Na3(NiO2)2

High-Entropy Materials HEA Traditional Materials TRA

MP-ID: mp-850400 · Space group: Pnma (#62)

Materials Project API

Basic Information

Formula

Na3(NiO2)2

MP-ID

mp-850400

Elements

Sites

Density

3.4562

g/cm³

Volume

481.14

Å³

Cell a

5.5517

Cell b

8.6074

Cell c

10.0685

α Angle

90.00

β Angle

90.00

γ Angle

90.00

Space Group

Pnma

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
13.53	6.5425	2.3	(0,1,1)
19.02	4.6655	100.0	(1,1,0)
20.64	4.3037	53.3	(0,2,0)
20.99	4.2331	6.9	(1,1,1)
26.20	3.4014	1.2	(1,2,0)
27.68	3.2225	1.3	(1,2,1)
28.55	3.1269	8.3	(0,1,3)
31.75	2.8184	4.4	(1,2,2)
32.25	2.7759	9.6	(2,0,0)
32.45	2.7593	1.0	(0,3,1)
33.49	2.6760	12.5	(2,0,1)
35.12	2.5554	6.9	(2,1,1)
35.21	2.5489	48.5	(1,3,0)
35.67	2.5171	7.1	(0,0,4)
36.36	2.4709	21.3	(1,3,1)
37.65	2.3890	11.6	(1,2,3)
38.48	2.3393	8.0	(2,1,2)
38.60	2.3327	7.5	(2,2,0)
39.66	2.2725	4.4	(2,2,1)
40.73	2.2153	23.1	(1,1,4)
41.56	2.1728	16.7	(0,2,4)
42.25	2.1390	7.4	(2,0,3)
43.60	2.0759	1.7	(2,1,3)
45.46	1.9950	2.5	(2,3,0)

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Energy Properties

Formation Energy/atom

-1.25568

eV/atom

Energy/atom

-5.18649

eV/atom

Energy above Hull

0.0977

eV/atom

Uncorrected Energy

-4.3165

eV/atom

Volume/atom

13.36

Å³

c/a Ratio

1.8136

Electronic Properties

Metallic

Metal

Band Gap

Direct Gap

CBM

N/A

Magnetic Properties

Magnetic

Yes

Total Mag. Moment

19.9995

μB

Mag. Ordering

Mag. Sites

Magnetization/Volume

0.041570

μB/Å³

Elastic Properties

Elastic data not available

Feature Analysis

Composition Overview

Element Composition (atomic fraction)

Composition Info

Major / Matrix Element

O · 0.444

Element Family

Metalloid-Nonmetal

Solute Fraction

0.556

Interstitial Fraction

0.000

High-Entropy Alloy Features

Composite Radar (normalized)

Element-Class Share

Mix Entropy ΔS/R

1.0609

HEA criterion (>1.0 = high entropy)

Mix Entropy ΔS

8.8200

J/mol·K

Ω Parameter

0.6558

Ω > 1.1 favors solid solution

Atomic Size Mismatch δr

47.450%

δr < 6.6% favors single-phase solid solution

Electronegativity Diff Δχ

1.1116

smaller = more stable mixing

VEC

4.333

valence electron concentration, affects phase stability

Mix Enthalpy ΔH_mix

-7.155

kJ/mol; negative = exothermic mixing

Entropy Norm

0.9656

SS Former

Phase Tendency

Traditional Material Features

ROM Blended-Feature Radar

Rating & Classification

Tier

Score

0.369

Family

O-rich Multi-Component

Matrix Element

O · 0.444

Related Tasks

Related computation task IDs (2)

aaabzmbz aaadzwbm

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-850400

Reference Citation

The crystal structure and related material properties of Na3(NiO2)2 were obtained from the Materials Project database (MP-ID: mp-850400, 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_Na3(NiO2)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.55173600
_cell_length_b   8.60744100
_cell_length_c   10.06851300
_cell_angle_alpha   90.00000000
_cell_angle_beta   90.00000000
_cell_angle_gamma   90.00000000
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Na3(NiO2)2
_chemical_formula_sum   'Na12 Ni8 O16'
_cell_volume   481.13637934
_cell_formula_units_Z   4
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
  Na  Na0  1  0.05425700  0.14922700  0.09695200  1.0
  Na  Na1  1  0.05425700  0.14922700  0.40304800  1.0
  Na  Na2  1  0.15196500  0.82534600  0.25000000  1.0
  Na  Na3  1  0.34803500  0.32534600  0.75000000  1.0
  Na  Na4  1  0.44574300  0.64922700  0.90304800  1.0
  Na  Na5  1  0.44574300  0.64922700  0.59695200  1.0
  Na  Na6  1  0.55425700  0.35077300  0.09695200  1.0
  Na  Na7  1  0.55425700  0.35077300  0.40304800  1.0
  Na  Na8  1  0.65196500  0.67465400  0.25000000  1.0
  Na  Na9  1  0.84803500  0.17465400  0.75000000  1.0
  Na  Na10  1  0.94574300  0.85077300  0.59695200  1.0
  Na  Na11  1  0.94574300  0.85077300  0.90304800  1.0
  Ni  Ni12  1  0.05910000  0.48673400  0.12251800  1.0
  Ni  Ni13  1  0.05910000  0.48673400  0.37748200  1.0
  Ni  Ni14  1  0.44090000  0.98673400  0.87748200  1.0
  Ni  Ni15  1  0.44090000  0.98673400  0.62251800  1.0
  Ni  Ni16  1  0.55910000  0.01326600  0.12251800  1.0
  Ni  Ni17  1  0.55910000  0.01326600  0.37748200  1.0
  Ni  Ni18  1  0.94090000  0.51326600  0.62251800  1.0
  Ni  Ni19  1  0.94090000  0.51326600  0.87748200  1.0
  O  O20  1  0.10956800  0.64134200  0.75000000  1.0
  O  O21  1  0.19071100  0.39627400  0.53319400  1.0
  O  O22  1  0.19071100  0.39627400  0.96680600  1.0
  O  O23  1  0.22109200  0.06490000  0.75000000  1.0
  O  O24  1  0.27890800  0.56490000  0.25000000  1.0
  O  O25  1  0.30928900  0.89627400  0.03319400  1.0
  O  O26  1  0.30928900  0.89627400  0.46680600  1.0
  O  O27  1  0.39043200  0.14134200  0.25000000  1.0
  O  O28  1  0.60956800  0.85865800  0.75000000  1.0
  O  O29  1  0.69071100  0.10372600  0.53319400  1.0
  O  O30  1  0.69071100  0.10372600  0.96680600  1.0
  O  O31  1  0.72109200  0.43510000  0.75000000  1.0
  O  O32  1  0.77890800  0.93510000  0.25000000  1.0
  O  O33  1  0.80928900  0.60372600  0.03319400  1.0
  O  O34  1  0.80928900  0.60372600  0.46680600  1.0
  O  O35  1  0.89043200  0.35865800  0.25000000  1.0

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