Ba2CaTlCu2O7
High-Entropy Materials HEAMP-ID: mp-632802 · Space group: P4/mmm (#123)
Basic Information
Formula
Ba2CaTlCu2O7
MP-ID
mp-632802
Elements
5
Sites
13
Density
6.5417
g/cm³
Volume
192.46
ų
Cell a
3.8405
Å
Cell b
3.8405
Å
Cell c
13.0488
Å
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
tP
Stability
No
Packing Fraction
-
X-ray Diffraction
Diffraction Pattern
X-axis: 2θ (°); Y-axis: relative intensity; Cu Kα ; λ=1.5418 Å
Diffraction Peaks (Top 24)
| 2θ | d (Å) | I | hkl |
|---|---|---|---|
| 6.77 | 13.0488 | 37.4 | (0,0,1) |
| 20.42 | 4.3496 | 3.3 | (0,0,3) |
| 23.16 | 3.8405 | 1.0 | (1,0,0) |
| 24.16 | 3.6842 | 5.0 | (1,0,1) |
| 26.94 | 3.3097 | 69.5 | (1,0,2) |
| 27.34 | 3.2622 | 3.7 | (0,0,4) |
| 31.06 | 2.8789 | 100.0 | (1,0,3) |
| 32.98 | 2.7157 | 70.7 | (1,1,0) |
| 33.71 | 2.6587 | 15.7 | (1,1,1) |
| 34.36 | 2.6098 | 26.1 | (0,0,5) |
| 36.13 | 2.4863 | 6.1 | (1,0,4) |
| 41.52 | 2.1748 | 4.7 | (0,0,6) |
| 43.35 | 2.0871 | 14.5 | (1,1,4) |
| 47.34 | 1.9203 | 36.2 | (2,0,0) |
| 47.88 | 1.8998 | 1.9 | (2,0,1) |
| 48.08 | 1.8924 | 5.3 | (1,0,6) |
| 48.37 | 1.8817 | 26.4 | (1,1,5) |
| 48.86 | 1.8641 | 1.3 | (0,0,7) |
| 52.06 | 1.7567 | 1.1 | (2,0,3) |
| 53.84 | 1.7028 | 1.2 | (2,1,1) |
| 54.02 | 1.6975 | 9.5 | (1,1,6) |
| 54.74 | 1.6770 | 12.3 | (1,0,7) |
| 55.31 | 1.6609 | 20.3 | (2,1,2) |
| 55.53 | 1.6548 | 2.6 | (2,0,4) |
Energy Properties
Formation Energy/atom
-1.97809
eV/atom
Energy/atom
-5.90495
eV/atom
Energy above Hull
0.0444
eV/atom
Uncorrected Energy
-5.5350
eV/atom
Volume/atom
14.80
ų
c/a Ratio
3.3977
Electronic Properties
Metallic
Metal
Band Gap
0
eV
Direct Gap
No
CBM
N/A
eV
Magnetic Properties
Magnetic
No
Total Mag. Moment
0.0283
μB
Mag. Ordering
NM
Mag. Sites
0
Magnetization/Volume
0.000150
μB/ų
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
3.4081
Ω > 1.1 favors solid solution
Atomic Size Mismatch δr
55.400%
δr < 6.6% favors single-phase solid solution
Electronegativity Diff Δχ
1.0781
smaller = more stable mixing
VEC
4.538
valence electron concentration, affects phase stability
Mix Enthalpy ΔH_mix
-1.662
kJ/mol; negative = exothermic mixing
Entropy Norm
0.8101
SS Former
0
Phase Tendency
IM
Related Tasks
Citation & References
Materials Project Page
https://materialsproject.org/materials/mp-632802
Reference Citation
The crystal structure and related material properties of Ba2CaTlCu2O7 were obtained from the Materials Project database (MP-ID: mp-632802, 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_Ba2CaTlCu2O7
_symmetry_space_group_name_H-M 'P 1'
_cell_length_a 3.84050200
_cell_length_b 3.84050200
_cell_length_c 13.04874800
_cell_angle_alpha 90.00000000
_cell_angle_beta 90.00000000
_cell_angle_gamma 90.00000000
_symmetry_Int_Tables_number 1
_chemical_formula_structural Ba2CaTlCu2O7
_chemical_formula_sum 'Ba2 Ca1 Tl1 Cu2 O7'
_cell_volume 192.46192942
_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 0.00000000 0.00000000 0.70809700 1.0
Ba Ba1 1 0.00000000 0.00000000 0.29190300 1.0
Ca Ca2 1 0.00000000 0.00000000 0.00000000 1.0
Tl Tl3 1 0.50000000 0.50000000 0.50000000 1.0
Cu Cu4 1 0.50000000 0.50000000 0.86837900 1.0
Cu Cu5 1 0.50000000 0.50000000 0.13162100 1.0
O O6 1 0.50000000 0.00000000 0.87997300 1.0
O O7 1 0.00000000 0.50000000 0.87997300 1.0
O O8 1 0.50000000 0.00000000 0.12002700 1.0
O O9 1 0.00000000 0.50000000 0.12002700 1.0
O O10 1 0.50000000 0.50000000 0.66006000 1.0
O O11 1 0.50000000 0.50000000 0.33994000 1.0
O O12 1 0.00000000 0.00000000 0.50000000 1.0
