Ba2YTlCu2O7

High-Entropy Materials HEA

MP-ID: mp-654374 · Space group: P4/mmm (#123)

Materials Project API

Basic Information

Formula

Ba2YTlCu2O7

MP-ID

mp-654374

Elements

Sites

Density

6.9552

g/cm³

Volume

192.68

Å³

Cell a

3.8782

Cell b

3.8782

Cell c

12.8104

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

Yes

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
6.90	12.8104	8.2	(0,0,1)
13.83	6.4052	3.5	(0,0,2)
23.97	3.7119	10.1	(1,0,1)
26.87	3.3175	46.2	(1,0,2)
27.86	3.2026	5.0	(0,0,4)
31.15	2.8709	100.0	(1,0,3)
32.65	2.7423	72.1	(1,1,0)
33.42	2.6816	8.2	(1,1,1)
35.02	2.5621	20.3	(0,0,5)
36.38	2.4694	8.3	(1,0,4)
42.28	2.1377	2.6	(1,0,5)
42.33	2.1351	4.1	(0,0,6)
43.44	2.0830	15.9	(1,1,4)
46.85	1.9391	36.3	(2,0,0)
48.63	1.8721	19.6	(1,1,5)
48.68	1.8704	1.3	(1,0,6)
49.83	1.8301	1.1	(0,0,7)
53.30	1.7187	2.5	(2,1,1)
54.47	1.6847	10.3	(1,1,6)
54.84	1.6741	13.8	(2,1,2)
55.39	1.6588	3.6	(2,0,4)
55.52	1.6550	13.8	(1,0,7)
57.34	1.6069	36.2	(2,1,3)
57.56	1.6013	1.6	(0,0,8)

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Energy Properties

Formation Energy/atom

-2.21220

eV/atom

Energy/atom

-6.48548

eV/atom

Energy above Hull

0.0000

eV/atom

Uncorrected Energy

-6.1156

eV/atom

Volume/atom

14.82

Å³

c/a Ratio

3.3032

Electronic Properties

Metallic

Metal

Band Gap

Direct Gap

CBM

N/A

Magnetic Properties

Magnetic

Total Mag. Moment

0.2426

μB

Mag. Ordering

Mag. Sites

Magnetization/Volume

0.001260

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

3.5838

Ω > 1.1 favors solid solution

Atomic Size Mismatch δr

54.618%

δr < 6.6% favors single-phase solid solution

Electronegativity Diff Δχ

1.0562

smaller = more stable mixing

VEC

4.615

valence electron concentration, affects phase stability

Mix Enthalpy ΔH_mix

-1.739

kJ/mol; negative = exothermic mixing

Entropy Norm

0.8101

SS Former

Phase Tendency

Related Tasks

Related computation task IDs (5)

aaaddsmi aaadmwvm aaadssha aaaeubzz aaafcdjt

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-654374

Reference Citation

The crystal structure and related material properties of Ba2YTlCu2O7 were obtained from the Materials Project database (MP-ID: mp-654374, 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_Ba2YTlCu2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.87822800
_cell_length_b   3.87822800
_cell_length_c   12.81036100
_cell_angle_alpha   90.00000000
_cell_angle_beta   90.00000000
_cell_angle_gamma   90.00000000
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ba2YTlCu2O7
_chemical_formula_sum   'Ba2 Y1 Tl1 Cu2 O7'
_cell_volume   192.67618718
_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  0.20682600  1.0
  Ba  Ba1  1  0.50000000  0.50000000  0.79317400  1.0
  Y  Y2  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  0.37482500  1.0
  Cu  Cu5  1  0.00000000  0.00000000  0.62517500  1.0
  O  O6  1  0.00000000  0.00000000  0.16461500  1.0
  O  O7  1  0.00000000  0.50000000  0.38764400  1.0
  O  O8  1  0.50000000  0.00000000  0.38764400  1.0
  O  O9  1  0.50000000  0.00000000  0.61235600  1.0
  O  O10  1  0.50000000  0.50000000  0.00000000  1.0
  O  O11  1  0.00000000  0.50000000  0.61235600  1.0
  O  O12  1  0.00000000  0.00000000  0.83538500  1.0

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