HfMg6CoO8

High-Entropy Materials HEA

MP-ID: mp-1031738 · Space group: P4/mmm (#123)

Materials Project API

Basic Information

Formula

HfMg6CoO8

MP-ID

mp-1031738

Elements

Sites

Density

5.0971

g/cm³

Volume

166.56

Å³

Cell a

8.8509

Cell b

4.3380

Cell c

4.3380

α Angle

90.00

β Angle

90.00

γ Angle

90.00

Space Group

P4/mmm

Point Group

4/mmm

Crystal System

Tetragonal

Bravais Lattice

Stability

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
9.99	8.8509	55.7	(1,0,0)
20.06	4.4254	43.9	(2,0,0)
20.47	4.3380	80.0	(0,1,0)
22.83	3.8953	47.7	(1,1,0)
28.82	3.0979	70.3	(2,1,0)
29.11	3.0674	34.0	(0,1,1)
30.29	2.9503	8.9	(3,0,0)
30.85	2.8983	28.5	(1,1,1)
35.61	2.5210	76.1	(2,1,1)
36.84	2.4396	11.3	(3,1,0)
40.78	2.2127	50.0	(4,0,0)
41.64	2.1690	100.0	(0,2,0)
42.51	2.1264	3.0	(3,1,1)
42.93	2.1067	7.5	(1,2,0)
46.05	1.9711	19.0	(4,1,0)
46.63	1.9476	19.6	(2,2,0)
46.83	1.9400	18.6	(0,2,1)
48.01	1.8950	14.0	(1,2,1)
50.88	1.7945	16.4	(4,1,1)
51.43	1.7768	28.3	(2,2,1)
52.35	1.7475	8.3	(3,2,0)
56.12	1.6390	5.3	(5,1,0)
56.80	1.6210	7.2	(3,2,1)
59.70	1.5489	58.5	(4,2,0)

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Energy Properties

Formation Energy/atom

-2.68585

eV/atom

Energy/atom

-6.83942

eV/atom

Energy above Hull

0.3466

eV/atom

Uncorrected Energy

-6.3935

eV/atom

Volume/atom

10.41

Å³

c/a Ratio

0.4901

Electronic Properties

Metallic

Metal

Band Gap

Direct Gap

CBM

N/A

Magnetic Properties

Magnetic

Yes

Total Mag. Moment

1.9263

μB

Mag. Ordering

Mag. Sites

Magnetization/Volume

0.011570

μB/Å³

Elastic Properties

Elastic data not available

Feature Analysis

Composition Overview

Element Composition (atomic fraction)

Composition Info

Major / Matrix Element

O · 0.500

Element Family

Metalloid-Nonmetal

Solute Fraction

0.500

Interstitial Fraction

0.000

High-Entropy Alloy Features

Composite Radar (normalized)

Element-Class Share

Mix Entropy ΔS/R

1.0610

HEA criterion (>1.0 = high entropy)

Mix Entropy ΔS

8.8208

J/mol·K

Ω Parameter

1.2978

Ω > 1.1 favors solid solution

Atomic Size Mismatch δr

44.957%

δr < 6.6% favors single-phase solid solution

Electronegativity Diff Δχ

1.0386

smaller = more stable mixing

VEC

3.563

valence electron concentration, affects phase stability

Mix Enthalpy ΔH_mix

-4.354

kJ/mol; negative = exothermic mixing

Entropy Norm

0.7653

SS Former

Phase Tendency

Related Tasks

Related computation task IDs (2)

aaacgsgg aaacgsjp

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-1031738

Reference Citation

The crystal structure and related material properties of HfMg6CoO8 were obtained from the Materials Project database (MP-ID: mp-1031738, 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

Loading 3D structure…

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Raw CIF Data

# generated using pymatgen
data_HfMg6CoO8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.85085487
_cell_length_b   4.33798092
_cell_length_c   4.33798092
_cell_angle_alpha   90.00000000
_cell_angle_beta   90.00000000
_cell_angle_gamma   90.00000000
_symmetry_Int_Tables_number   1
_chemical_formula_structural   HfMg6CoO8
_chemical_formula_sum   'Hf1 Mg6 Co1 O8'
_cell_volume   166.55608140
_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
  Hf  Hf0  1  0.50000000  0.00000000  -0.00000000  1.0
  Mg  Mg1  1  0.00000000  0.50000000  0.50000000  1.0
  Mg  Mg2  1  0.50000000  0.50000000  0.50000000  1.0
  Mg  Mg3  1  0.22903232  0.00000000  0.50000000  1.0
  Mg  Mg4  1  0.77096768  0.00000000  0.50000000  1.0
  Mg  Mg5  1  0.22903232  0.50000000  -0.00000000  1.0
  Mg  Mg6  1  0.77096768  0.50000000  0.00000000  1.0
  Co  Co7  1  0.00000000  0.00000000  -0.00000000  1.0
  O  O8  1  0.26624017  0.00000000  0.00000000  1.0
  O  O9  1  0.73375983  0.00000000  -0.00000000  1.0
  O  O10  1  0.25038101  0.50000000  0.50000000  1.0
  O  O11  1  0.74961899  0.50000000  0.50000000  1.0
  O  O12  1  0.00000000  0.00000000  0.50000000  1.0
  O  O13  1  0.50000000  0.00000000  0.50000000  1.0
  O  O14  1  0.00000000  0.50000000  -0.00000000  1.0
  O  O15  1  0.50000000  0.50000000  -0.00000000  1.0

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