Ba2Er(CuO2)4

High-Entropy Materials HEA

MP-ID: mp-6583 · Space group: Cmmm (#65)

Materials Project API

Basic Information

Formula

Ba2Er(CuO2)4

MP-ID

mp-6583

Elements

Sites

Density

6.6116

g/cm³

Volume

206.97

Å³

Cell a

13.8691

Cell b

13.8691

Cell c

3.8735

α Angle

90.00

β Angle

90.00

γ Angle

163.87

Space Group

Cmmm

Point Group

mmm

Crystal System

Orthorhombic

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
6.44	13.7320	72.9	(1,-1,0)
19.39	4.5773	8.6	(3,-3,0)
22.96	3.8735	1.8	(0,0,1)
23.09	3.8527	15.6	(1,0,0)
23.87	3.7280	21.4	(1,-1,1)
25.95	3.4330	6.5	(4,-4,0)
26.42	3.3736	12.9	(2,-2,1)
30.23	2.9568	41.4	(3,-3,1)
32.41	2.7628	94.7	(4,-3,0)
32.60	2.7464	1.1	(5,-5,0)
32.79	2.7316	100.0	(1,0,1)
34.10	2.6295	8.3	(2,-1,1)
34.92	2.5692	64.6	(4,-4,1)
36.59	2.4556	3.8	(3,-2,1)
37.45	2.4012	13.0	(5,-4,0)
39.37	2.2887	4.5	(6,-6,0)
40.09	2.2493	18.7	(4,-3,1)
44.39	2.0409	10.4	(5,-4,1)
46.06	1.9704	2.3	(6,-6,1)
46.28	1.9617	18.9	(7,-7,0)
46.69	1.9456	31.0	(1,1,0)
46.91	1.9367	30.5	(0,0,2)
47.18	1.9264	1.3	(2,0,0)
47.41	1.9178	1.3	(1,-1,2)

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Energy Properties

Formation Energy/atom

-2.06368

eV/atom

Energy/atom

-6.35610

eV/atom

Energy above Hull

0.0000

eV/atom

Uncorrected Energy

-5.9897

eV/atom

Volume/atom

13.80

Å³

c/a Ratio

0.2793

Electronic Properties

Metallic

Metal

Band Gap

Direct Gap

CBM

N/A

Magnetic Properties

Magnetic

Total Mag. Moment

0.0487

μB

Mag. Ordering

Mag. Sites

Magnetization/Volume

0.000240

μB/Å³

Elastic Properties

Elastic data not available

Feature Analysis

Composition Overview

Element Composition (atomic fraction)

Composition Info

Major / Matrix Element

O · 0.533

Element Family

Metalloid-Nonmetal

Solute Fraction

0.467

Interstitial Fraction

0.000

High-Entropy Alloy Features

Composite Radar (normalized)

Element-Class Share

Mix Entropy ΔS/R

1.1369

HEA criterion (>1.0 = high entropy)

Mix Entropy ΔS

9.4523

J/mol·K

Ω Parameter

0.0000

Ω > 1.1 favors solid solution

Atomic Size Mismatch δr

52.790%

δr < 6.6% favors single-phase solid solution

Electronegativity Diff Δχ

1.0084

smaller = more stable mixing

VEC

6.133

valence electron concentration, affects phase stability

Mix Enthalpy ΔH_mix

0.000

kJ/mol; negative = exothermic mixing

Entropy Norm

0.8201

SS Former

Phase Tendency

Related Tasks

Related computation task IDs (5)

aaaddnak aaadncsf aaadsoly aaaeubki aaafcrvm

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-6583

Reference Citation

The crystal structure and related material properties of Ba2Er(CuO2)4 were obtained from the Materials Project database (MP-ID: mp-6583, 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_Ba2Er(CuO2)4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   13.86912846
_cell_length_b   13.86912846
_cell_length_c   3.87346400
_cell_angle_alpha   90.00000000
_cell_angle_beta   90.00000000
_cell_angle_gamma   163.87156278
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ba2Er(CuO2)4
_chemical_formula_sum   'Ba2 Er1 Cu4 O8'
_cell_volume   206.97447077
_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  0.63540500  0.36459500  0.50000000  1.0
  Ba  Ba1  1  0.36459500  0.63540500  0.50000000  1.0
  Er  Er2  1  0.50000000  0.50000000  0.50000000  1.0
  Cu  Cu3  1  0.06057500  0.93942500  0.00000000  1.0
  Cu  Cu4  1  0.93942500  0.06057500  0.00000000  1.0
  Cu  Cu5  1  0.21256200  0.78743800  0.00000000  1.0
  Cu  Cu6  1  0.78743800  0.21256200  0.00000000  1.0
  O  O7  1  0.71846200  0.28153800  0.00000000  1.0
  O  O8  1  0.28153800  0.71846200  0.00000000  1.0
  O  O9  1  0.55111200  0.44888800  0.00000000  1.0
  O  O10  1  0.44888800  0.55111200  0.00000000  1.0
  O  O11  1  0.05120700  0.94879300  0.50000000  1.0
  O  O12  1  0.94879300  0.05120700  0.50000000  1.0
  O  O13  1  0.14517900  0.85482100  0.00000000  1.0
  O  O14  1  0.85482100  0.14517900  0.00000000  1.0

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