Mg(NiO2)2

High-Entropy Materials HEA Traditional Materials TRA

MP-ID: mp-1040809 · Space group: R3m (#160)

Materials Project API

Basic Information

Formula

Mg(NiO2)2

MP-ID

mp-1040809

Elements

Sites

Density

4.7714

g/cm³

Volume

143.17

Å³

Cell a

5.8681

Cell b

5.8681

Cell c

5.8681

α Angle

60.09

β Angle

60.09

γ Angle

60.09

Space Group

R3m

Point Group

Crystal System

Trigonal

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
18.50	4.7966	15.1	(1,0,0)
18.53	4.7880	64.0	(1,1,1)
21.40	4.1521	25.1	(1,1,0)
30.42	2.9380	5.7	(1,0,-1)
30.42	2.9380	2.9	(1,-1,0)
30.47	2.9340	50.0	(2,1,1)
35.84	2.5054	100.0	(1,1,-1)
35.86	2.5041	89.8	(2,1,0)
35.90	2.5017	39.4	(2,2,1)
37.50	2.3983	19.9	(2,0,0)
37.57	2.3940	3.6	(2,2,2)
43.60	2.0761	21.9	(2,2,0)
43.60	2.0761	43.8	(2,0,2)
47.71	1.9063	2.7	(2,0,-1)
47.75	1.9047	3.7	(3,1,1)
47.79	1.9031	3.8	(3,2,2)
49.03	1.8579	2.0	(2,1,-1)
49.09	1.8559	8.5	(3,2,1)
54.06	1.6962	1.4	(2,-1,-1)
54.09	1.6955	15.9	(3,1,0)
54.17	1.6932	1.6	(3,3,2)
57.65	1.5989	22.2	(3,0,0)
57.68	1.5982	27.9	(3,2,0)
57.72	1.5973	26.2	(3,3,1)

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Energy Properties

Formation Energy/atom

-1.51936

eV/atom

Energy/atom

-6.23115

eV/atom

Energy above Hull

0.0504

eV/atom

Uncorrected Energy

-5.1126

eV/atom

Volume/atom

10.23

Å³

c/a Ratio

1.0000

Electronic Properties

Metallic

Metal

Band Gap

Direct Gap

CBM

N/A

Magnetic Properties

Magnetic

Yes

Total Mag. Moment

0.0000

μB

Mag. Ordering

FiM

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

O · 0.571

Element Family

Metalloid-Nonmetal

Solute Fraction

0.429

Interstitial Fraction

0.000

High-Entropy Alloy Features

Composite Radar (normalized)

Element-Class Share

Mix Entropy ΔS/R

0.9557

HEA criterion (>1.0 = high entropy)

Mix Entropy ΔS

7.9457

J/mol·K

Ω Parameter

1.5984

Ω > 1.1 favors solid solution

Atomic Size Mismatch δr

42.364%

δr < 6.6% favors single-phase solid solution

Electronegativity Diff Δχ

0.8759

smaller = more stable mixing

VEC

5.429

valence electron concentration, affects phase stability

Mix Enthalpy ΔH_mix

-3.265

kJ/mol; negative = exothermic mixing

Entropy Norm

0.8699

SS Former

Phase Tendency

Traditional Material Features

ROM Blended-Feature Radar

Rating & Classification

Tier

Score

0.529

Family

O-rich Multi-Component

Matrix Element

O · 0.571

Related Tasks

Related computation task IDs (2)

aaachfro aaadwyae

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-1040809

Reference Citation

The crystal structure and related material properties of Mg(NiO2)2 were obtained from the Materials Project database (MP-ID: mp-1040809, 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_Mg(NiO2)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.86804736
_cell_length_b   5.86804736
_cell_length_c   5.86804754
_cell_angle_alpha   60.08919134
_cell_angle_beta   60.08919134
_cell_angle_gamma   60.08918628
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Mg(NiO2)2
_chemical_formula_sum   'Mg2 Ni4 O8'
_cell_volume   143.16691756
_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
  Mg  Mg0  1  0.00874200  0.00874200  0.00874200  1.0
  Mg  Mg1  1  0.62532500  0.62532500  0.62532500  1.0
  Ni  Ni2  1  0.24344600  0.24344600  0.24344600  1.0
  Ni  Ni3  1  0.62966400  0.11722800  0.62966400  1.0
  Ni  Ni4  1  0.62966400  0.62966400  0.11722800  1.0
  Ni  Ni5  1  0.11722800  0.62966400  0.62966400  1.0
  O  O6  1  0.84337500  0.37534000  0.37534000  1.0
  O  O7  1  0.37534000  0.37534000  0.84337500  1.0
  O  O8  1  0.37534000  0.84337500  0.37534000  1.0
  O  O9  1  0.37047300  0.37047300  0.37047300  1.0
  O  O10  1  0.87362900  0.87362900  0.87362900  1.0
  O  O11  1  0.86922600  0.41932100  0.86922600  1.0
  O  O12  1  0.86922600  0.86922600  0.41932100  1.0
  O  O13  1  0.41932100  0.86922600  0.86922600  1.0

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