Na(FeO2)2

High-Entropy Materials HEA Traditional Materials TRA

MP-ID: mp-849436 · Space group: Pmmn (#59)

Materials Project API

Basic Information

Formula

Na(FeO2)2

MP-ID

mp-849436

Elements

Sites

Density

4.1975

g/cm³

Volume

314.39

Å³

Cell a

4.8766

Cell b

5.6336

Cell c

11.4436

α Angle

90.01

β Angle

89.99

γ Angle

90.00

Space Group

Pmmn

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
15.49	5.7218	100.0	(0,0,2)
31.27	2.8609	11.1	(0,0,4)
36.85	2.4392	5.6	(1,-2,0)
36.85	2.4391	5.6	(1,2,0)
36.86	2.4383	6.2	(2,0,0)
40.19	2.2440	5.4	(1,-2,2)
40.19	2.2438	5.4	(1,2,2)
40.19	2.2437	5.4	(1,2,-2)
40.19	2.2436	5.4	(1,-2,-2)
40.20	2.2433	4.9	(2,0,2)
40.21	2.2429	4.9	(2,0,-2)
44.06	2.0552	1.5	(1,-2,3)
44.07	2.0549	1.5	(1,2,3)
44.07	2.0549	1.5	(1,2,-3)
44.07	2.0548	1.5	(1,-2,-3)
44.07	2.0547	2.0	(2,0,3)
44.08	2.0542	2.0	(2,0,-3)
49.07	1.8564	5.8	(1,-2,4)
49.08	1.8561	5.8	(1,2,4)
49.08	1.8561	5.8	(1,2,-4)
49.09	1.8560	6.2	(2,0,4)
49.09	1.8559	5.8	(1,-2,-4)
49.10	1.8555	6.2	(2,0,-4)
61.73	1.5027	2.7	(1,-2,6)

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Energy Properties

Formation Energy/atom

-1.47452

eV/atom

Energy/atom

-6.91360

eV/atom

Energy above Hull

0.1625

eV/atom

Uncorrected Energy

-5.8765

eV/atom

Volume/atom

11.23

Å³

c/a Ratio

2.3466

Electronic Properties

Metallic

Metal

Band Gap

Direct Gap

CBM

N/A

Magnetic Properties

Magnetic

Yes

Total Mag. Moment

36.0002

μB

Mag. Ordering

Mag. Sites

Magnetization/Volume

0.114510

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

0.374

Family

O-rich Multi-Component

Matrix Element

O · 0.571

Related Tasks

Related computation task IDs (1)

aaadyubb

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-849436

Reference Citation

The crystal structure and related material properties of Na(FeO2)2 were obtained from the Materials Project database (MP-ID: mp-849436, 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   4.87663805
_cell_length_b   5.63360102
_cell_length_c   11.44362409
_cell_angle_alpha   90.00701890
_cell_angle_beta   89.98528238
_cell_angle_gamma   90.00346771
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Na(FeO2)2
_chemical_formula_sum   'Na4 Fe8 O16'
_cell_volume   314.39104996
_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  0.03092300  0.75002600  0.25011300  1.0
  Na  Na1  1  0.35906200  0.75016100  0.74997100  1.0
  Na  Na2  1  0.64087700  0.24985100  0.24991900  1.0
  Na  Na3  1  0.96966200  0.24997400  0.74992700  1.0
  Fe  Fe4  1  0.00361100  0.24990900  0.00355100  1.0
  Fe  Fe5  1  0.99640200  0.75014100  0.99618000  1.0
  Fe  Fe6  1  0.00378900  0.25000300  0.49633400  1.0
  Fe  Fe7  1  0.99612000  0.74999800  0.50374600  1.0
  Fe  Fe8  1  0.49977300  0.49945700  0.99988500  1.0
  Fe  Fe9  1  0.49981100  0.00046900  0.99987700  1.0
  Fe  Fe10  1  0.49984500  0.99991100  0.50007800  1.0
  Fe  Fe11  1  0.49984300  0.50007900  0.50008300  1.0
  O  O12  1  0.16591000  0.00087000  0.59047100  1.0
  O  O13  1  0.16610800  0.00060500  0.90944000  1.0
  O  O14  1  0.16591700  0.49920300  0.59046900  1.0
  O  O15  1  0.16615900  0.49953200  0.90943500  1.0
  O  O16  1  0.33793800  0.24994800  0.09060400  1.0
  O  O17  1  0.33775700  0.24996100  0.40947100  1.0
  O  O18  1  0.32824800  0.74998300  0.08649100  1.0
  O  O19  1  0.32851000  0.74996100  0.41372400  1.0
  O  O20  1  0.67153300  0.25003400  0.58653500  1.0
  O  O21  1  0.67164100  0.24996000  0.91352100  1.0
  O  O22  1  0.66227500  0.75003800  0.58983200  1.0
  O  O23  1  0.66248000  0.74999100  0.91004800  1.0
  O  O24  1  0.83408600  0.99851800  0.40950100  1.0
  O  O25  1  0.83407800  0.50139900  0.40950000  1.0
  O  O26  1  0.83385100  0.99834500  0.09064600  1.0
  O  O27  1  0.83379000  0.50167100  0.09065000  1.0

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