ErTm(CoOs)2

High-Entropy Materials HEA

MP-ID: mp-3248711 · Space group: Imm2 (#44)

Materials Project API

Basic Information

Formula

ErTm(CoOs)2

MP-ID

mp-3248711

Elements

Sites

Density

14.0360

g/cm³

Volume

98.73

Å³

Cell a

5.2292

Cell b

5.2292

Cell c

5.2292

α Angle

122.04

β Angle

120.93

γ Angle

87.46

Space Group

Imm2

Point Group

mm2

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
20.86	4.2591	21.8	(1,0,0)
21.11	4.2089	13.8	(0,1,0)
23.54	3.7788	20.5	(1,1,-1)
34.33	2.6118	17.1	(1,1,0)
34.33	2.6118	51.2	(2,0,-1)
34.80	2.5779	50.2	(1,-1,1)
35.43	2.5338	1.0	(1,-1,-1)
39.83	2.2634	81.1	(2,1,-1)
39.97	2.2558	11.7	(1,2,-1)
39.97	2.2558	11.7	(2,1,-2)
41.06	2.1984	37.9	(2,-1,0)
41.06	2.1984	12.6	(0,1,-2)
41.47	2.1776	100.0	(1,-2,0)
41.47	2.1776	33.3	(1,0,-2)
42.45	2.1296	39.2	(2,0,0)
42.98	2.1045	22.0	(0,2,0)
42.98	2.1045	22.0	(2,0,-2)
48.16	1.8894	1.6	(2,2,-2)
50.51	1.8071	2.7	(2,-2,0)
54.02	1.6976	1.2	(2,1,0)
54.35	1.6880	1.2	(1,2,0)
54.78	1.6758	1.7	(2,-1,1)
56.44	1.6302	8.5	(1,1,1)
56.44	1.6302	2.8	(1,1,-3)

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Energy Properties

Formation Energy/atom

-0.34353

eV/atom

Energy/atom

-33.92443

eV/atom

Energy above Hull

0.0000

eV/atom

Uncorrected Energy

-33.9244

eV/atom

Volume/atom

16.45

Å³

c/a Ratio

1.0000

Electronic Properties

Metallic

Metal

Band Gap

Direct Gap

CBM

N/A

Magnetic Properties

Magnetic

Yes

Total Mag. Moment

2.9927

μB

Mag. Ordering

FiM

Mag. Sites

Magnetization/Volume

0.030310

μB/Å³

Elastic Properties

Elastic data not available

Feature Analysis

Composition Overview

Element Composition (atomic fraction)

Composition Info

Major / Matrix Element

Co · 0.333

Element Family

3d-TM

Solute Fraction

0.667

Interstitial Fraction

0.000

High-Entropy Alloy Features

Composite Radar (normalized)

Element-Class Share

Mix Entropy ΔS/R

1.3297

HEA criterion (>1.0 = high entropy)

Mix Entropy ΔS

11.0548

J/mol·K

Ω Parameter

4.5067

Ω > 1.1 favors solid solution

Atomic Size Mismatch δr

14.898%

δr < 6.6% favors single-phase solid solution

Electronegativity Diff Δχ

0.3969

smaller = more stable mixing

VEC

9.833

valence electron concentration, affects phase stability

Mix Enthalpy ΔH_mix

-5.629

kJ/mol; negative = exothermic mixing

Entropy Norm

0.9591

SS Former

Phase Tendency

Related Tasks

Related computation task IDs (1)

aaahcvul

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-3248711

Reference Citation

The crystal structure and related material properties of ErTm(CoOs)2 were obtained from the Materials Project database (MP-ID: mp-3248711, 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_ErTm(CoOs)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.22920407
_cell_length_b   5.22920434
_cell_length_c   5.22920333
_cell_angle_alpha   122.03549679
_cell_angle_beta   120.92564004
_cell_angle_gamma   87.45696095
_symmetry_Int_Tables_number   1
_chemical_formula_structural   ErTm(CoOs)2
_chemical_formula_sum   'Er1 Tm1 Co2 Os2'
_cell_volume   98.72880663
_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
  Er  Er0  1  0.87062083  0.12062083  0.75000000  1.0
  Tm  Tm1  1  0.12965093  0.87965093  0.25000000  1.0
  Co  Co2  1  0.00006895  0.49991190  0.50015705  1.0
  Co  Co3  1  0.49975485  0.49991190  0.99984295  1.0
  Os  Os4  1  0.49995172  0.99993458  0.99998286  1.0
  Os  Os5  1  0.49995172  0.49996886  0.50001714  1.0

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