HoNi2B2C

High-Entropy Materials HEA Elasticity Data ELA

MP-ID: mp-6646 · Space group: I4/mmm (#139)

Materials Project API

Basic Information

Formula

HoNi2B2C

MP-ID

mp-6646

Elements

Sites

Density

8.1108

g/cm³

Volume

64.69

Å³

Cell a

5.7603

Cell b

5.7603

Cell c

5.7603

α Angle

144.32

β Angle

144.32

γ Angle

51.36

Space Group

I4/mmm

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 21)

2θ	d (Å)	I	hkl
17.08	5.1915	3.3	(1,1,-1)
26.67	3.3420	63.8	(1,0,-1)
34.55	2.5957	35.3	(2,2,-2)
35.98	2.4960	2.6	(1,-1,0)
36.35	2.4713	40.6	(2,1,-2)
40.08	2.2495	100.0	(2,0,-1)
51.03	1.7898	13.7	(3,2,-3)
51.80	1.7649	25.9	(1,-1,1)
59.20	1.5607	15.4	(2,-1,-1)
63.77	1.4595	22.8	(3,1,-3)
64.93	1.4363	15.1	(3,0,-2)
65.65	1.4221	23.8	(4,2,-3)
68.63	1.3675	4.7	(4,3,-4)
72.88	1.2979	4.3	(4,4,-4)
75.68	1.2567	8.7	(4,1,-3)
76.30	1.2480	7.9	(2,-2,0)
82.51	1.1691	3.0	(2,-1,-2)
86.54	1.1248	9.7	(4,0,-2)
87.58	1.1140	3.5	(3,0,-3)
89.34	1.0966	3.0	(5,4,-5)
89.89	1.0913	19.1	(3,-1,-2)

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Energy Properties

Formation Energy/atom

-0.51599

eV/atom

Energy/atom

-6.97394

eV/atom

Energy above Hull

0.0000

eV/atom

Uncorrected Energy

-6.9739

eV/atom

Volume/atom

10.78

Å³

c/a Ratio

1.0000

Electronic Properties

Metallic

Metal

Band Gap

Direct Gap

CBM

N/A

Magnetic Properties

Magnetic

Total Mag. Moment

0.0033

μB

Mag. Ordering

Mag. Sites

Magnetization/Volume

0.000050

μB/Å³

Elastic Properties

K_VRH

157.954

GPa

G_VRH

64.680

GPa

Young's Modulus E

170.735

GPa

Poisson Ratio ν

0.320

Pugh Ratio K/G

2.442

Vickers Hardness Est.

5.066

GPa

Ductility

Brittle

Anisotropy

0.756

Lame λ

114.834

GPa

Feature Analysis

Composition Overview

Element Composition (atomic fraction)

Composition Info

Major / Matrix Element

Ni · 0.333

Element Family

3d-TM

Solute Fraction

0.667

Interstitial Fraction

0.500

High-Entropy Alloy Features

Composite Radar (normalized)

Element-Class Share

Mix Entropy ΔS/R

1.3297

HEA criterion (>1.0 = high entropy)

Mix Entropy ΔS

11.0548

J/mol·K

Ω Parameter

0.6506

Ω > 1.1 favors solid solution

Atomic Size Mismatch δr

28.906%

δr < 6.6% favors single-phase solid solution

Electronegativity Diff Δχ

0.3868

smaller = more stable mixing

VEC

6.833

valence electron concentration, affects phase stability

Mix Enthalpy ΔH_mix

-38.829

kJ/mol; negative = exothermic mixing

Entropy Norm

0.9591

SS Former

Phase Tendency

Elasticity Features

Elastic Modulus Comparison (GPa)

Elastic Features

Elastic Anisotropy A^U

0.7560

Homogeneous Poisson ν

0.3200

Debye Temperature

544.9

Sound Velocity

3,162.3

m/s

Homogeneity

0.3200

Related Tasks

Related computation task IDs (5)

aaaddxdt aaadmkqq aaaeuigv aaafadds aaafbwdn

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-6646

Reference Citation

The crystal structure and related material properties of HoNi2B2C were obtained from the Materials Project database (MP-ID: mp-6646, 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_HoNi2B2C
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.76032203
_cell_length_b   5.76032203
_cell_length_c   5.76032203
_cell_angle_alpha   144.31581878
_cell_angle_beta   144.31581878
_cell_angle_gamma   51.35529326
_symmetry_Int_Tables_number   1
_chemical_formula_structural   HoNi2B2C
_chemical_formula_sum   'Ho1 Ni2 B2 C1'
_cell_volume   64.68537906
_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  0.00000000  0.00000000  0.00000000  1.0
  Ni  Ni1  1  0.75000000  0.25000000  0.50000000  1.0
  Ni  Ni2  1  0.25000000  0.75000000  0.50000000  1.0
  B  B3  1  0.35648100  0.35648100  0.00000000  1.0
  B  B4  1  0.64351900  0.64351900  0.00000000  1.0
  C  C5  1  0.50000000  0.50000000  0.00000000  1.0

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