KCoO2

High-Entropy Materials HEA Traditional Materials TRA

MP-ID: mp-764372 · Space group: C2/m (#12)

Materials Project API

Basic Information

Formula

KCoO2

MP-ID

mp-764372

Elements

Sites

Density

3.2926

g/cm³

Volume

262.31

Å³

Cell a

3.2417

Cell b

10.4133

Cell c

7.7823

α Angle

93.13

β Angle

90.00

γ Angle

90.00

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
13.85	6.3943	21.4	(0,1,-1)
14.60	6.0675	54.3	(0,1,1)
17.06	5.1989	78.5	(0,2,0)
22.89	3.8853	3.5	(0,0,2)
27.60	3.2317	2.1	(0,3,-1)
27.91	3.1972	68.1	(0,2,-2)
28.77	3.1029	100.0	(0,3,1)
28.85	3.0948	59.9	(1,-1,0)
28.85	3.0948	59.9	(1,1,0)
29.44	3.0337	17.5	(0,2,2)
29.86	2.9918	1.7	(1,0,-1)
29.86	2.9918	1.7	(1,0,1)
34.26	2.6170	23.1	(1,-2,1)
34.27	2.6170	23.1	(1,2,-1)
34.50	2.5994	2.5	(0,4,0)
34.91	2.5698	21.2	(1,-2,-1)
34.91	2.5698	21.2	(1,2,1)
35.25	2.5463	7.4	(0,1,-3)
36.19	2.4818	47.5	(0,1,3)
37.44	2.4018	5.8	(1,-1,-2)
37.45	2.4017	5.8	(1,1,2)
40.69	2.2172	18.6	(0,4,-2)
44.04	2.0562	23.6	(1,-3,2)
44.04	2.0561	23.6	(1,3,-2)

Get direct link

Energy Properties

Formation Energy/atom

-1.39519

eV/atom

Energy/atom

-5.93537

eV/atom

Energy above Hull

0.1090

eV/atom

Uncorrected Energy

-5.1824

eV/atom

Volume/atom

16.39

Å³

c/a Ratio

2.4007

Electronic Properties

Metallic

Metal

Band Gap

Direct Gap

CBM

N/A

Magnetic Properties

Magnetic

Yes

Total Mag. Moment

0.0000

μB

Mag. Ordering

AFM

Mag. Sites

Magnetization/Volume

0.000000

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

56.357%

δr < 6.6% favors single-phase solid solution

Electronegativity Diff Δχ

1.1102

smaller = more stable mixing

VEC

4.500

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

0.396

Family

O-rich Multi-Component

Matrix Element

O · 0.500

Related Tasks

Related computation task IDs (4)

aaacuysu aaadocda aaaduqwq aaafbabu

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-764372

Reference Citation

The crystal structure and related material properties of KCoO2 were obtained from the Materials Project database (MP-ID: mp-764372, 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…

Style: Ball & Stick | Drag to rotate · Scroll to zoom · Right-click to pan

Raw CIF Data

# generated using pymatgen
data_KCoO2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.24169220
_cell_length_b   10.41332732
_cell_length_c   7.78229911
_cell_angle_alpha   93.13332037
_cell_angle_beta   90.00029830
_cell_angle_gamma   90.00099931
_symmetry_Int_Tables_number   1
_chemical_formula_structural   KCoO2
_chemical_formula_sum   'K4 Co4 O8'
_cell_volume   262.31279880
_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
  K  K0  1  0.50000000  0.32240800  0.02308700  1.0
  K  K1  1  0.00000000  0.82239800  0.52306700  1.0
  K  K2  1  0.49999900  0.67759100  0.97692500  1.0
  K  K3  1  0.00000000  0.17760200  0.47691500  1.0
  Co  Co4  1  0.99999800  0.96761100  0.15540500  1.0
  Co  Co5  1  0.50000200  0.53238900  0.34459800  1.0
  Co  Co6  1  0.49999800  0.46761000  0.65541300  1.0
  Co  Co7  1  0.00000000  0.03238700  0.84458700  1.0
  O  O8  1  0.50001400  0.37156700  0.44312900  1.0
  O  O9  1  0.00001100  0.87156000  0.94311800  1.0
  O  O10  1  0.49998600  0.62843900  0.55688300  1.0
  O  O11  1  0.99999100  0.12843800  0.05687200  1.0
  O  O12  1  0.49999900  0.05419600  0.72373700  1.0
  O  O13  1  0.00000100  0.55419800  0.22374600  1.0
  O  O14  1  0.50000200  0.94580900  0.27625600  1.0
  O  O15  1  0.99999900  0.44579600  0.77626100  1.0

Get direct link