Li2FeCo3O8

High-Entropy Materials HEA

MP-ID: mp-775721 · Space group: R3m (#160)

Materials Project API

Basic Information

Formula

Li2FeCo3O8

MP-ID

mp-775721

Elements

Sites

Density

4.6975

g/cm³

Volume

132.39

Å³

Cell a

5.7352

Cell b

5.7352

Cell c

5.7352

α Angle

59.67

β Angle

59.67

γ Angle

59.67

Space Group

R3m

Point Group

Crystal System

Trigonal

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
18.90	4.6945	100.0	(1,1,1)
19.03	4.6632	6.0	(0,0,1)
19.03	4.6632	12.1	(1,0,0)
21.97	4.0452	46.8	(1,1,0)
31.19	2.8675	41.7	(2,1,1)
36.73	2.4471	20.8	(2,2,1)
36.86	2.4382	15.3	(1,0,2)
36.86	2.4382	30.6	(2,1,0)
36.93	2.4338	82.0	(1,1,-1)
38.35	2.3472	4.8	(2,2,2)
38.62	2.3316	3.4	(0,0,2)
38.62	2.3316	6.8	(2,0,0)
44.81	2.0226	56.1	(2,2,0)
48.88	1.8634	1.6	(3,2,2)
49.04	1.8575	2.2	(1,1,3)
49.04	1.8575	4.3	(3,1,1)
49.21	1.8517	1.2	(1,0,-2)
49.21	1.8517	2.4	(2,0,-1)
50.34	1.8127	3.0	(2,1,3)
50.34	1.8127	5.9	(3,2,1)
50.55	1.8055	6.0	(2,1,-1)
55.71	1.6501	4.2	(1,0,3)
55.71	1.6501	8.4	(3,1,0)
59.03	1.5648	3.6	(3,3,3)

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Energy Properties

Formation Energy/atom

-1.46722

eV/atom

Energy/atom

-6.70092

eV/atom

Energy above Hull

0.0962

eV/atom

Uncorrected Energy

-5.7962

eV/atom

Volume/atom

9.46

Å³

c/a Ratio

1.0000

Electronic Properties

Metallic

Metal

Band Gap

Direct Gap

CBM

N/A

Magnetic Properties

Magnetic

Yes

Total Mag. Moment

9.0057

μB

Mag. Ordering

Mag. Sites

Magnetization/Volume

0.068020

μB/Å³

Elastic Properties

Elastic data not available

Feature Analysis

Composition Overview

Element Composition (atomic fraction)

Composition Info

Major / Matrix Element

O · 0.571

Element Family

Metalloid-Nonmetal

Solute Fraction

0.429

Interstitial Fraction

0.000

High-Entropy Alloy Features

Composite Radar (normalized)

Element-Class Share

Mix Entropy ΔS/R

1.1164

HEA criterion (>1.0 = high entropy)

Mix Entropy ΔS

9.2815

J/mol·K

Ω Parameter

0.9573

Ω > 1.1 favors solid solution

Atomic Size Mismatch δr

40.987%

δr < 6.6% favors single-phase solid solution

Electronegativity Diff Δχ

0.9644

smaller = more stable mixing

VEC

4.929

valence electron concentration, affects phase stability

Mix Enthalpy ΔH_mix

-5.860

kJ/mol; negative = exothermic mixing

Entropy Norm

0.8053

SS Former

Phase Tendency

Related Tasks

Related computation task IDs (2)

aaabzjno aaadxvmb

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-775721

Reference Citation

The crystal structure and related material properties of Li2FeCo3O8 were obtained from the Materials Project database (MP-ID: mp-775721, 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_Li2FeCo3O8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.73522366
_cell_length_b   5.73522366
_cell_length_c   5.73522444
_cell_angle_alpha   59.66878925
_cell_angle_beta   59.66878925
_cell_angle_gamma   59.66879164
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Li2FeCo3O8
_chemical_formula_sum   'Li2 Fe1 Co3 O8'
_cell_volume   132.39018331
_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
  Li  Li0  1  0.12301500  0.12301500  0.12301500  1.0
  Li  Li1  1  0.49888300  0.49888300  0.49888300  1.0
  Fe  Fe2  1  0.88115400  0.88115400  0.88115400  1.0
  Co  Co3  1  0.01114900  0.49839500  0.49839500  1.0
  Co  Co4  1  0.49839500  0.01114900  0.49839500  1.0
  Co  Co5  1  0.49839500  0.49839500  0.01114900  1.0
  O  O6  1  0.26454900  0.26454900  0.26454900  1.0
  O  O7  1  0.24598800  0.24598800  0.71189100  1.0
  O  O8  1  0.24598800  0.71189100  0.24598800  1.0
  O  O9  1  0.71189100  0.24598800  0.24598800  1.0
  O  O10  1  0.28586100  0.74668300  0.74668300  1.0
  O  O11  1  0.74668300  0.28586100  0.74668300  1.0
  O  O12  1  0.74668300  0.74668300  0.28586100  1.0
  O  O13  1  0.74136700  0.74136700  0.74136700  1.0

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