Li4TiFe4(Co2O9)2

High-Entropy Materials HEA

MP-ID: mp-774870 · Space group: Pmc2_1 (#26)

Materials Project API

Basic Information

Formula

Li4TiFe4(Co2O9)2

MP-ID

mp-774870

Elements

Sites

Density

4.2745

g/cm³

Volume

639.23

Å³

Cell a

2.8941

Cell b

8.8168

Cell c

25.0515

α Angle

90.00

β Angle

90.00

γ Angle

90.00

Space Group

Pmc2_1

Point Group

mm2

Crystal System

Orthorhombic

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
7.06	12.5257	26.8	(0,0,2)
10.64	8.3167	14.8	(0,1,1)
12.28	7.2098	2.1	(0,1,2)
14.14	6.2629	5.6	(0,0,4)
14.61	6.0628	32.6	(0,1,3)
17.37	5.1058	100.0	(0,1,4)
20.14	4.4084	47.9	(0,2,0)
20.39	4.3561	44.8	(0,1,5)
20.46	4.3417	47.1	(0,2,1)
22.81	3.8985	8.3	(0,2,3)
23.58	3.7735	18.4	(0,1,6)
28.50	3.1314	8.1	(0,0,8)
30.29	2.9509	1.9	(0,1,8)
32.29	2.7723	3.4	(0,3,3)
33.36	2.6858	1.3	(1,1,2)
35.41	2.5350	58.7	(0,3,5)
35.66	2.5178	8.8	(1,1,4)
35.85	2.5052	32.1	(0,0,10)
37.16	2.4193	27.3	(1,2,0)
37.30	2.4106	78.1	(1,1,5)
37.32	2.4098	3.0	(0,1,10)
37.34	2.4081	16.0	(1,2,1)
37.42	2.4033	6.3	(0,3,6)
38.24	2.3536	5.2	(0,2,9)

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Energy Properties

Formation Energy/atom

-1.71182

eV/atom

Energy/atom

-7.09919

eV/atom

Energy above Hull

0.0971

eV/atom

Uncorrected Energy

-6.1978

eV/atom

Volume/atom

10.31

Å³

c/a Ratio

8.6561

Electronic Properties

Metallic

Metal

Band Gap

Direct Gap

CBM

N/A

Magnetic Properties

Magnetic

Yes

Total Mag. Moment

47.4325

μB

Mag. Ordering

Mag. Sites

Magnetization/Volume

0.074200

μB/Å³

Elastic Properties

Elastic data not available

Feature Analysis

Composition Overview

Element Composition (atomic fraction)

Composition Info

Major / Matrix Element

O · 0.581

Element Family

Metalloid-Nonmetal

Solute Fraction

0.419

Interstitial Fraction

0.000

High-Entropy Alloy Features

Composite Radar (normalized)

Element-Class Share

Mix Entropy ΔS/R

1.2191

HEA criterion (>1.0 = high entropy)

Mix Entropy ΔS

10.1354

J/mol·K

Ω Parameter

0.3397

Ω > 1.1 favors solid solution

Atomic Size Mismatch δr

41.525%

δr < 6.6% favors single-phase solid solution

Electronegativity Diff Δχ

0.9619

smaller = more stable mixing

VEC

4.774

valence electron concentration, affects phase stability

Mix Enthalpy ΔH_mix

-18.343

kJ/mol; negative = exothermic mixing

Entropy Norm

0.7575

SS Former

Phase Tendency

Related Tasks

Related computation task IDs (1)

