Na3(CoO2)2

High-Entropy Materials HEA Traditional Materials TRA

MP-ID: mp-760235 · Space group: Pnma (#62)

Materials Project API

Basic Information

Formula

Na3(CoO2)2

MP-ID

mp-760235

Elements

Sites

Density

3.4022

g/cm³

Volume

489.70

Å³

Cell a

5.6394

Cell b

8.6042

Cell c

10.0923

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
13.52	6.5476	2.7	(0,1,1)
18.81	4.7166	100.0	(1,1,0)
20.65	4.3021	56.8	(0,2,0)
20.79	4.2730	3.0	(1,1,1)
26.05	3.4205	1.4	(1,2,0)
27.24	3.2738	1.5	(0,2,2)
28.49	3.1331	8.6	(0,1,3)
31.60	2.8313	6.5	(1,2,2)
31.73	2.8197	13.9	(2,0,0)
32.45	2.7588	1.6	(0,3,1)
32.98	2.7157	8.3	(2,0,1)
34.64	2.5898	6.5	(2,1,1)
35.10	2.5565	54.9	(1,3,0)
35.58	2.5231	7.0	(0,0,4)
36.25	2.4782	17.3	(1,3,1)
37.50	2.3985	12.0	(1,2,3)
38.02	2.3666	7.8	(2,1,2)
38.16	2.3583	9.4	(2,2,0)
39.23	2.2964	1.7	(2,2,1)
40.55	2.2248	22.8	(1,1,4)
41.49	2.1764	15.6	(0,2,4)
41.80	2.1610	4.4	(2,0,3)
43.16	2.0959	3.6	(2,1,3)
45.09	2.0107	1.7	(2,3,0)

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Energy Properties

Formation Energy/atom

-1.40466

eV/atom

Energy/atom

-5.63620

eV/atom

Energy above Hull

0.0978

eV/atom

Uncorrected Energy

-4.9669

eV/atom

Volume/atom

13.60

Å³

c/a Ratio

1.7896

Electronic Properties

Metallic

Metal

Band Gap

Direct Gap

CBM

N/A

Magnetic Properties

Magnetic

Yes

Total Mag. Moment

27.9994

μB

Mag. Ordering

Mag. Sites

Magnetization/Volume

0.057180

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

1.0281

Ω > 1.1 favors solid solution

Atomic Size Mismatch δr

47.388%

δr < 6.6% favors single-phase solid solution

Electronegativity Diff Δχ

1.1138

smaller = more stable mixing

VEC

4.111

valence electron concentration, affects phase stability

Mix Enthalpy ΔH_mix

-4.641

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 (1)

aaadzuts

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-760235

Reference Citation

The crystal structure and related material properties of Na3(CoO2)2 were obtained from the Materials Project database (MP-ID: mp-760235, 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

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Raw CIF Data

# generated using pymatgen
data_Na3(CoO2)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.63940200
_cell_length_b   8.60423700
_cell_length_c   10.09227200
_cell_angle_alpha   90.00000000
_cell_angle_beta   90.00000000
_cell_angle_gamma   90.00000000
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Na3(CoO2)2
_chemical_formula_sum   'Na12 Co8 O16'
_cell_volume   489.70480477
_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  0.03905900  0.14614800  0.10094000  1.0
  Na  Na1  1  0.03905900  0.14614800  0.39906000  1.0
  Na  Na2  1  0.13736600  0.82207000  0.25000000  1.0
  Na  Na3  1  0.36263400  0.32207000  0.75000000  1.0
  Na  Na4  1  0.46094100  0.64614800  0.89906000  1.0
  Na  Na5  1  0.46094100  0.64614800  0.60094000  1.0
  Na  Na6  1  0.53905900  0.35385200  0.10094000  1.0
  Na  Na7  1  0.53905900  0.35385200  0.39906000  1.0
  Na  Na8  1  0.63736600  0.67793000  0.25000000  1.0
  Na  Na9  1  0.86263400  0.17793000  0.75000000  1.0
  Na  Na10  1  0.96094100  0.85385200  0.60094000  1.0
  Na  Na11  1  0.96094100  0.85385200  0.89906000  1.0
  Co  Co12  1  0.04429400  0.48689600  0.11947200  1.0
  Co  Co13  1  0.04429400  0.48689600  0.38052800  1.0
  Co  Co14  1  0.45570600  0.98689600  0.88052800  1.0
  Co  Co15  1  0.45570600  0.98689600  0.61947200  1.0
  Co  Co16  1  0.54429400  0.01310400  0.11947200  1.0
  Co  Co17  1  0.54429400  0.01310400  0.38052800  1.0
  Co  Co18  1  0.95570600  0.51310400  0.61947200  1.0
  Co  Co19  1  0.95570600  0.51310400  0.88052800  1.0
  O  O20  1  0.12552400  0.63631800  0.75000000  1.0
  O  O21  1  0.20361600  0.39917200  0.53221200  1.0
  O  O22  1  0.20361600  0.39917200  0.96778800  1.0
  O  O23  1  0.22829200  0.05693800  0.75000000  1.0
  O  O24  1  0.27170800  0.55693800  0.25000000  1.0
  O  O25  1  0.29638400  0.89917200  0.03221200  1.0
  O  O26  1  0.29638400  0.89917200  0.46778800  1.0
  O  O27  1  0.37447600  0.13631800  0.25000000  1.0
  O  O28  1  0.62552400  0.86368200  0.75000000  1.0
  O  O29  1  0.70361600  0.10082800  0.53221200  1.0
  O  O30  1  0.70361600  0.10082800  0.96778800  1.0
  O  O31  1  0.72829200  0.44306200  0.75000000  1.0
  O  O32  1  0.77170800  0.94306200  0.25000000  1.0
  O  O33  1  0.79638400  0.60082800  0.03221200  1.0
  O  O34  1  0.79638400  0.60082800  0.46778800  1.0
  O  O35  1  0.87447600  0.36368200  0.25000000  1.0

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