K2CuO2

High-Entropy Materials HEA Traditional Materials TRA

MP-ID: mp-1021659 · Space group: I4/mmm (#139)

Materials Project API

Basic Information

Formula

K2CuO2

MP-ID

mp-1021659

Elements

Sites

Density

3.2488

g/cm³

Volume

88.80

Å³

Cell a

5.7673

Cell b

5.7673

Cell c

5.7673

α Angle

136.79

β Angle

136.79

γ Angle

62.76

Space Group

I4/mmm

Point Group

4/mmm

Crystal System

Tetragonal

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
18.02	4.9239	3.9	(1,1,-1)
22.80	3.8996	100.0	(1,0,0)
29.75	3.0029	12.2	(0,0,1)
34.53	2.5972	34.3	(2,1,-1)
35.00	2.5638	94.0	(1,1,0)
36.50	2.4619	51.1	(2,2,-2)
42.58	2.1234	63.1	(1,-1,1)
46.58	1.9498	1.4	(2,0,0)
47.77	1.9039	4.1	(2,2,-1)
48.84	1.8649	24.6	(1,0,1)
51.12	1.7868	10.6	(3,2,-2)
55.93	1.6439	15.9	(2,1,0)
57.30	1.6080	46.5	(3,1,-1)
61.79	1.5015	17.9	(0,0,2)
64.73	1.4402	14.5	(3,3,-2)
66.76	1.4012	4.4	(2,-1,1)
68.65	1.3671	8.1	(3,2,-1)
70.52	1.3355	3.7	(4,3,-3)
72.75	1.2999	3.4	(3,0,0)
73.03	1.2956	20.0	(2,0,1)
73.94	1.2819	19.5	(2,2,0)
77.55	1.2310	4.2	(4,4,-4)
82.47	1.1695	4.7	(1,0,2)
84.24	1.1495	2.2	(4,1,-1)

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Energy Properties

Formation Energy/atom

-0.54167

eV/atom

Energy/atom

-3.79325

eV/atom

Energy above Hull

0.7917

eV/atom

Uncorrected Energy

-3.5185

eV/atom

Volume/atom

17.76

Å³

c/a Ratio

1.0000

Electronic Properties

Metallic

Metal

Band Gap

Direct Gap

CBM

N/A

Magnetic Properties

Magnetic

Total Mag. Moment

0.2979

μB

Mag. Ordering

Mag. Sites

Magnetization/Volume

0.003360

μB/Å³

Elastic Properties

Elastic data not available

Feature Analysis

Composition Overview

Element Composition (atomic fraction)

Composition Info

Major / Matrix Element

K · 0.400

Element Family

Alkali-AlkEarth

Solute Fraction

0.600

Interstitial Fraction

0.000

High-Entropy Alloy Features

Composite Radar (normalized)

Element-Class Share

Mix Entropy ΔS/R

1.0549

HEA criterion (>1.0 = high entropy)

Mix Entropy ΔS

8.7706

J/mol·K

Ω Parameter

0.0000

Ω > 1.1 favors solid solution

Atomic Size Mismatch δr

52.118%

δr < 6.6% favors single-phase solid solution

Electronegativity Diff Δχ

1.1753

smaller = more stable mixing

VEC

4.200

valence electron concentration, affects phase stability

Mix Enthalpy ΔH_mix

0.000

kJ/mol; negative = exothermic mixing

Entropy Norm

0.9602

SS Former

Phase Tendency

Traditional Material Features

ROM Blended-Feature Radar

Rating & Classification

Tier

Score

0.215

Family

K-rich Multi-Component

Matrix Element

K · 0.400

Related Tasks

Related computation task IDs (5)

aaadbaak aaadmfze aaadtkot aaaesmjw aaafxbae

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-1021659

Reference Citation

The crystal structure and related material properties of K2CuO2 were obtained from the Materials Project database (MP-ID: mp-1021659, 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_K2CuO2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.76733358
_cell_length_b   5.76733358
_cell_length_c   5.76733358
_cell_angle_alpha   136.79361239
_cell_angle_beta   136.79361239
_cell_angle_gamma   62.75575526
_symmetry_Int_Tables_number   1
_chemical_formula_structural   K2CuO2
_chemical_formula_sum   'K2 Cu1 O2'
_cell_volume   88.80322453
_cell_formula_units_Z   1
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  0.75000000  0.25000000  0.50000000  1.0
  K  K1  1  0.25000000  0.75000000  0.50000000  1.0
  Cu  Cu2  1  0.00000000  0.00000000  0.00000000  1.0
  O  O3  1  0.50000000  0.00000000  0.50000000  1.0
  O  O4  1  0.00000000  0.50000000  0.50000000  1.0

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