aaaeeqlv

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-774870

Reference Citation

The crystal structure and related material properties of Li4TiFe4(Co2O9)2 were obtained from the Materials Project database (MP-ID: mp-774870, 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_Li4TiFe4(Co2O9)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   2.89410100
_cell_length_b   8.81679200
_cell_length_c   25.05148800
_cell_angle_alpha   90.00000000
_cell_angle_beta   90.00000000
_cell_angle_gamma   90.00000000
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Li4TiFe4(Co2O9)2
_chemical_formula_sum   'Li8 Ti2 Fe8 Co8 O36'
_cell_volume   639.23096676
_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
  Li  Li0  1  0.50000000  0.92452700  0.99633600  1.0
  Li  Li1  1  0.50000000  0.95070700  0.20352300  1.0
  Li  Li2  1  0.50000000  0.04929300  0.70352300  1.0
  Li  Li3  1  0.50000000  0.07547300  0.49633600  1.0
  Li  Li4  1  0.50000000  0.45420900  0.52773900  1.0
  Li  Li5  1  0.50000000  0.44273600  0.29555600  1.0
  Li  Li6  1  0.50000000  0.55726400  0.79555600  1.0
  Li  Li7  1  0.50000000  0.54579100  0.02773900  1.0
  Ti  Ti8  1  0.50000000  0.24716400  0.39654900  1.0
  Ti  Ti9  1  0.50000000  0.75283600  0.89654900  1.0
  Fe  Fe10  1  0.50000000  0.77024700  0.30153700  1.0
  Fe  Fe11  1  0.00000000  0.89891200  0.58826800  1.0
  Fe  Fe12  1  0.00000000  0.10108800  0.08826800  1.0
  Fe  Fe13  1  0.50000000  0.22975300  0.80153700  1.0
  Fe  Fe14  1  0.50000000  0.26591100  0.19484900  1.0
  Fe  Fe15  1  0.00000000  0.39271600  0.91219200  1.0
  Fe  Fe16  1  0.00000000  0.60728400  0.41219200  1.0
  Fe  Fe17  1  0.50000000  0.73408900  0.69484900  1.0
  Co  Co18  1  0.50000000  0.75202100  0.50056200  1.0
  Co  Co19  1  0.50000000  0.75364300  0.10682700  1.0
  Co  Co20  1  0.00000000  0.89886200  0.80561900  1.0
  Co  Co21  1  0.00000000  0.10113800  0.30561900  1.0
  Co  Co22  1  0.50000000  0.24635700  0.60682700  1.0
  Co  Co23  1  0.50000000  0.24797900  0.00056200  1.0
  Co  Co24  1  0.00000000  0.39353900  0.69043000  1.0
  Co  Co25  1  0.00000000  0.60646100  0.19043000  1.0
  O  O26  1  0.50000000  0.75371500  0.42725700  1.0
  O  O27  1  0.50000000  0.74982000  0.57511300  1.0
  O  O28  1  0.00000000  0.81446700  0.94084800  1.0
  O  O29  1  0.00000000  0.79594000  0.15670400  1.0
  O  O30  1  0.00000000  0.86576100  0.66612600  1.0
  O  O31  1  0.50000000  0.84388000  0.76183400  1.0
  O  O32  1  0.00000000  0.89374400  0.50587000  1.0
  O  O33  1  0.00000000  0.90832200  0.27463000  1.0
  O  O34  1  0.50000000  0.94932300  0.85129800  1.0
  O  O35  1  0.50000000  0.94905200  0.08319900  1.0
  O  O36  1  0.50000000  0.05094800  0.58319900  1.0
  O  O37  1  0.50000000  0.05067700  0.35129800  1.0
  O  O38  1  0.00000000  0.09167800  0.77463000  1.0
  O  O39  1  0.00000000  0.10625600  0.00587000  1.0
  O  O40  1  0.50000000  0.15612000  0.26183400  1.0
  O  O41  1  0.00000000  0.13423900  0.16612600  1.0
  O  O42  1  0.00000000  0.20406000  0.65670400  1.0
  O  O43  1  0.00000000  0.18553300  0.44084800  1.0
  O  O44  1  0.50000000  0.25018000  0.07511300  1.0
  O  O45  1  0.50000000  0.24628500  0.92725700  1.0
  O  O46  1  0.00000000  0.30240100  0.56217400  1.0
  O  O47  1  0.00000000  0.29237300  0.33910300  1.0
  O  O48  1  0.00000000  0.35100600  0.83362900  1.0
  O  O49  1  0.50000000  0.34697400  0.73597200  1.0
  O  O50  1  0.00000000  0.39354100  0.99616400  1.0
  O  O51  1  0.00000000  0.40787700  0.21524100  1.0
  O  O52  1  0.50000000  0.43191100  0.64301900  1.0
  O  O53  1  0.50000000  0.45295400  0.41175500  1.0
  O  O54  1  0.50000000  0.54704600  0.91175500  1.0
  O  O55  1  0.50000000  0.56808900  0.14301900  1.0
  O  O56  1  0.00000000  0.59212300  0.71524100  1.0
  O  O57  1  0.00000000  0.60645900  0.49616400  1.0
  O  O58  1  0.50000000  0.65302600  0.23597200  1.0
  O  O59  1  0.00000000  0.64899400  0.33362900  1.0
  O  O60  1  0.00000000  0.70762700  0.83910300  1.0
  O  O61  1  0.00000000  0.69759900  0.06217400  1.0

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