Er9TmOs4

High-Entropy Materials HEA Traditional Materials TRA

MP-ID: mp-3295137 · Space group: C2 (#5)

Materials Project API

Basic Information

Formula

Er9TmOs4

MP-ID

mp-3295137

Elements

Sites

Density

11.6177

g/cm³

Volume

348.06

Å³

Cell a

6.2704

Cell b

7.2925

Cell c

8.2942

α Angle

97.01

β Angle

112.21

γ Angle

90.00

Space Group

Point Group

Crystal System

Monoclinic

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
11.63	7.6119	10.4	(0,0,1)
15.28	5.7979	9.0	(1,0,0)
19.14	4.6379	2.8	(1,-1,0)
20.11	4.4160	98.8	(1,-1,-1)
23.37	3.8059	12.8	(0,0,2)
24.58	3.6222	14.5	(1,-1,1)
25.86	3.4458	2.0	(0,2,-1)
26.83	3.3225	2.1	(1,1,1)
28.44	3.1388	51.1	(1,-2,0)
28.70	3.1101	9.5	(0,2,1)
29.78	3.0004	18.0	(1,-2,-1)
30.84	2.8989	7.1	(2,0,0)
31.09	2.8763	95.7	(2,1,-1)
31.82	2.8125	54.4	(0,2,-2)
31.82	2.8123	34.7	(1,-2,1)
31.82	2.8123	34.7	(1,2,-2)
32.70	2.7389	57.7	(1,0,2)
32.70	2.7389	57.7	(1,0,-3)
32.70	2.7385	63.1	(2,-1,0)
33.59	2.6682	21.6	(1,-1,2)
33.59	2.6682	21.6	(1,1,-3)
33.89	2.6452	76.6	(2,1,0)
35.36	2.5385	75.1	(1,-2,-2)
35.38	2.5373	31.7	(0,0,3)

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Energy Properties

Formation Energy/atom

-0.36892

eV/atom

Energy/atom

-39.82541

eV/atom

Energy above Hull

0.0000

eV/atom

Uncorrected Energy

-39.8254

eV/atom

Volume/atom

24.86

Å³

c/a Ratio

1.3228

Electronic Properties

Metallic

Metal

Band Gap

Direct Gap

CBM

N/A

Magnetic Properties

Magnetic

Total Mag. Moment

0.0315

μB

Mag. Ordering

Mag. Sites

Magnetization/Volume

0.000090

μB/Å³

Elastic Properties

Elastic data not available

Feature Analysis

Composition Overview

Element Composition (atomic fraction)

Composition Info

Major / Matrix Element

Er · 0.643

Element Family

Lanthanide

Solute Fraction

0.357

Interstitial Fraction

0.000

High-Entropy Alloy Features

Composite Radar (normalized)

Element-Class Share

Mix Entropy ΔS/R

0.8305

HEA criterion (>1.0 = high entropy)

Mix Entropy ΔS

6.9045

J/mol·K

Ω Parameter

0.0000

Ω > 1.1 favors solid solution

Atomic Size Mismatch δr

11.047%

δr < 6.6% favors single-phase solid solution

Electronegativity Diff Δχ

0.4332

smaller = more stable mixing

VEC

10.929

valence electron concentration, affects phase stability

Mix Enthalpy ΔH_mix

0.000

kJ/mol; negative = exothermic mixing

Entropy Norm

0.7559

SS Former

Phase Tendency

Traditional Material Features

ROM Blended-Feature Radar

Rating & Classification

Tier

Score

0.613

Family

Er-rich Multi-Component

Matrix Element

Er · 0.643

Related Tasks

Related computation task IDs (1)

aaahfmmb

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-3295137

Reference Citation

The crystal structure and related material properties of Er9TmOs4 were obtained from the Materials Project database (MP-ID: mp-3295137, 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_Er9TmOs4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.27038368
_cell_length_b   7.29246281
_cell_length_c   8.29423778
_cell_angle_alpha   97.00908375
_cell_angle_beta   112.20962146
_cell_angle_gamma   90.00000706
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Er9TmOs4
_chemical_formula_sum   'Er9 Tm1 Os4'
_cell_volume   348.06450437
_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  0.79361969  0.08425755  0.81802269  1.0
  Er  Er1  1  0.97559700  0.41574245  0.18197731  1.0
  Er  Er2  1  0.20607367  0.91523295  0.18211435  1.0
  Er  Er3  1  0.02395931  0.58476705  0.81788565  1.0
  Er  Er4  1  0.20627177  0.18088010  0.56557788  1.0
  Er  Er5  1  0.64069489  0.31911990  0.43442212  1.0
  Er  Er6  1  0.79403509  0.81907310  0.43412600  1.0
  Er  Er7  1  0.35990909  0.68092690  0.56587400  1.0
  Er  Er8  1  0.42044692  0.25000000  1.00000000  1.0
  Tm  Tm9  1  0.57867961  0.75000000  0.00000000  1.0
  Os  Os10  1  0.60436108  0.42091835  0.78030411  1.0
  Os  Os11  1  0.82405598  0.07908165  0.21969589  1.0
  Os  Os12  1  0.39617029  0.57955947  0.22004566  1.0
  Os  Os13  1  0.17612563  0.92044053  0.77995434  1.0

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