Ba2TlFe2O7

High-Entropy Materials HEA

MP-ID: mp-1046342 · Space group: P4/mmm (#123)

Materials Project API

Basic Information

Formula

Ba2TlFe2O7

MP-ID

mp-1046342

Elements

Sites

Density

6.1472

g/cm³

Volume

189.83

Å³

Cell a

3.7625

Cell b

3.7625

Cell c

13.4090

α Angle

90.00

β Angle

90.00

γ Angle

90.00

Space Group

P4/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
6.59	13.4090	83.0	(0,0,1)
19.86	4.4697	2.8	(0,0,3)
23.65	3.7625	2.1	(1,0,0)
26.59	3.3523	2.6	(0,0,4)
27.18	3.2812	100.0	(1,0,2)
31.07	2.8784	61.7	(1,0,3)
33.41	2.6818	33.4	(0,0,5)
33.69	2.6605	51.7	(1,1,0)
34.36	2.6096	20.6	(1,1,1)
35.88	2.5029	1.3	(1,0,4)
40.36	2.2348	2.0	(0,0,6)
43.42	2.0840	11.7	(1,1,4)
47.31	1.9214	1.9	(1,0,6)
48.18	1.8887	36.5	(1,1,5)
48.38	1.8813	27.2	(2,0,0)
48.89	1.8630	3.4	(2,0,1)
53.55	1.7112	2.7	(1,1,6)
53.69	1.7071	18.1	(1,0,7)
56.06	1.6406	1.9	(2,0,4)
56.38	1.6320	27.1	(2,1,2)
58.62	1.5748	21.3	(2,1,3)
60.07	1.5401	23.2	(2,0,5)
60.47	1.5311	10.1	(1,0,8)
64.78	1.4392	1.9	(2,0,6)

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Energy Properties

Formation Energy/atom

-1.71864

eV/atom

Energy/atom

-6.53407

eV/atom

Energy above Hull

0.2745

eV/atom

Uncorrected Energy

-5.7573

eV/atom

Volume/atom

15.82

Å³

c/a Ratio

3.5638

Electronic Properties

Metallic

Metal

Band Gap

Direct Gap

CBM

N/A

Magnetic Properties

Magnetic

Yes

Total Mag. Moment

8.6109

μB

Mag. Ordering

Mag. Sites

Magnetization/Volume

0.045360

μB/Å³

Elastic Properties

Elastic data not available

Feature Analysis

Composition Overview

Element Composition (atomic fraction)

Composition Info

Major / Matrix Element

O · 0.583

Element Family

Metalloid-Nonmetal

Solute Fraction

0.417

Interstitial Fraction

0.000

High-Entropy Alloy Features

Composite Radar (normalized)

Element-Class Share

Mix Entropy ΔS/R

1.1187

HEA criterion (>1.0 = high entropy)

Mix Entropy ΔS

9.3012

J/mol·K

Ω Parameter

3.5758

Ω > 1.1 favors solid solution

Atomic Size Mismatch δr

56.780%

δr < 6.6% favors single-phase solid solution

Electronegativity Diff Δχ

1.0382

smaller = more stable mixing

VEC

4.250

valence electron concentration, affects phase stability

Mix Enthalpy ΔH_mix

1.427

kJ/mol; negative = exothermic mixing

Entropy Norm

0.8070

SS Former

Phase Tendency

Related Tasks

Related computation task IDs (5)

aaachnwu aaadbexq aaadvech aaaeplug aaafaybv

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-1046342

Reference Citation

The crystal structure and related material properties of Ba2TlFe2O7 were obtained from the Materials Project database (MP-ID: mp-1046342, 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_Ba2TlFe2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.76252400
_cell_length_b   3.76252400
_cell_length_c   13.40898800
_cell_angle_alpha   90.00000000
_cell_angle_beta   90.00000000
_cell_angle_gamma   90.00000000
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ba2TlFe2O7
_chemical_formula_sum   'Ba2 Tl1 Fe2 O7'
_cell_volume   189.82550320
_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
  Ba  Ba0  1  0.50000000  0.50000000  0.70643900  1.0
  Ba  Ba1  1  0.50000000  0.50000000  0.29356100  1.0
  Tl  Tl2  1  0.00000000  0.00000000  0.50000000  1.0
  Fe  Fe3  1  0.00000000  0.00000000  0.89314200  1.0
  Fe  Fe4  1  0.00000000  0.00000000  0.10685800  1.0
  O  O5  1  0.50000000  0.50000000  0.50000000  1.0
  O  O6  1  0.00000000  0.50000000  0.86938500  1.0
  O  O7  1  0.50000000  0.00000000  0.86938500  1.0
  O  O8  1  0.00000000  0.50000000  0.13061500  1.0
  O  O9  1  0.50000000  0.00000000  0.13061500  1.0
  O  O10  1  0.00000000  0.00000000  0.65502900  1.0
  O  O11  1  0.00000000  0.00000000  0.34497100  1.0

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