Cs2KPbF6

High-Entropy Materials HEA Elasticity Data ELA

MP-ID: mp-989585 · Space group: Fm-3m (#225)

Materials Project API

Basic Information

Formula

Cs2KPbF6

MP-ID

mp-989585

Elements

Sites

Density

4.5187

g/cm³

Volume

230.08

Å³

Cell a

6.8781

Cell b

6.8781

Cell c

6.8781

α Angle

60.00

β Angle

60.00

γ Angle

60.00

Space Group

Fm-3m

Point Group

m-3m

Crystal System

Cubic

Bravais Lattice

Stability

Yes

Packing Fraction

0.7405

X-ray Diffraction

Diffraction Pattern

Target / Radiation

X-axis: 2θ (°); Y-axis: relative intensity; Cu Kα ; λ=1.5418 Å

Diffraction Peaks (Top 19)

2θ	d (Å)	I	hkl
15.78	5.6159	28.5	(1,1,1)
25.91	3.4390	100.0	(2,1,1)
30.48	2.9328	15.3	(2,2,1)
31.87	2.8080	3.2	(2,2,2)
36.97	2.4318	34.8	(2,2,0)
40.42	2.2315	6.1	(3,2,2)
45.69	1.9855	43.0	(3,3,2)
48.64	1.8720	7.3	(3,3,3)
53.27	1.7195	22.9	(4,2,2)
55.92	1.6442	7.2	(4,3,2)
60.17	1.5380	20.0	(4,3,1)
62.63	1.4834	2.2	(4,4,3)
66.61	1.4040	7.5	(4,4,4)
68.94	1.3621	4.0	(5,3,3)
72.75	1.2998	23.0	(5,4,3)
75.00	1.2664	3.9	(5,4,4)
78.70	1.2159	3.4	(4,4,0)
84.52	1.1463	11.7	(6,3,3)
86.69	1.1232	2.6	(6,4,3)

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Energy Properties

Formation Energy/atom

-2.77371

eV/atom

Energy/atom

-4.58846

eV/atom

Energy above Hull

0.0000

eV/atom

Uncorrected Energy

-4.3113

eV/atom

Volume/atom

23.01

Å³

c/a Ratio

1.0000

Electronic Properties

Metallic

Metal

Band Gap

Direct Gap

CBM

N/A

Magnetic Properties

Magnetic

Yes

Total Mag. Moment

0.9774

μB

Mag. Ordering

Mag. Sites

Magnetization/Volume

0.004250

μB/Å³

Elastic Properties

K_VRH

26.386

GPa

G_VRH

13.579

GPa

Young's Modulus E

34.772

GPa

Poisson Ratio ν

0.280

Pugh Ratio K/G

1.943

Vickers Hardness Est.

1.229

GPa

Ductility

Brittle

Anisotropy

0.814

Lame λ

17.333

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

1.0889

HEA criterion (>1.0 = high entropy)

Mix Entropy ΔS

9.0531

J/mol·K

Ω Parameter

0.0000

Ω > 1.1 favors solid solution

Atomic Size Mismatch δr

74.349%

δr < 6.6% favors single-phase solid solution

Electronegativity Diff Δχ

1.4331

smaller = more stable mixing

VEC

3.700

valence electron concentration, affects phase stability

Mix Enthalpy ΔH_mix

0.000

kJ/mol; negative = exothermic mixing

Entropy Norm

0.7855

SS Former

Phase Tendency

Elasticity Features

Elastic Modulus Comparison (GPa)

Elastic Features

Elastic Anisotropy A^U

0.8140

Homogeneous Poisson ν

0.2800

Debye Temperature

292.2

Sound Velocity

1,931.6

m/s

Homogeneity

0.2800

Related Tasks

Related computation task IDs (5)

aaadasni aaadqdwu aaadvdlq aaaeplwt aaafayjj

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-989585

Reference Citation

The crystal structure and related material properties of Cs2KPbF6 were obtained from the Materials Project database (MP-ID: mp-989585, 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_Cs2KPbF6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.87805453
_cell_length_b   6.87805453
_cell_length_c   6.87805453
_cell_angle_alpha   60.00000000
_cell_angle_beta   60.00000000
_cell_angle_gamma   60.00000000
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Cs2KPbF6
_chemical_formula_sum   'Cs2 K1 Pb1 F6'
_cell_volume   230.08157742
_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
  Cs  Cs0  1  0.25000000  0.25000000  0.25000000  1.0
  Cs  Cs1  1  0.75000000  0.75000000  0.75000000  1.0
  K  K2  1  0.50000000  0.50000000  0.50000000  1.0
  Pb  Pb3  1  0.00000000  0.00000000  0.00000000  1.0
  F  F4  1  0.23349800  0.76650200  0.76650200  1.0
  F  F5  1  0.23349800  0.76650200  0.23349800  1.0
  F  F6  1  0.76650200  0.23349800  0.76650200  1.0
  F  F7  1  0.76650200  0.76650200  0.23349800  1.0
  F  F8  1  0.23349800  0.23349800  0.76650200  1.0
  F  F9  1  0.76650200  0.23349800  0.23349800  1.0

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