Na(FeO2)2

High-Entropy Materials HEA Traditional Materials TRA

MP-ID: mp-850232 · Space group: P1 (#1)

Materials Project API

Basic Information

Formula

Na(FeO2)2

MP-ID

mp-850232

Elements

Sites

Density

3.8028

g/cm³

Volume

347.02

Å³

Cell a

5.1141

Cell b

5.8998

Cell c

11.5013

α Angle

90.13

β Angle

90.05

γ Angle

90.08

Space Group

Point Group

Crystal System

Triclinic

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
15.41	5.7507	100.0	(0,0,2)
31.10	2.8753	10.9	(0,0,4)
35.09	2.5571	7.2	(2,0,0)
35.10	2.5568	6.5	(1,-2,0)
35.14	2.5538	6.4	(1,2,0)
38.51	2.3376	6.3	(1,-2,2)
38.52	2.3373	5.7	(2,0,-2)
38.54	2.3362	6.1	(1,2,-2)
38.54	2.3357	5.7	(2,0,2)
38.56	2.3349	6.1	(1,-2,-2)
38.61	2.3319	6.1	(1,2,2)
42.47	2.1287	1.7	(1,-2,3)
42.48	2.1282	2.3	(2,0,-3)
42.48	2.1279	1.7	(1,2,-3)
42.51	2.1264	2.2	(2,0,3)
42.53	2.1256	1.7	(1,-2,-3)
42.58	2.1230	1.7	(1,2,3)
47.55	1.9122	6.4	(1,-2,4)
47.56	1.9118	6.6	(1,2,-4)
47.57	1.9116	6.7	(2,0,-4)
47.61	1.9099	6.9	(2,0,4)
47.63	1.9091	6.4	(1,-2,-4)
47.69	1.9071	6.4	(1,2,4)
60.30	1.5349	2.9	(1,2,-6)

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Energy Properties

Formation Energy/atom

-1.58371

eV/atom

Energy/atom

-7.02279

eV/atom

Energy above Hull

0.0533

eV/atom

Uncorrected Energy

-5.9857

eV/atom

Volume/atom

12.39

Å³

c/a Ratio

2.2490

Electronic Properties

Metallic

Metal

Band Gap

Direct Gap

CBM

N/A

Magnetic Properties

Magnetic

Yes

Total Mag. Moment

36.0001

μB

Mag. Ordering

Mag. Sites

Magnetization/Volume

0.103740

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

0.447

Family

O-rich Multi-Component

Matrix Element

O · 0.571

Related Tasks

Related computation task IDs (1)

aaaeasif

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-850232

Reference Citation

The crystal structure and related material properties of Na(FeO2)2 were obtained from the Materials Project database (MP-ID: mp-850232, 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_Na(FeO2)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.11409900
_cell_length_b   5.89984421
_cell_length_c   11.50133011
_cell_angle_alpha   90.13426322
_cell_angle_beta   90.05069343
_cell_angle_gamma   90.07617629
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Na(FeO2)2
_chemical_formula_sum   'Na4 Fe8 O16'
_cell_volume   347.02119143
_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  0.96740200  0.75055600  0.74951600  1.0
  Na  Na1  1  0.64293300  0.75129000  0.25067600  1.0
  Na  Na2  1  0.35670100  0.24836400  0.75004600  1.0
  Na  Na3  1  0.02841300  0.24987100  0.25031000  1.0
  Fe  Fe4  1  0.99807100  0.25269800  0.99570100  1.0
  Fe  Fe5  1  0.00265500  0.75147100  0.00657400  1.0
  Fe  Fe6  1  0.99790900  0.24958300  0.50709300  1.0
  Fe  Fe7  1  0.00216100  0.75034300  0.49329400  1.0
  Fe  Fe8  1  0.49994800  0.49757800  0.99972200  1.0
  Fe  Fe9  1  0.50078500  0.99905200  0.99890400  1.0
  Fe  Fe10  1  0.50000100  0.99972600  0.50004300  1.0
  Fe  Fe11  1  0.49993000  0.50039700  0.49997900  1.0
  O  O12  1  0.82088200  0.00328500  0.40821800  1.0
  O  O13  1  0.84427400  0.01586000  0.09211100  1.0
  O  O14  1  0.83704300  0.49874800  0.40488800  1.0
  O  O15  1  0.82693300  0.48914000  0.08968500  1.0
  O  O16  1  0.66487200  0.26146200  0.91141700  1.0
  O  O17  1  0.65567600  0.23477900  0.59061500  1.0
  O  O18  1  0.66783400  0.73983800  0.91247200  1.0
  O  O19  1  0.66839000  0.76161200  0.58752600  1.0
  O  O20  1  0.33072800  0.23868100  0.41280100  1.0
  O  O21  1  0.31957400  0.25771500  0.08488300  1.0
  O  O22  1  0.34445800  0.76563000  0.40911800  1.0
  O  O23  1  0.34976000  0.73641400  0.09027000  1.0
  O  O24  1  0.17922400  0.99602000  0.59191700  1.0
  O  O25  1  0.16280600  0.50210300  0.59519400  1.0
  O  O26  1  0.15744000  0.00919000  0.90721600  1.0
  O  O27  1  0.17319800  0.48859300  0.90981200  1.0

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