K(FeSe)2

High-Entropy Materials HEA Traditional Materials TRA

MP-ID: mp-1070735 · Space group: I4/mmm (#139)

Materials Project API

Basic Information

Formula

K(FeSe)2

MP-ID

mp-1070735

Elements

Sites

Density

4.8045

g/cm³

Volume

106.70

Å³

Cell a

7.9189

Cell b

7.9189

Cell c

7.9189

α Angle

152.36

β Angle

152.36

γ Angle

39.49

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
11.87	7.4532	79.6	(1,1,-1)
24.27	3.6673	17.4	(1,0,-1)
29.68	3.0102	100.0	(2,1,-2)
33.49	2.6754	7.2	(1,-1,0)
35.66	2.5181	29.3	(2,0,-1)
38.44	2.3417	10.3	(3,2,-3)
41.55	2.1733	59.3	(3,1,-2)
48.10	1.8918	37.8	(1,-1,1)
48.88	1.8633	12.7	(4,4,-4)
49.09	1.8558	10.4	(4,3,-4)
49.72	1.8336	8.3	(2,0,-2)
50.11	1.8205	40.7	(4,2,-3)
54.59	1.6813	4.1	(2,-1,-1)
57.54	1.6017	28.4	(3,0,-2)
61.07	1.5173	1.2	(5,4,-5)
62.29	1.4907	3.9	(5,5,-5)
63.19	1.4716	4.3	(4,1,-3)
70.38	1.3377	11.4	(2,-2,0)
71.00	1.3275	15.5	(5,3,-5)
71.17	1.3248	7.1	(5,2,-4)
71.68	1.3167	2.6	(3,-1,-1)
74.35	1.2758	7.2	(6,5,-6)
78.20	1.2224	5.7	(3,0,-3)
80.23	1.1965	1.3	(2,-2,1)

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Energy Properties

Formation Energy/atom

-0.67707

eV/atom

Energy/atom

-5.68971

eV/atom

Energy above Hull

0.0328

eV/atom

Uncorrected Energy

-5.5009

eV/atom

Volume/atom

21.34

Å³

c/a Ratio

1.0000

Electronic Properties

Metallic

Metal

Band Gap

Direct Gap

CBM

N/A

Magnetic Properties

Magnetic

Yes

Total Mag. Moment

6.0504

μB

Mag. Ordering

Mag. Sites

Magnetization/Volume

0.056710

μB/Å³

Elastic Properties

Elastic data not available

Feature Analysis

Composition Overview

Element Composition (atomic fraction)

Composition Info

Major / Matrix Element

Fe · 0.400

Element Family

3d-TM

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

28.563%

δr < 6.6% favors single-phase solid solution

Electronegativity Diff Δχ

0.6356

smaller = more stable mixing

VEC

5.000

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

0.531

Family

Fe-rich Multi-Component

Matrix Element

Fe · 0.400

Related Tasks

Related computation task IDs (5)

aaaciybu aaadcpxl aaadwfzu aaaesnbe aaafcijg

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-1070735

Reference Citation

The crystal structure and related material properties of K(FeSe)2 were obtained from the Materials Project database (MP-ID: mp-1070735, 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_K(FeSe)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.91886339
_cell_length_b   7.91886339
_cell_length_c   7.91886339
_cell_angle_alpha   152.35730514
_cell_angle_beta   152.35730514
_cell_angle_gamma   39.49174662
_symmetry_Int_Tables_number   1
_chemical_formula_structural   K(FeSe)2
_chemical_formula_sum   'K1 Fe2 Se2'
_cell_volume   106.69540665
_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  0.00000000  0.00000000  0.00000000  1.0
  Fe  Fe1  1  0.75000000  0.25000000  0.50000000  1.0
  Fe  Fe2  1  0.25000000  0.75000000  0.50000000  1.0
  Se  Se3  1  0.64118300  0.64118300  0.00000000  1.0
  Se  Se4  1  0.35881700  0.35881700  0.00000000  1.0

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