Si62  1  0.26061100  0.00000000  0.56143000  1.0
  Si  Si63  1  0.73938900  0.00000000  0.56143000  1.0
  Si  Si64  1  0.00000000  0.26061100  0.43857000  1.0
  Si  Si65  1  0.00000000  0.73938900  0.43857000  1.0
  Si  Si66  1  0.50000000  0.76061100  0.06143000  1.0
  Si  Si67  1  0.23938900  0.50000000  0.93857000  1.0
  Si  Si68  1  0.76061100  0.50000000  0.93857000  1.0
  Si  Si69  1  0.63787100  0.00000000  0.72023400  1.0
  Si  Si70  1  0.50000000  0.13787100  0.22023400  1.0
  Si  Si71  1  0.50000000  0.86212900  0.22023400  1.0
  Si  Si72  1  0.13787100  0.50000000  0.77976600  1.0
  Si  Si73  1  0.86212900  0.50000000  0.77976600  1.0
  Si  Si74  1  0.36212900  0.00000000  0.72023400  1.0
  Si  Si75  1  0.00000000  0.63787100  0.27976600  1.0
  Si  Si76  1  0.84382700  0.00000000  0.94385400  1.0
  Si  Si77  1  0.50000000  0.34382700  0.44385400  1.0
  Si  Si78  1  0.50000000  0.65617300  0.44385400  1.0
  Si  Si79  1  0.00000000  0.36212900  0.27976600  1.0

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