Basic Information
Formula
K2CoSe2
MP-ID
mp-8768
Elements
3
Sites
10
Density
3.3646
g/cm³
Volume
291.24
ų
Cell a
8.1337
Å
Cell b
8.1337
Å
Cell c
8.1337
Å
α Angle
134.93
°
β Angle
128.73
°
γ Angle
70.62
°
Space Group
Ibam
Point Group
mmm
Crystal System
Orthorhombic
Bravais Lattice
oI
Stability
No
Packing Fraction
-
X-ray Diffraction
Diffraction Pattern
X-axis: 2θ (°); Y-axis: relative intensity; Cu Kα ; λ=1.5418 Å
Diffraction Peaks (Top 24)
| 2θ | d (Å) | I | hkl |
|---|---|---|---|
| 13.34 | 6.6376 | 56.9 | (1,1,-1) |
| 14.24 | 6.2178 | 100.0 | (1,0,0) |
| 23.30 | 3.8176 | 35.9 | (1,1,0) |
| 23.75 | 3.7461 | 22.1 | (2,1,-1) |
| 25.31 | 3.5187 | 13.7 | (1,-1,1) |
| 26.86 | 3.3188 | 28.3 | (2,2,-2) |
| 28.64 | 3.1174 | 37.5 | (1,-1,-1) |
| 28.72 | 3.1089 | 4.1 | (2,0,0) |
| 29.93 | 2.9859 | 63.0 | (1,0,1) |
| 31.71 | 2.8217 | 2.3 | (0,2,0) |
| 32.12 | 2.7868 | 4.1 | (0,1,1) |
| 33.12 | 2.7046 | 41.4 | (2,2,-1) |
| 35.64 | 2.5193 | 48.8 | (2,1,0) |
| 37.24 | 2.4143 | 42.0 | (3,1,-1) |
| 37.53 | 2.3962 | 5.5 | (1,2,0) |
| 38.58 | 2.3334 | 47.6 | (0,0,2) |
| 39.67 | 2.2722 | 66.7 | (1,3,-1) |
| 41.00 | 2.2013 | 11.8 | (1,1,1) |
| 43.41 | 2.0845 | 2.5 | (2,0,1) |
| 43.67 | 2.0726 | 1.2 | (3,0,0) |
| 45.19 | 2.0066 | 6.2 | (3,2,-1) |
| 45.36 | 1.9992 | 2.1 | (3,3,-2) |
| 46.76 | 1.9428 | 16.6 | (2,3,-1) |
| 47.64 | 1.9090 | 6.0 | (0,2,1) |
Energy Properties
Formation Energy/atom
-0.90686
eV/atom
Energy/atom
-4.18446
eV/atom
Energy above Hull
0.0409
eV/atom
Uncorrected Energy
-3.9957
eV/atom
Volume/atom
29.12
ų
c/a Ratio
1.0000
Electronic Properties
Metallic
Metal
Band Gap
0
eV
Direct Gap
No
CBM
N/A
eV
Magnetic Properties
Magnetic
Yes
Total Mag. Moment
5.9994
μB
Mag. Ordering
FM
Mag. Sites
2
Magnetization/Volume
0.020600
μB/ų
Elastic Properties
Elastic data not available
Feature Analysis
Element Composition (atomic fraction)
Composition Info
Major / Matrix Element
K · 0.400
Element Family
Alkali-AlkEarth
Solute Fraction
0.600
Interstitial Fraction
0.000
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
31.409%
δr < 6.6% favors single-phase solid solution
Electronegativity Diff Δχ
0.7776
smaller = more stable mixing
VEC
3.800
valence electron concentration, affects phase stability
Mix Enthalpy ΔH_mix
0.000
kJ/mol; negative = exothermic mixing
Entropy Norm
0.9602
SS Former
0
Phase Tendency
IM
Related Tasks
Citation & References
Materials Project Page
https://materialsproject.org/materials/mp-8768
Reference Citation
The crystal structure and related material properties of K2CoSe2 were obtained from the Materials Project database (MP-ID: mp-8768, 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_K2CoSe2
_symmetry_space_group_name_H-M 'P 1'
_cell_length_a 8.13370581
_cell_length_b 8.13370581
_cell_length_c 8.13370581
_cell_angle_alpha 134.92734995
_cell_angle_beta 128.73360274
_cell_angle_gamma 70.61526221
_symmetry_Int_Tables_number 1
_chemical_formula_structural K2CoSe2
_chemical_formula_sum 'K4 Co2 Se4'
_cell_volume 291.23686869
_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 0.81678800 0.14415700 0.67263200 1.0
K K1 1 0.18321200 0.85584300 0.32736800 1.0
K K2 1 0.52847500 0.35584300 0.17263200 1.0
K K3 1 0.47152500 0.64415700 0.82736800 1.0
Co Co4 1 0.00000000 0.75000000 0.75000000 1.0
Co Co5 1 0.00000000 0.25000000 0.25000000 1.0
Se Se6 1 0.71420400 0.89849500 0.81570900 1.0
Se Se7 1 0.28579600 0.10150500 0.18429100 1.0
Se Se8 1 0.91721500 0.60150500 0.31570900 1.0
Se Se9 1 0.08278500 0.39849500 0.68429100 1.0
