Mg6NbCoO8

High-Entropy Materials HEA

MP-ID: mp-1031981 · Space group: P4/mmm (#123)

Materials Project API

Basic Information

Formula

Mg6NbCoO8

MP-ID

mp-1031981

Elements

Sites

Density

4.3991

g/cm³

Volume

160.68

Å³

Cell a

8.7559

Cell b

4.2838

Cell c

4.2838

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
10.10	8.7559	79.9	(1,0,0)
20.28	4.3780	20.6	(2,0,0)
20.74	4.2838	3.8	(0,1,0)
23.11	3.8479	6.2	(1,1,0)
29.17	3.0618	3.2	(2,1,0)
29.49	3.0291	16.0	(0,1,1)
30.63	2.9186	10.6	(3,0,0)
31.25	2.8626	27.1	(1,1,1)
36.06	2.4910	53.1	(2,1,1)
37.28	2.4120	1.4	(3,1,0)
41.24	2.1890	53.0	(4,0,0)
42.19	2.1419	100.0	(0,2,0)
43.04	2.1018	11.3	(3,1,1)
43.50	2.0805	9.3	(1,2,0)
47.24	1.9240	8.5	(2,2,0)
48.65	1.8715	1.7	(1,2,1)
51.51	1.7742	6.3	(4,1,1)
52.11	1.7551	1.3	(2,2,1)
53.03	1.7268	8.3	(3,2,0)
60.47	1.5309	59.7	(4,2,0)
61.13	1.5161	3.8	(5,1,1)
61.20	1.5145	29.0	(0,2,2)
62.21	1.4924	3.1	(1,2,2)
65.18	1.4313	3.1	(2,2,2)

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Energy Properties

Formation Energy/atom

-2.57355

eV/atom

Energy/atom

-6.73613

eV/atom

Energy above Hull

0.2645

eV/atom

Uncorrected Energy

-6.2903

eV/atom

Volume/atom

10.04

Å³

c/a Ratio

0.4892

Electronic Properties

Metallic

Metal

Band Gap

Direct Gap

CBM

N/A

Magnetic Properties

Magnetic

Yes

Total Mag. Moment

3.3331

μB

Mag. Ordering

Mag. Sites

Magnetization/Volume

0.020740

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

1.6333

Ω > 1.1 favors solid solution

Atomic Size Mismatch δr

44.585%

δr < 6.6% favors single-phase solid solution

Electronegativity Diff Δχ

1.0210

smaller = more stable mixing

VEC

3.625

valence electron concentration, affects phase stability

Mix Enthalpy ΔH_mix

-3.542

kJ/mol; negative = exothermic mixing

Entropy Norm

0.7653

SS Former

Phase Tendency

Related Tasks

Related computation task IDs (2)

aaacgspp aaacgstk

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-1031981

Reference Citation

The crystal structure and related material properties of Mg6NbCoO8 were obtained from the Materials Project database (MP-ID: mp-1031981, 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_Mg6NbCoO8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.75591461
_cell_length_b   4.28375228
_cell_length_c   4.28375228
_cell_angle_alpha   90.00000000
_cell_angle_beta   90.00000000
_cell_angle_gamma   90.00000000
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Mg6NbCoO8
_chemical_formula_sum   'Mg6 Nb1 Co1 O8'
_cell_volume   160.67570522
_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
  Mg  Mg0  1  0.50000000  0.00000000  0.00000000  1.0
  Mg  Mg1  1  0.50000000  0.50000000  0.50000000  1.0
  Mg  Mg2  1  0.25524097  0.00000000  0.50000000  1.0
  Mg  Mg3  1  0.74475903  0.00000000  0.50000000  1.0
  Mg  Mg4  1  0.25524097  0.50000000  0.00000000  1.0
  Mg  Mg5  1  0.74475903  0.50000000  0.00000000  1.0
  Nb  Nb6  1  0.00000000  0.50000000  0.50000000  1.0
  Co  Co7  1  0.00000000  0.00000000  0.00000000  1.0
  O  O8  1  0.26146453  0.00000000  0.00000000  1.0
  O  O9  1  0.73853547  0.00000000  0.00000000  1.0
  O  O10  1  0.25751362  0.50000000  0.50000000  1.0
  O  O11  1  0.74248638  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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