Ho2NiAs2

High-Entropy Materials HEA Traditional Materials TRA

MP-ID: mp-8787 · Space group: P6_3/mmc (#194)

Materials Project API

Basic Information

Formula

Ho2NiAs2

MP-ID

mp-8787

Elements

Sites

Density

8.8404

g/cm³

Volume

202.26

Å³

Cell a

4.0649

Cell b

4.0649

Cell c

14.1348

α Angle

90.00

β Angle

90.00

γ Angle

120.00

Space Group

P6_3/mmc

Point Group

6/mmm

Crystal System

Hexagonal

Bravais Lattice

Stability

Packing Fraction

0.7405

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
12.52	7.0674	2.4	(0,0,0,2)
25.20	3.5337	3.3	(0,0,0,4)
25.30	3.5203	3.4	(1,0,-1,0)
26.09	3.4159	28.8	(1,0,-1,1)
28.32	3.1510	2.0	(1,0,-1,2)
31.73	2.8201	100.0	(1,0,-1,3)
36.01	2.4939	19.4	(1,0,-1,4)
36.01	2.4939	38.8	(1,-1,0,4)
38.20	2.3558	2.8	(0,0,0,6)
40.94	2.2042	27.1	(1,0,-1,5)
44.58	2.0324	45.4	(2,-1,-1,0)
44.58	2.0324	22.7	(1,-2,1,0)
46.38	1.9578	3.8	(1,0,-1,6)
51.74	1.7669	13.4	(0,0,0,8)
51.90	1.7618	2.1	(2,-1,-1,4)
51.90	1.7618	1.1	(1,-2,1,4)
52.22	1.7516	10.1	(1,0,-1,7)
52.38	1.7467	1.5	(2,0,-2,1)
52.38	1.7467	2.9	(2,-2,0,1)
55.75	1.6488	20.3	(2,0,-2,3)
58.59	1.5755	9.3	(2,0,-2,4)
58.59	1.5755	4.6	(2,-2,0,4)
60.13	1.5389	4.4	(2,-1,-1,6)
62.12	1.4942	7.9	(2,0,-2,5)

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Energy Properties

Formation Energy/atom

-1.22456

eV/atom

Energy/atom

-6.08770

eV/atom

Energy above Hull

0.0017

eV/atom

Uncorrected Energy

-22.8394

eV/atom

Volume/atom

20.23

Å³

c/a Ratio

3.4773

Electronic Properties

Metallic

Metal

Band Gap

Direct Gap

CBM

N/A

Magnetic Properties

Magnetic

Yes

Total Mag. Moment

0.0000

μB

Mag. Ordering

Unknown

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

Ho · 0.400

Element Family

Lanthanide

Solute Fraction

0.600

Interstitial Fraction

0.000

High-Entropy Alloy Features

Composite Radar (normalized)

Element-Class Share

Mix Entropy ΔS/R

1.0549

HEA criterion (>1.0 = high entropy)

Mix Entropy ΔS

8.7706

J/mol·K

Ω Parameter

0.0000

Ω > 1.1 favors solid solution

Atomic Size Mismatch δr

19.969%

δr < 6.6% favors single-phase solid solution

Electronegativity Diff Δχ

0.4327

smaller = more stable mixing

VEC

7.600

valence electron concentration, affects phase stability

Mix Enthalpy ΔH_mix

0.000

kJ/mol; negative = exothermic mixing

Entropy Norm

0.9602

SS Former

Phase Tendency

Traditional Material Features

ROM Blended-Feature Radar

Rating & Classification

Tier

Score

0.413

Family

Ho-rich Multi-Component

Matrix Element

Ho · 0.400

Related Tasks

Related computation task IDs (5)

aaadndsp aaadsumr aaaektjz aaaeucca aaafsdpk

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-8787

Reference Citation

The crystal structure and related material properties of Ho2NiAs2 were obtained from the Materials Project database (MP-ID: mp-8787, 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_Ho2NiAs2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.06486699
_cell_length_b   4.06486671
_cell_length_c   14.13477441
_cell_angle_alpha   90.00000000
_cell_angle_beta   90.00000000
_cell_angle_gamma   119.99999409
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ho2NiAs2
_chemical_formula_sum   'Ho4 Ni2 As4'
_cell_volume   202.26101730
_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  0.66666700  0.33333300  0.38239464  1.0
  Ho  Ho1  1  0.33333300  0.66666700  0.88239464  1.0
  Ho  Ho2  1  0.33333300  0.66666700  0.61760536  1.0
  Ho  Ho3  1  0.66666700  0.33333300  0.11760536  1.0
  Ni  Ni4  1  -0.00000000  0.00000000  0.75000000  1.0
  Ni  Ni5  1  0.00000000  -0.00000000  0.25000000  1.0
  As  As6  1  0.33333300  0.66666700  0.25000000  1.0
  As  As7  1  -0.00000000  -0.00000000  -0.00000000  1.0
  As  As8  1  -0.00000000  -0.00000000  0.50000000  1.0
  As  As9  1  0.66666700  0.33333300  0.75000000  1.0

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