Er9Al(SiB4)4

High-Entropy Materials HEA

MP-ID: mp-3295265 · Space group: P4/m (#83)

Materials Project API

Basic Information

Formula

Er9Al(SiB4)4

MP-ID

mp-3295265

Elements

Sites

Density

7.6119

g/cm³

Volume

396.52

Å³

Cell a

7.1078

Cell b

7.1078

Cell c

7.8486

α Angle

90.00

β Angle

90.00

γ Angle

90.00

Space Group

P4/m

Point Group

4/m

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
12.45	7.1078	5.2	(1,0,0)
16.83	5.2685	6.2	(1,0,1)
20.99	4.2325	3.5	(1,1,1)
22.66	3.9243	31.6	(0,0,2)
25.06	3.5539	22.6	(2,0,0)
25.94	3.4355	2.5	(1,0,2)
27.55	3.2375	7.9	(2,0,1)
28.07	3.1787	68.7	(2,1,0)
28.86	3.0931	11.1	(1,1,2)
30.34	2.9462	8.4	(2,1,1)
34.03	2.6342	64.9	(2,0,2)
34.28	2.6162	8.7	(0,0,3)
35.73	2.5130	14.9	(2,2,0)
36.37	2.4701	100.0	(2,1,2)
40.12	2.2477	24.6	(3,1,0)
41.80	2.1608	2.0	(3,1,1)
42.73	2.1163	4.6	(2,2,2)
44.87	2.0200	6.6	(2,1,3)
46.04	1.9714	3.8	(3,2,0)
46.27	1.9621	14.7	(0,0,4)
46.56	1.9504	4.8	(3,1,2)
47.56	1.9120	1.0	(3,2,1)
50.35	1.8123	4.3	(2,2,3)
51.91	1.7616	1.8	(3,2,2)

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Energy Properties

Formation Energy/atom

-0.72621

eV/atom

Energy/atom

-16.21614

eV/atom

Energy above Hull

0.0000

eV/atom

Uncorrected Energy

-16.2161

eV/atom

Volume/atom

13.22

Å³

c/a Ratio

1.1042

Electronic Properties

Metallic

Metal

Band Gap

Direct Gap

CBM

N/A

Magnetic Properties

Magnetic

Total Mag. Moment

0.0008

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

B · 0.533

Element Family

Metalloid-Nonmetal

Solute Fraction

0.467

Interstitial Fraction

0.667

High-Entropy Alloy Features

Composite Radar (normalized)

Element-Class Share

Mix Entropy ΔS/R

1.0785

HEA criterion (>1.0 = high entropy)

Mix Entropy ΔS

8.9665

J/mol·K

Ω Parameter

4.5659

Ω > 1.1 favors solid solution

Atomic Size Mismatch δr

31.019%

δr < 6.6% favors single-phase solid solution

Electronegativity Diff Δχ

0.3553

smaller = more stable mixing

VEC

5.833

valence electron concentration, affects phase stability

Mix Enthalpy ΔH_mix

-4.025

kJ/mol; negative = exothermic mixing

Entropy Norm

0.7780

SS Former

Phase Tendency

Related Tasks

Related computation task IDs (1)

aaahfmqz

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-3295265

Reference Citation

The crystal structure and related material properties of Er9Al(SiB4)4 were obtained from the Materials Project database (MP-ID: mp-3295265, 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_Er9Al(SiB4)4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.10779567
_cell_length_b   7.10779567
_cell_length_c   7.84857848
_cell_angle_alpha   90.00000000
_cell_angle_beta   90.00000000
_cell_angle_gamma   90.00000000
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Er9Al(SiB4)4
_chemical_formula_sum   'Er9 Al1 Si4 B16'
_cell_volume   396.51614438
_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
  Er  Er0  1  0.68172600  0.17964944  0.22849870  1.0
  Er  Er1  1  0.31827400  0.82035056  0.77150130  1.0
  Er  Er2  1  0.31827400  0.82035056  0.22849870  1.0
  Er  Er3  1  0.82035056  0.68172600  0.22849870  1.0
  Er  Er4  1  0.82035056  0.68172600  0.77150130  1.0
  Er  Er5  1  0.68172600  0.17964944  0.77150130  1.0
  Er  Er6  1  0.17964944  0.31827400  0.77150130  1.0
  Er  Er7  1  0.17964944  0.31827400  0.22849870  1.0
  Er  Er8  1  0.50000000  0.50000000  0.50000000  1.0
  Al  Al9  1  0.00000000  0.00000000  0.50000000  1.0
  Si  Si10  1  0.11395447  0.62098260  0.50000000  1.0
  Si  Si11  1  0.88604553  0.37901740  0.50000000  1.0
  Si  Si12  1  0.37901740  0.11395447  0.50000000  1.0
  Si  Si13  1  0.62098260  0.88604553  0.50000000  1.0
  B  B14  1  0.17430582  0.03894445  0.00000000  1.0
  B  B15  1  0.82569418  0.96105555  0.00000000  1.0
  B  B16  1  0.96105555  0.17430582  0.00000000  1.0
  B  B17  1  0.32717648  0.53943631  0.00000000  1.0
  B  B18  1  0.03894445  0.82569418  0.00000000  1.0
  B  B19  1  0.67282352  0.46056369  0.00000000  1.0
  B  B20  1  0.53943631  0.67282352  0.00000000  1.0
  B  B21  1  0.46056369  0.32717648  0.00000000  1.0
  B  B22  1  0.08969483  0.58881427  0.00000000  1.0
  B  B23  1  0.91030517  0.41118573  0.00000000  1.0
  B  B24  1  0.41118573  0.08969483  0.00000000  1.0
  B  B25  1  0.58881427  0.91030517  0.00000000  1.0
  B  B26  1  0.00000000  0.00000000  0.16335199  1.0
  B  B27  1  0.00000000  0.00000000  0.83664801  1.0
  B  B28  1  0.50000000  0.50000000  0.83376357  1.0
  B  B29  1  0.50000000  0.50000000  0.16623643  1.0

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