Mg(NiO2)2

High-Entropy Materials HEA Traditional Materials TRA

MP-ID: mp-1047668 · Space group: Cmcm (#63)

Materials Project API

Basic Information

Formula

Mg(NiO2)2

MP-ID

mp-1047668

Elements

Sites

Density

5.2842

g/cm³

Volume

129.27

Å³

Cell a

4.9779

Cell b

4.9779

Cell c

9.3448

α Angle

90.00

β Angle

90.00

γ Angle

146.06

Space Group

Cmcm

Point Group

mmm

Crystal System

Orthorhombic

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
18.64	4.7612	1.5	(1,-1,0)
18.99	4.6724	49.5	(0,0,2)
20.94	4.2423	19.6	(1,-1,1)
26.73	3.3348	3.5	(1,-1,2)
32.21	2.7791	34.4	(1,0,0)
33.65	2.6638	19.4	(1,0,1)
34.41	2.6066	100.0	(1,-1,3)
37.66	2.3885	17.0	(1,0,2)
37.79	2.3806	21.5	(2,-2,0)
42.16	2.1432	41.8	(2,-1,0)
42.62	2.1211	6.5	(2,-2,2)
43.13	2.0973	12.9	(1,-1,4)
43.31	2.0890	40.8	(2,-1,1)
43.65	2.0737	13.3	(1,0,3)
46.62	1.9480	53.9	(2,-1,2)
51.07	1.7883	5.8	(1,0,4)
51.78	1.7656	11.9	(2,-1,3)
52.61	1.7397	13.1	(1,-1,5)
58.44	1.5793	3.5	(2,-1,4)
58.81	1.5702	6.5	(3,-2,1)
59.04	1.5647	1.1	(3,-3,1)
59.34	1.5575	12.2	(0,0,6)
59.62	1.5509	25.8	(1,0,5)
61.51	1.5076	11.6	(3,-2,2)

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Energy Properties

Formation Energy/atom

-1.50451

eV/atom

Energy/atom

-6.21630

eV/atom

Energy above Hull

0.0653

eV/atom

Uncorrected Energy

-5.0977

eV/atom

Volume/atom

9.23

Å³

c/a Ratio

1.8773

Electronic Properties

Metallic

Metal

Band Gap

Direct Gap

CBM

N/A

Magnetic Properties

Magnetic

Yes

Total Mag. Moment

4.0008

μB

Mag. Ordering

Mag. Sites

Magnetization/Volume

0.030950

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

0.519

Family

O-rich Multi-Component

Matrix Element

O · 0.571

Related Tasks

Related computation task IDs (2)

aaachpvt aaaecqjc

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-1047668

Reference Citation

The crystal structure and related material properties of Mg(NiO2)2 were obtained from the Materials Project database (MP-ID: mp-1047668, 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   4.97789309
_cell_length_b   4.97789309
_cell_length_c   9.34475300
_cell_angle_alpha   90.00000000
_cell_angle_beta   90.00000000
_cell_angle_gamma   146.06313743
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Mg(NiO2)2
_chemical_formula_sum   'Mg2 Ni4 O8'
_cell_volume   129.27372069
_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  0.60763500  0.39236500  0.75000000  1.0
  Mg  Mg1  1  0.39236500  0.60763500  0.25000000  1.0
  Ni  Ni2  1  0.13459400  0.86540600  0.06978600  1.0
  Ni  Ni3  1  0.86540600  0.13459400  0.93021400  1.0
  Ni  Ni4  1  0.13459400  0.86540600  0.43021400  1.0
  Ni  Ni5  1  0.86540600  0.13459400  0.56978600  1.0
  O  O6  1  0.77567300  0.22432700  0.38610500  1.0
  O  O7  1  0.22432700  0.77567300  0.61389500  1.0
  O  O8  1  0.22432700  0.77567300  0.88610500  1.0
  O  O9  1  0.77567300  0.22432700  0.11389500  1.0
  O  O10  1  0.04217600  0.95782400  0.25000000  1.0
  O  O11  1  0.95782400  0.04217600  0.75000000  1.0
  O  O12  1  0.50000000  0.50000000  0.00000000  1.0
  O  O13  1  0.50000000  0.50000000  0.50000000  1.0

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