KFeSe2

High-Entropy Materials HEA Traditional Materials TRA Elasticity Data ELA

MP-ID: mp-9884 · Space group: C2/c (#15)

Materials Project API

Basic Information

Formula

KFeSe2

MP-ID

mp-9884

Elements

Sites

Density

3.8870

g/cm³

Volume

216.05

Å³

Cell a

5.5498

Cell b

6.8120

Cell c

6.8120

α Angle

114.86

β Angle

101.83

γ Angle

101.83

Space Group

C2/c

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
15.17	5.8389	56.1	(0,0,1)
15.17	5.8389	56.1	(0,1,0)
15.44	5.7407	62.1	(0,1,-1)
18.91	4.6924	5.5	(1,0,-1)
18.91	4.6924	5.5	(1,-1,0)
23.25	3.8258	11.8	(1,1,-1)
23.25	3.8258	11.8	(1,-1,1)
26.28	3.3907	2.3	(0,1,1)
26.62	3.3482	100.0	(1,1,0)
26.75	3.3330	13.4	(0,1,-2)
26.75	3.3330	13.4	(0,2,-1)
29.09	3.0700	7.6	(1,1,-2)
29.09	3.0700	7.6	(1,-2,1)
29.84	2.9945	85.5	(1,0,-2)
29.84	2.9945	85.5	(1,-2,0)
30.62	2.9195	2.8	(0,0,2)
30.62	2.9195	2.8	(0,2,0)
31.16	2.8703	35.7	(0,2,-2)
33.22	2.6972	12.6	(2,0,-1)
33.22	2.6972	12.6	(2,-1,0)
34.73	2.5829	29.8	(1,2,-1)
34.73	2.5829	29.8	(1,-1,2)
34.90	2.5707	2.3	(2,-1,-1)
34.97	2.5657	5.4	(2,0,0)

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Energy Properties

Formation Energy/atom

-0.88490

eV/atom

Energy/atom

-5.03320

eV/atom

Energy above Hull

0.0005

eV/atom

Uncorrected Energy

-13.0633

eV/atom

Volume/atom

27.01

Å³

c/a Ratio

1.2274

Electronic Properties

Metallic

Metal

Band Gap

Direct Gap

CBM

N/A

Magnetic Properties

Magnetic

Yes

Total Mag. Moment

6.0104

μB

Mag. Ordering

Unknown

Mag. Sites

Magnetization/Volume

0.027820

μB/Å³

Elastic Properties

K_VRH

19.144

GPa

G_VRH

7.483

GPa

Young's Modulus E

19.861

GPa

Poisson Ratio ν

0.327

Pugh Ratio K/G

2.558

Vickers Hardness Est.

0.000

GPa

Ductility

Brittle

Anisotropy

1.458

Lame λ

14.155

GPa

Feature Analysis

Composition Overview

Element Composition (atomic fraction)

Composition Info

Major / Matrix Element

Se · 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

30.630%

δr < 6.6% favors single-phase solid solution

Electronegativity Diff Δχ

0.7090

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

0.428

Family

Se-rich Multi-Component

Matrix Element

Se · 0.500

Elasticity Features

Elastic Modulus Comparison (GPa)

Elastic Features

Elastic Anisotropy A^U

1.4580

Homogeneous Poisson ν

0.3270

Debye Temperature

255.2

Sound Velocity

1,555.2

m/s

Homogeneity

0.3270

Related Tasks

Related computation task IDs (5)

aaadndxf aaaemcgi aaaeubgr aaaeyvsu aaafcrvc

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-9884

Reference Citation

The crystal structure and related material properties of KFeSe2 were obtained from the Materials Project database (MP-ID: mp-9884, 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_KFeSe2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.54977449
_cell_length_b   6.81197849
_cell_length_c   6.81198381
_cell_angle_alpha   114.85916061
_cell_angle_beta   101.83311991
_cell_angle_gamma   101.83300438
_symmetry_Int_Tables_number   1
_chemical_formula_structural   KFeSe2
_chemical_formula_sum   'K2 Fe2 Se4'
_cell_volume   216.04911682
_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  0.25000000  0.36309222  0.63690678  1.0
  K  K1  1  0.75000000  0.63690973  0.36309027  1.0
  Fe  Fe2  1  0.24999900  0.99613126  0.00386874  1.0
  Fe  Fe3  1  0.75000100  0.00382811  0.99617189  1.0
  Se  Se4  1  0.89469475  0.68580293  0.91484610  1.0
  Se  Se5  1  0.60530725  0.08515890  0.31419807  1.0
  Se  Se6  1  0.10543728  0.31419824  0.08511539  1.0
  Se  Se7  1  0.39456072  0.91487861  0.68580176  1.0

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