Ba2AlTlCu2O7

High-Entropy Materials HEA

MP-ID: mp-1046001 · Space group: P4/mmm (#123)

Materials Project API

Basic Information

Formula

Ba2AlTlCu2O7

MP-ID

mp-1046001

Elements

Sites

Density

6.7954

g/cm³

Volume

182.08

Å³

Cell a

3.7526

Cell b

3.7526

Cell c

12.9296

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
6.84	12.9296	34.8	(0,0,1)
13.70	6.4648	1.1	(0,0,2)
20.61	4.3099	1.9	(0,0,3)
23.71	3.7526	1.9	(1,0,0)
24.70	3.6039	3.1	(1,0,1)
27.48	3.2455	100.0	(1,0,2)
27.60	3.2324	6.0	(0,0,4)
31.61	2.8302	81.8	(1,0,3)
33.78	2.6535	72.0	(1,1,0)
34.51	2.5993	17.2	(1,1,1)
34.69	2.5859	36.4	(0,0,5)
36.69	2.4491	7.0	(1,0,4)
42.45	2.1293	2.4	(1,0,5)
44.16	2.0510	15.7	(1,1,4)
48.52	1.8763	36.8	(2,0,0)
48.73	1.8687	4.4	(1,0,6)
49.06	1.8569	1.8	(2,0,1)
49.20	1.8520	34.2	(1,1,5)
54.88	1.6728	4.9	(1,1,6)
55.45	1.6572	18.8	(1,0,7)
56.67	1.6244	27.9	(2,1,2)
56.73	1.6227	3.9	(2,0,4)
56.98	1.6162	1.6	(0,0,8)
59.07	1.5639	28.7	(2,1,3)

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Energy Properties

Formation Energy/atom

-1.87233

eV/atom

Energy/atom

-5.93303

eV/atom

Energy above Hull

0.2772

eV/atom

Uncorrected Energy

-5.5631

eV/atom

Volume/atom

14.01

Å³

c/a Ratio

3.4455

Electronic Properties

Metallic

Metal

Band Gap

Direct Gap

CBM

N/A

Magnetic Properties

Magnetic

Total Mag. Moment

0.0024

μB

Mag. Ordering

Mag. Sites

Magnetization/Volume

0.000010

μB/Å³

Elastic Properties

Elastic data not available

Feature Analysis

Composition Overview

Element Composition (atomic fraction)

Composition Info

Major / Matrix Element

O · 0.538

Element Family

Metalloid-Nonmetal

Solute Fraction

0.462

Interstitial Fraction

0.000

High-Entropy Alloy Features

Composite Radar (normalized)

Element-Class Share

Mix Entropy ΔS/R

1.3039

HEA criterion (>1.0 = high entropy)

Mix Entropy ΔS

10.8404

J/mol·K

Ω Parameter

13.4851

Ω > 1.1 favors solid solution

Atomic Size Mismatch δr

53.828%

δr < 6.6% favors single-phase solid solution

Electronegativity Diff Δχ

1.0245

smaller = more stable mixing

VEC

4.615

valence electron concentration, affects phase stability

Mix Enthalpy ΔH_mix

-0.409

kJ/mol; negative = exothermic mixing

Entropy Norm

0.8101

SS Former

Phase Tendency

Related Tasks

Related computation task IDs (3)

aaachnjk aaadavuh aaadvepp

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-1046001

Reference Citation

The crystal structure and related material properties of Ba2AlTlCu2O7 were obtained from the Materials Project database (MP-ID: mp-1046001, 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_Ba2AlTlCu2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.75261800
_cell_length_b   3.75261800
_cell_length_c   12.92960200
_cell_angle_alpha   90.00000000
_cell_angle_beta   90.00000000
_cell_angle_gamma   90.00000000
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ba2AlTlCu2O7
_chemical_formula_sum   'Ba2 Al1 Tl1 Cu2 O7'
_cell_volume   182.07648948
_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  0.21261400  1.0
  Ba  Ba1  1  0.50000000  0.50000000  0.78738600  1.0
  Al  Al2  1  0.50000000  0.50000000  0.50000000  1.0
  Tl  Tl3  1  0.00000000  0.00000000  0.00000000  1.0
  Cu  Cu4  1  0.00000000  0.00000000  0.38553800  1.0
  Cu  Cu5  1  0.00000000  0.00000000  0.61446200  1.0
  O  O6  1  0.00000000  0.00000000  0.16412300  1.0
  O  O7  1  0.00000000  0.50000000  0.40368600  1.0
  O  O8  1  0.50000000  0.00000000  0.40368600  1.0
  O  O9  1  0.50000000  0.00000000  0.59631400  1.0
  O  O10  1  0.50000000  0.50000000  0.00000000  1.0
  O  O11  1  0.00000000  0.50000000  0.59631400  1.0
  O  O12  1  0.00000000  0.00000000  0.83587700  1.0

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