Na(FeO2)2

High-Entropy Materials HEA Traditional Materials TRA

MP-ID: mp-764034 · Space group: Imma (#74)

Materials Project API

Basic Information

Formula

Na(FeO2)2

MP-ID

mp-764034

Elements

Sites

Density

4.0813

g/cm³

Volume

161.67

Å³

Cell a

6.1126

Cell b

6.1126

Cell c

6.1126

α Angle

120.66

β Angle

119.18

γ Angle

90.15

Space Group

Imma

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
17.63	5.0298	100.0	(1,0,0)
17.90	4.9556	74.2	(0,1,0)
28.85	3.0943	3.9	(1,-1,1)
29.22	3.0559	13.1	(1,1,0)
29.52	3.0260	2.9	(1,-1,-1)
34.16	2.6247	56.3	(1,0,1)
34.37	2.6094	25.2	(2,1,-1)
34.51	2.5989	28.7	(1,2,-1)
34.59	2.5929	54.2	(0,1,1)
35.70	2.5149	16.8	(2,0,0)
36.25	2.4778	14.6	(0,2,0)
41.75	2.1635	67.1	(0,0,2)
41.86	2.1583	32.6	(2,2,-2)
45.19	2.0064	1.3	(2,-1,1)
45.58	1.9901	4.4	(2,1,0)
45.92	1.9761	1.5	(1,2,0)
46.21	1.9644	1.7	(1,-2,-1)
51.36	1.7790	1.6	(2,0,1)
52.19	1.7528	1.2	(0,2,1)
54.75	1.6766	2.1	(3,0,0)
54.91	1.6722	26.6	(1,0,2)
55.23	1.6631	13.8	(3,2,-2)
55.33	1.6604	10.1	(2,3,-2)
55.40	1.6584	21.2	(0,1,2)

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Energy Properties

Formation Energy/atom

-1.54417

eV/atom

Energy/atom

-6.98326

eV/atom

Energy above Hull

0.0929

eV/atom

Uncorrected Energy

-5.9461

eV/atom

Volume/atom

11.55

Å³

c/a Ratio

1.0000

Electronic Properties

Metallic

Metal

Band Gap

Direct Gap

CBM

N/A

Magnetic Properties

Magnetic

Yes

Total Mag. Moment

17.9946

μB

Mag. Ordering

Mag. Sites

Magnetization/Volume

0.111300

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

10.4549

Ω > 1.1 favors solid solution

Atomic Size Mismatch δr

47.919%

δr < 6.6% favors single-phase solid solution

Electronegativity Diff Δχ

0.9852

smaller = more stable mixing

VEC

4.714

valence electron concentration, affects phase stability

Mix Enthalpy ΔH_mix

0.457

kJ/mol; negative = exothermic mixing

Entropy Norm

0.8699

SS Former

Phase Tendency

Traditional Material Features

ROM Blended-Feature Radar

Rating & Classification

Tier

Score

0.420

Family

O-rich Multi-Component

Matrix Element

O · 0.571

Related Tasks

Related computation task IDs (3)

aaabzbnm aaaduvmk aaaefjtq

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-764034

Reference Citation

The crystal structure and related material properties of Na(FeO2)2 were obtained from the Materials Project database (MP-ID: mp-764034, 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_Na(FeO2)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.11263208
_cell_length_b   6.11263208
_cell_length_c   6.11263208
_cell_angle_alpha   120.65505962
_cell_angle_beta   119.17544272
_cell_angle_gamma   90.15161601
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Na(FeO2)2
_chemical_formula_sum   'Na2 Fe4 O8'
_cell_volume   161.67164691
_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
  Na  Na0  1  0.87455800  0.12455800  0.75000000  1.0
  Na  Na1  1  0.12544200  0.87544200  0.25000000  1.0
  Fe  Fe2  1  0.00000000  0.50000000  0.50000000  1.0
  Fe  Fe3  1  0.50000000  0.00000000  0.00000000  1.0
  Fe  Fe4  1  0.50000000  0.50000000  0.00000000  1.0
  Fe  Fe5  1  0.50000000  0.50000000  0.50000000  1.0
  O  O6  1  0.72214700  0.25234600  0.03019900  1.0
  O  O7  1  0.71602200  0.26220300  0.45381900  1.0
  O  O8  1  0.72214700  0.69194700  0.46980100  1.0
  O  O9  1  0.30838400  0.26220300  0.04618100  1.0
  O  O10  1  0.69161600  0.73779700  0.95381900  1.0
  O  O11  1  0.27785300  0.30805300  0.53019900  1.0
  O  O12  1  0.27785300  0.74765400  0.96980100  1.0
  O  O13  1  0.28397800  0.73779700  0.54618100  1.0

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