Na(FeO2)2

High-Entropy Materials HEA Traditional Materials TRA

MP-ID: mp-759691 · Space group: Pnma (#62)

Materials Project API

Basic Information

Formula

Na(FeO2)2

MP-ID

mp-759691

Elements

Sites

Density

4.3958

g/cm³

Volume

300.21

Å³

Cell a

2.9981

Cell b

9.2397

Cell c

10.8373

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
16.36	5.4186	13.1	(0,0,2)
18.99	4.6742	48.8	(0,1,2)
19.21	4.6199	67.0	(0,2,0)
25.33	3.5156	9.0	(0,2,2)
26.49	3.3644	2.3	(0,1,3)
30.17	2.9626	4.3	(0,3,1)
30.95	2.8895	2.7	(1,0,1)
31.44	2.8457	1.5	(0,2,3)
32.47	2.7578	2.1	(1,1,1)
33.06	2.7093	58.4	(0,0,4)
33.47	2.6776	100.0	(0,3,2)
34.50	2.5999	2.2	(0,1,4)
35.58	2.5236	94.7	(1,1,2)
35.70	2.5149	43.7	(1,2,0)
36.68	2.4498	1.5	(1,2,1)
38.41	2.3437	1.2	(0,3,3)
38.52	2.3371	4.3	(0,2,4)
39.04	2.3070	8.5	(1,0,3)
39.50	2.2812	4.0	(1,2,2)
39.90	2.2592	2.7	(0,4,1)
40.29	2.2383	22.1	(1,1,3)
42.54	2.1249	10.3	(0,4,2)
42.86	2.1102	4.5	(0,1,5)
42.92	2.1073	14.8	(1,3,1)

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Energy Properties

Formation Energy/atom

-1.60666

eV/atom

Energy/atom

-7.04575

eV/atom

Energy above Hull

0.0304

eV/atom

Uncorrected Energy

-6.0086

eV/atom

Volume/atom

10.72

Å³

c/a Ratio

3.6148

Electronic Properties

Metallic

Metal

Band Gap

Direct Gap

CBM

N/A

Magnetic Properties

Magnetic

Yes

Total Mag. Moment

35.9999

μB

Mag. Ordering

Mag. Sites

Magnetization/Volume

0.119920

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

0.462

Family

O-rich Multi-Component

Matrix Element

O · 0.571

Related Tasks

Related computation task IDs (2)

aaabtxbj aaadzelm

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-759691

Reference Citation

The crystal structure and related material properties of Na(FeO2)2 were obtained from the Materials Project database (MP-ID: mp-759691, 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   2.99806100
_cell_length_b   9.23974000
_cell_length_c   10.83727500
_cell_angle_alpha   90.00000000
_cell_angle_beta   90.00000000
_cell_angle_gamma   90.00000000
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Na(FeO2)2
_chemical_formula_sum   'Na4 Fe8 O16'
_cell_volume   300.20665087
_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  0.25000000  0.74262000  0.15743400  1.0
  Na  Na1  1  0.75000000  0.75738000  0.65743400  1.0
  Na  Na2  1  0.25000000  0.24262000  0.34256600  1.0
  Na  Na3  1  0.75000000  0.25738000  0.84256600  1.0
  Fe  Fe4  1  0.25000000  0.56297800  0.38801400  1.0
  Fe  Fe5  1  0.25000000  0.58353400  0.89725500  1.0
  Fe  Fe6  1  0.75000000  0.91646600  0.39725500  1.0
  Fe  Fe7  1  0.75000000  0.93702200  0.88801400  1.0
  Fe  Fe8  1  0.25000000  0.06297800  0.11198600  1.0
  Fe  Fe9  1  0.25000000  0.08353400  0.60274500  1.0
  Fe  Fe10  1  0.75000000  0.41646600  0.10274500  1.0
  Fe  Fe11  1  0.75000000  0.43702200  0.61198600  1.0
  O  O12  1  0.75000000  0.52370600  0.78545300  1.0
  O  O13  1  0.25000000  0.57538500  0.57395600  1.0
  O  O14  1  0.75000000  0.61418000  0.01983200  1.0
  O  O15  1  0.75000000  0.70512800  0.34932600  1.0
  O  O16  1  0.25000000  0.79487200  0.84932600  1.0
  O  O17  1  0.25000000  0.88582000  0.51983200  1.0
  O  O18  1  0.75000000  0.92461500  0.07395600  1.0
  O  O19  1  0.25000000  0.97629400  0.28545300  1.0
  O  O20  1  0.75000000  0.02370600  0.71454700  1.0
  O  O21  1  0.25000000  0.07538500  0.92604400  1.0
  O  O22  1  0.75000000  0.11418000  0.48016800  1.0
  O  O23  1  0.75000000  0.20512800  0.15067400  1.0
  O  O24  1  0.25000000  0.29487200  0.65067400  1.0
  O  O25  1  0.25000000  0.38582000  0.98016800  1.0
  O  O26  1  0.75000000  0.42461500  0.42604400  1.0
  O  O27  1  0.25000000  0.47629400  0.21454700  1.0

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