KCuF3

High-Entropy Materials HEA Traditional Materials TRA Elasticity Data ELA

MP-ID: mp-669347 · Space group: I4/mcm (#140)

Materials Project API

Basic Information

Formula

KCuF3

MP-ID

mp-669347

Elements

Sites

Density

4.0089

g/cm³

Volume

132.25

Å³

Cell a

5.6801

Cell b

5.6807

Cell c

5.6807

α Angle

92.48

β Angle

118.58

γ Angle

118.58

Space Group

I4/mcm

Point Group

4/mmm

Crystal System

Tetragonal

Bravais Lattice

Stability

Yes

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
21.66	4.1030	34.3	(0,1,-1)
21.66	4.1021	34.3	(1,0,0)
22.63	3.9288	30.0	(1,-1,-1)
30.82	2.9009	100.0	(1,1,-1)
31.53	2.8377	46.3	(1,0,-2)
31.53	2.8377	46.3	(1,-2,0)
31.53	2.8374	46.3	(0,1,1)
31.53	2.8374	46.3	(2,-1,-1)
36.46	2.4640	1.2	(1,1,-2)
38.58	2.3337	2.4	(0,0,2)
38.58	2.3337	7.3	(0,2,0)
44.15	2.0515	56.7	(0,2,-2)
44.16	2.0511	56.7	(2,0,0)
46.21	1.9644	50.3	(2,-2,-2)
49.69	1.8348	3.3	(1,-2,2)
49.69	1.8348	3.3	(1,2,-2)
49.70	1.8346	3.3	(2,-1,1)
49.70	1.8346	3.3	(2,1,-1)
50.17	1.8185	6.2	(1,1,-3)
50.18	1.8182	3.1	(1,1,1)
50.18	1.8182	3.1	(3,-1,-1)
51.58	1.7718	3.2	(2,-1,-3)
51.58	1.7718	3.2	(2,-3,-1)
51.59	1.7717	3.2	(1,-2,-2)

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Energy Properties

Formation Energy/atom

-2.35601

eV/atom

Energy/atom

-4.55088

eV/atom

Energy above Hull

0.0000

eV/atom

Uncorrected Energy

-7.6234

eV/atom

Volume/atom

13.23

Å³

c/a Ratio

1.0001

Electronic Properties

Metallic

Metal

Band Gap

Direct Gap

CBM

N/A

Magnetic Properties

Magnetic

Yes

Total Mag. Moment

0.0003

μB

Mag. Ordering

Unknown

Mag. Sites

Magnetization/Volume

0.000000

μB/Å³

Elastic Properties

K_VRH

78.848

GPa

G_VRH

33.832

GPa

Young's Modulus E

88.796

GPa

Poisson Ratio ν

0.312

Pugh Ratio K/G

2.331

Vickers Hardness Est.

2.831

GPa

Ductility

Brittle

Anisotropy

3.061

Lame λ

56.293

GPa

Feature Analysis

Composition Overview

Element Composition (atomic fraction)

Composition Info

Major / Matrix Element

F · 0.600

Element Family

Metalloid-Nonmetal

Solute Fraction

0.400

Interstitial Fraction

0.000

High-Entropy Alloy Features

Composite Radar (normalized)

Element-Class Share

Mix Entropy ΔS/R

0.9503

HEA criterion (>1.0 = high entropy)

Mix Entropy ΔS

7.9005

J/mol·K

Ω Parameter

0.0000

Ω > 1.1 favors solid solution

Atomic Size Mismatch δr

67.625%

δr < 6.6% favors single-phase solid solution

Electronegativity Diff Δχ

1.3282

smaller = more stable mixing

VEC

5.400

valence electron concentration, affects phase stability

Mix Enthalpy ΔH_mix

0.000

kJ/mol; negative = exothermic mixing

Entropy Norm

0.8650

SS Former

Phase Tendency

Traditional Material Features

ROM Blended-Feature Radar

Rating & Classification

Tier

Score

0.534

Family

F-rich Multi-Component

Matrix Element

F · 0.600

Elasticity Features

Elastic Modulus Comparison (GPa)

Elastic Features

Elastic Anisotropy A^U

3.0610

Homogeneous Poisson ν

0.3120

Debye Temperature

556.1

Sound Velocity

3,250.0

m/s

Homogeneity

0.3120

Related Tasks

Related computation task IDs (5)

aaadnaou aaadslun aaaekvmv aaaetyhg aaafwypl

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-669347

Reference Citation

The crystal structure and related material properties of KCuF3 were obtained from the Materials Project database (MP-ID: mp-669347, 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_KCuF3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.68005515
_cell_length_b   5.68067971
_cell_length_c   5.68068068
_cell_angle_alpha   92.48404255
_cell_angle_beta   118.57977552
_cell_angle_gamma   118.57977739
_symmetry_Int_Tables_number   1
_chemical_formula_structural   KCuF3
_chemical_formula_sum   'K2 Cu2 F6'
_cell_volume   132.25113411
_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  0.00000000  0.75000000  0.75000000  1.0
  K  K1  1  0.00000000  0.25000000  0.25000000  1.0
  Cu  Cu2  1  0.50000000  0.00000000  0.50000000  1.0
  Cu  Cu3  1  0.50000000  0.50000000  0.00000000  1.0
  F  F4  1  0.04217423  0.27108712  0.77108712  1.0
  F  F5  1  0.50000000  0.77115694  0.72884306  1.0
  F  F6  1  0.50000000  0.22884306  0.27115694  1.0
  F  F7  1  0.95782577  0.72891288  0.22891288  1.0
  F  F8  1  0.50000000  0.74995346  0.24995346  1.0
  F  F9  1  0.50000000  0.25004654  0.75004654  1.0

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