Ho2Al4CoNi

High-Entropy Materials HEA

MP-ID: mp-3249404 · Space group: Amm2 (#38)

Materials Project API

Basic Information

Formula

Ho2Al4CoNi

MP-ID

mp-3249404

Elements

Sites

Density

6.6448

g/cm³

Volume

138.80

Å³

Cell a

5.3994

Cell b

5.3994

Cell c

6.9023

α Angle

90.00

β Angle

90.00

γ Angle

136.39

Space Group

Amm2

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
17.69	5.0131	4.9	(1,-1,0)
21.91	4.0562	20.2	(1,-1,1)
23.89	3.7243	72.5	(1,0,0)
25.82	3.4512	55.2	(0,0,2)
31.47	2.8427	12.5	(1,-1,2)
34.94	2.5677	10.9	(2,-1,0)
35.46	2.5314	100.0	(1,0,2)
37.37	2.4065	96.7	(2,-1,1)
38.20	2.3560	59.2	(2,-2,1)
43.27	2.0911	12.7	(1,-1,3)
44.68	2.0281	4.6	(2,-2,2)
45.21	2.0056	28.0	(1,1,0)
46.39	1.9574	2.2	(1,0,3)
50.78	1.7979	4.7	(2,0,1)
52.73	1.7360	11.5	(3,-2,1)
52.79	1.7341	15.5	(1,1,2)
53.07	1.7256	12.3	(0,0,4)
53.48	1.7135	31.8	(2,-1,3)
54.11	1.6950	12.9	(2,-2,3)
56.12	1.6388	2.6	(0,2,2)
56.12	1.6388	2.6	(2,0,2)
56.39	1.6316	1.4	(1,-1,4)
56.68	1.6241	2.0	(3,-3,1)
59.00	1.5657	16.9	(1,0,4)

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Energy Properties

Formation Energy/atom

-0.60367

eV/atom

Energy/atom

-15.34205

eV/atom

Energy above Hull

0.0000

eV/atom

Uncorrected Energy

-15.3421

eV/atom

Volume/atom

17.35

Å³

c/a Ratio

1.2783

Electronic Properties

Metallic

Metal

Band Gap

Direct Gap

CBM

N/A

Magnetic Properties

Magnetic

Total Mag. Moment

0.0000

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

Al · 0.500

Element Family

PostTransition-Noble

Solute Fraction

0.500

Interstitial Fraction

0.000

High-Entropy Alloy Features

Composite Radar (normalized)

Element-Class Share

Mix Entropy ΔS/R

1.2130

HEA criterion (>1.0 = high entropy)

Mix Entropy ΔS

10.0849

J/mol·K

Ω Parameter

1.3157

Ω > 1.1 favors solid solution

Atomic Size Mismatch δr

12.415%

δr < 6.6% favors single-phase solid solution

Electronegativity Diff Δχ

0.2364

smaller = more stable mixing

VEC

6.625

valence electron concentration, affects phase stability

Mix Enthalpy ΔH_mix

-10.250

kJ/mol; negative = exothermic mixing

Entropy Norm

0.8750

SS Former

Phase Tendency

Related Tasks

Related computation task IDs (1)

aaahcwvc

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-3249404

Reference Citation

The crystal structure and related material properties of Ho2Al4CoNi were obtained from the Materials Project database (MP-ID: mp-3249404, 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_Ho2Al4CoNi
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.39942876
_cell_length_b   5.39942893
_cell_length_c   6.90230146
_cell_angle_alpha   90.00000000
_cell_angle_beta   90.00000000
_cell_angle_gamma   136.38944043
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ho2Al4CoNi
_chemical_formula_sum   'Ho2 Al4 Co1 Ni1'
_cell_volume   138.79798589
_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
  Ho  Ho0  1  0.05865844  0.94134156  0.25000000  1.0
  Ho  Ho1  1  0.94024727  0.05975273  0.75000000  1.0
  Al  Al2  1  0.66092811  0.33907189  0.94527854  1.0
  Al  Al3  1  0.33860758  0.66139242  0.05638039  1.0
  Al  Al4  1  0.33860758  0.66139242  0.44361961  1.0
  Al  Al5  1  0.66092811  0.33907189  0.55472146  1.0
  Co  Co6  1  0.78640724  0.21359276  0.25000000  1.0
  Ni  Ni7  1  0.21561467  0.78438533  0.75000000  1.0

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