Ho2Al9OsPt2

High-Entropy Materials HEA

MP-ID: mp-3296314 · Space group: Cmcm (#63)

Materials Project API

Basic Information

Formula

Ho2Al9OsPt2

MP-ID

mp-3296314

Elements

Sites

Density

8.2400

g/cm³

Volume

464.75

Å³

Cell a

7.5319

Cell b

7.5319

Cell c

9.3974

α Angle

90.00

β Angle

90.00

γ Angle

119.33

Space Group

Cmcm

Point Group

mmm

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
13.49	6.5661	3.6	(1,0,-1,0)
13.49	6.5661	3.6	(0,1,-1,0)
13.62	6.5009	9.9	(1,-1,0,0)
16.47	5.3824	20.8	(1,0,-1,1)
18.89	4.6987	24.0	(0,0,0,2)
23.28	3.8211	3.2	(1,0,-1,2)
23.36	3.8081	2.7	(1,-1,0,2)
23.39	3.8038	26.2	(1,1,-2,0)
23.63	3.7657	50.7	(2,-1,-1,0)
25.26	3.5259	17.8	(1,1,-2,1)
25.48	3.4955	17.9	(2,-1,-1,1)
25.48	3.4955	17.9	(1,-2,1,1)
27.44	3.2504	4.7	(2,-2,0,0)
28.81	3.0994	8.5	(2,0,-2,1)
30.23	2.9564	85.7	(1,1,-2,2)
30.42	2.9385	85.1	(2,-1,-1,2)
30.42	2.9385	85.1	(1,-2,1,2)
31.65	2.8272	5.7	(1,0,-1,3)
33.29	2.6912	4.5	(2,0,-2,2)
33.52	2.6731	12.3	(2,-2,0,2)
36.09	2.4889	5.9	(2,1,-3,0)
36.36	2.4711	1.5	(3,-1,-2,0)
37.18	2.4181	21.7	(1,1,-2,3)
37.34	2.4082	43.7	(2,-1,-1,3)

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Energy Properties

Formation Energy/atom

-0.90316

eV/atom

Energy/atom

-21.06831

eV/atom

Energy above Hull

0.0000

eV/atom

Uncorrected Energy

-21.0683

eV/atom

Volume/atom

16.60

Å³

c/a Ratio

1.2477

Electronic Properties

Metallic

Metal

Band Gap

Direct Gap

CBM

N/A

Magnetic Properties

Magnetic

Total Mag. Moment

0.0005

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 · 0.643

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

0.6285

Ω > 1.1 favors solid solution

Atomic Size Mismatch δr

8.120%

δr < 6.6% favors single-phase solid solution

Electronegativity Diff Δχ

0.3204

smaller = more stable mixing

VEC

5.500

valence electron concentration, affects phase stability

Mix Enthalpy ΔH_mix

-18.716

kJ/mol; negative = exothermic mixing

Entropy Norm

0.7419

SS Former

Phase Tendency

Related Tasks

Related computation task IDs (1)

aaahfofi

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-3296314

Reference Citation

The crystal structure and related material properties of Ho2Al9OsPt2 were obtained from the Materials Project database (MP-ID: mp-3296314, 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_Ho2Al9OsPt2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.53189740
_cell_length_b   7.53189677
_cell_length_c   9.39739421
_cell_angle_alpha   90.00000000
_cell_angle_beta   90.00000000
_cell_angle_gamma   119.33487108
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ho2Al9OsPt2
_chemical_formula_sum   'Ho4 Al18 Os2 Pt4'
_cell_volume   464.74930588
_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
  Ho  Ho0  1  0.99368034  0.67284036  0.25000000  1.0
  Ho  Ho1  1  0.00631966  0.32715964  0.75000000  1.0
  Ho  Ho2  1  0.67284036  0.99368034  0.25000000  1.0
  Ho  Ho3  1  0.32715964  0.00631966  0.75000000  1.0
  Al  Al4  1  0.12699504  0.12699504  0.25000000  1.0
  Al  Al5  1  0.87300496  0.87300496  0.75000000  1.0
  Al  Al6  1  0.00074172  0.33107302  0.07526997  1.0
  Al  Al7  1  0.99925828  0.66892698  0.92473003  1.0
  Al  Al8  1  0.99925828  0.66892698  0.57526997  1.0
  Al  Al9  1  0.33107302  0.00074172  0.42473003  1.0
  Al  Al10  1  0.00074172  0.33107302  0.42473003  1.0
  Al  Al11  1  0.66892698  0.99925828  0.57526997  1.0
  Al  Al12  1  0.66892698  0.99925828  0.92473003  1.0
  Al  Al13  1  0.33107302  0.00074172  0.07526997  1.0
  Al  Al14  1  0.32899133  0.32899133  0.55228456  1.0
  Al  Al15  1  0.67100867  0.67100967  0.44771544  1.0
  Al  Al16  1  0.67100867  0.67100967  0.05228456  1.0
  Al  Al17  1  0.32899133  0.32899133  0.94771544  1.0
  Al  Al18  1  0.34144642  0.54658724  0.25000000  1.0
  Al  Al19  1  0.65855358  0.45341276  0.75000000  1.0
  Al  Al20  1  0.54658724  0.34144642  0.25000000  1.0
  Al  Al21  1  0.45341276  0.65855358  0.75000000  1.0
  Os  Os22  1  0.00000000  0.00000000  0.00000000  1.0
  Os  Os23  1  0.00000000  0.00000000  0.50000000  1.0
  Pt  Pt24  1  0.67213821  0.32786179  0.00000000  1.0
  Pt  Pt25  1  0.32786179  0.67213821  0.00000000  1.0
  Pt  Pt26  1  0.32786179  0.67213821  0.50000000  1.0
  Pt  Pt27  1  0.67213821  0.32786179  0.50000000  1.0

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