KFeO2

High-Entropy Materials HEA Traditional Materials TRA

MP-ID: mp-759749 · Space group: C2/m (#12)

Materials Project API

Basic Information

Formula

KFeO2

MP-ID

mp-759749

Elements

Sites

Density

3.2017

g/cm³

Volume

131.67

Å³

Cell a

6.5941

Cell b

6.5941

Cell c

8.2406

α Angle

53.23

β Angle

126.77

γ Angle

152.17

Space Group

C2/m

Point Group

2/m

Crystal System

Monoclinic

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
13.65	6.4871	13.4	(0,0,1)
14.12	6.2723	30.4	(1,-1,-1)
17.60	5.0386	84.2	(1,-1,0)
21.58	4.1179	5.7	(1,-1,-2)
27.50	3.2435	57.5	(0,0,2)
28.35	3.1484	5.7	(1,-1,1)
28.46	3.1362	20.8	(2,-2,-2)
29.05	3.0736	66.8	(2,-2,-1)
29.53	3.0250	100.0	(1,0,0)
30.20	2.9595	2.6	(1,0,-1)
33.54	2.6721	8.2	(1,-1,-3)
34.14	2.6259	37.7	(2,-2,-3)
34.97	2.5657	16.8	(0,1,-1)
34.97	2.5657	16.8	(1,0,1)
35.36	2.5382	31.6	(2,-1,-1)
35.64	2.5193	3.0	(2,-2,0)
37.06	2.4260	10.4	(2,-1,-2)
39.06	2.3060	1.2	(2,-1,0)
41.37	2.1827	21.8	(1,-1,2)
42.71	2.1169	6.2	(3,-3,-2)
43.27	2.0908	2.2	(3,-3,-3)
43.61	2.0756	52.2	(2,-1,-3)
44.58	2.0325	39.6	(1,0,2)
45.54	1.9921	7.2	(3,-2,-2)

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Energy Properties

Formation Energy/atom

-1.68208

eV/atom

Energy/atom

-6.55640

eV/atom

Energy above Hull

0.0498

eV/atom

Uncorrected Energy

-5.6489

eV/atom

Volume/atom

16.46

Å³

c/a Ratio

1.2497

Electronic Properties

Metallic

Metal

Band Gap

Direct Gap

CBM

N/A

Magnetic Properties

Magnetic

Yes

Total Mag. Moment

10.0000

μB

Mag. Ordering

Unknown

Mag. Sites

Magnetization/Volume

0.075940

μB/Å³

Elastic Properties

Elastic data not available

Feature Analysis

Composition Overview

Element Composition (atomic fraction)

Composition Info

Major / Matrix Element

O · 0.500

Element Family

Metalloid-Nonmetal

Solute Fraction

0.500

Interstitial Fraction

0.000

High-Entropy Alloy Features

Composite Radar (normalized)

Element-Class Share

Mix Entropy ΔS/R

1.0397

HEA criterion (>1.0 = high entropy)

Mix Entropy ΔS

8.6442

J/mol·K

Ω Parameter

0.0000

Ω > 1.1 favors solid solution

Atomic Size Mismatch δr

56.266%

δr < 6.6% favors single-phase solid solution

Electronegativity Diff Δχ

1.1162

smaller = more stable mixing

VEC

4.250

valence electron concentration, affects phase stability

Mix Enthalpy ΔH_mix

0.000

kJ/mol; negative = exothermic mixing

Entropy Norm

0.9464

SS Former

Phase Tendency

Traditional Material Features

ROM Blended-Feature Radar

Rating & Classification

Tier

Score

0.395

Family

O-rich Multi-Component

Matrix Element

O · 0.500

Related Tasks

Related computation task IDs (6)

aaacujkv aaadoejk aaadvslv aaaeijta aaaeqczk aaafbedm

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-759749

Reference Citation

The crystal structure and related material properties of KFeO2 were obtained from the Materials Project database (MP-ID: mp-759749, 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_KFeO2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.59408171
_cell_length_b   6.59408184
_cell_length_c   8.24057684
_cell_angle_alpha   53.23109678
_cell_angle_beta   126.76890370
_cell_angle_gamma   152.17222890
_symmetry_Int_Tables_number   1
_chemical_formula_structural   KFeO2
_chemical_formula_sum   'K2 Fe2 O4'
_cell_volume   131.67479339
_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
  K  K0  1  0.16768155  0.83231845  0.68648942  1.0
  K  K1  1  0.83231845  0.16768155  0.31351058  1.0
  Fe  Fe2  1  0.02361265  0.97638735  0.18213142  1.0
  Fe  Fe3  1  0.97638735  0.02361265  0.81786858  1.0
  O  O4  1  0.13081409  0.86918591  0.09637723  1.0
  O  O5  1  0.46322241  0.53677759  0.67566233  1.0
  O  O6  1  0.53677759  0.46322241  0.32433767  1.0
  O  O7  1  0.86918591  0.13081409  0.90362277  1.0

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