Ba2CoAg2(SeO)2

High-Entropy Materials HEA

MP-ID: mp-1078198 · Space group: I4/mmm (#139)

Materials Project API

Basic Information

Formula

Ba2CoAg2(SeO)2

MP-ID

mp-1078198

Elements

Sites

Density

6.6361

g/cm³

Volume

184.98

Å³

Cell a

11.0273

Cell b

11.0273

Cell c

11.0273

α Angle

158.19

β Angle

158.19

γ Angle

31.04

Space Group

I4/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
8.32	10.6252	21.0	(1,1,-1)
16.69	5.3126	4.5	(2,2,-2)
21.71	4.0943	9.6	(1,0,0)
24.76	3.5951	6.5	(2,1,-1)
25.14	3.5418	14.6	(3,3,-3)
30.01	2.9775	100.0	(3,2,-2)
30.29	2.9504	17.8	(0,0,1)
31.47	2.8428	56.5	(1,1,0)
33.74	2.6563	4.8	(4,4,-4)
34.78	2.5793	96.1	(2,2,-1)
36.61	2.4548	53.8	(4,3,-3)
39.76	2.2669	7.9	(3,3,-2)
43.37	2.0862	71.0	(1,-1,1)
44.07	2.0550	6.6	(5,4,-4)
44.24	2.0472	1.9	(2,0,0)
45.97	1.9741	22.9	(4,4,-3)
49.01	1.8588	2.3	(1,0,1)
50.58	1.8044	1.8	(2,1,0)
50.79	1.7976	8.9	(4,2,-2)
51.61	1.7709	19.7	(6,6,-6)
52.18	1.7531	3.4	(6,5,-5)
53.11	1.7243	16.4	(5,5,-4)
53.64	1.7086	37.8	(3,2,-1)
56.05	1.6407	3.8	(5,3,-3)

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Energy Properties

Formation Energy/atom

-1.32759

eV/atom

Energy/atom

-5.05481

eV/atom

Energy above Hull

0.2302

eV/atom

Uncorrected Energy

-4.7202

eV/atom

Volume/atom

20.55

Å³

c/a Ratio

1.0000

Electronic Properties

Metallic

Metal

Band Gap

Direct Gap

CBM

N/A

Magnetic Properties

Magnetic

Yes

Total Mag. Moment

2.9994

μB

Mag. Ordering

Mag. Sites

Magnetization/Volume

0.016210

μB/Å³

Elastic Properties

Elastic data not available

Feature Analysis

Composition Overview

Element Composition (atomic fraction)

Composition Info

Major / Matrix Element

Ba · 0.222

Element Family

Alkali-AlkEarth

Solute Fraction

0.778

Interstitial Fraction

0.000

High-Entropy Alloy Features

Composite Radar (normalized)

Element-Class Share

Mix Entropy ΔS/R

1.5811

HEA criterion (>1.0 = high entropy)

Mix Entropy ΔS

13.1452

J/mol·K

Ω Parameter

43.1595

Ω > 1.1 favors solid solution

Atomic Size Mismatch δr

39.807%

δr < 6.6% favors single-phase solid solution

Electronegativity Diff Δχ

0.8813

smaller = more stable mixing

VEC

5.667

valence electron concentration, affects phase stability

Mix Enthalpy ΔH_mix

0.248

kJ/mol; negative = exothermic mixing

Entropy Norm

0.9824

SS Former

Phase Tendency

Related Tasks

Related computation task IDs (5)

aaadndun aaadsyyj aaaeajqg aaaeuape aaafxdij

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-1078198

Reference Citation

The crystal structure and related material properties of Ba2CoAg2(SeO)2 were obtained from the Materials Project database (MP-ID: mp-1078198, 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

Loading 3D structure…

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Raw CIF Data

# generated using pymatgen
data_Ba2CoAg2(SeO)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   11.02726047
_cell_length_b   11.02726047
_cell_length_c   11.02726047
_cell_angle_alpha   158.18907553
_cell_angle_beta   158.18907553
_cell_angle_gamma   31.03750237
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ba2CoAg2(SeO)2
_chemical_formula_sum   'Ba2 Co1 Ag2 Se2 O2'
_cell_volume   184.98051574
_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  0.58799700  0.58799700  0.00000000  1.0
  Ba  Ba1  1  0.41200300  0.41200300  0.00000000  1.0
  Co  Co2  1  0.00000000  0.00000000  0.00000000  1.0
  Ag  Ag3  1  0.75000000  0.25000000  0.50000000  1.0
  Ag  Ag4  1  0.25000000  0.75000000  0.50000000  1.0
  Se  Se5  1  0.83663800  0.83663800  0.00000000  1.0
  Se  Se6  1  0.16336200  0.16336200  0.00000000  1.0
  O  O7  1  0.00000000  0.50000000  0.50000000  1.0
  O  O8  1  0.50000000  0.00000000  0.50000000  1.0

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