Sm2CoH8Rh

High-Entropy Materials HEA

MP-ID: mp-3249127 · Space group: Amm2 (#38)

Materials Project API

Basic Information

Formula

Sm2CoH8Rh

MP-ID

mp-3249127

Elements

Sites

Density

7.0957

g/cm³

Volume

110.13

Å³

Cell a

6.2650

Cell b

6.2650

Cell c

4.8856

α Angle

90.00

β Angle

90.00

γ Angle

144.95

Space Group

Amm2

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
14.83	5.9742	3.1	(1,-1,0)
18.16	4.8856	1.7	(0,0,1)
23.52	3.7820	18.8	(1,-1,1)
24.74	3.5982	2.9	(1,0,0)
29.91	2.9871	45.4	(2,-2,0)
30.86	2.8972	100.0	(1,0,1)
32.69	2.7392	19.1	(2,-1,0)
35.22	2.5485	12.1	(2,-2,1)
36.79	2.4428	32.7	(0,0,2)
37.65	2.3893	63.8	(2,-1,1)
44.85	2.0210	1.7	(1,0,2)
48.12	1.8910	24.9	(2,-2,2)
48.24	1.8867	16.0	(1,1,0)
48.81	1.8659	15.8	(3,-2,1)
49.42	1.8441	6.5	(3,-3,1)
50.03	1.8231	12.1	(2,-1,2)
54.34	1.6883	4.3	(2,0,1)
57.80	1.5952	7.0	(1,-3,0)
57.80	1.5952	7.0	(3,-1,0)
58.77	1.5712	1.7	(1,-1,3)
59.43	1.5552	10.0	(4,-3,0)
61.11	1.5164	2.3	(1,-3,1)
61.11	1.5164	2.3	(3,-1,1)
62.15	1.4936	2.5	(4,-4,0)

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Energy Properties

Formation Energy/atom

-0.55542

eV/atom

Energy/atom

-10.92853

eV/atom

Energy above Hull

0.0000

eV/atom

Uncorrected Energy

-10.9285

eV/atom

Volume/atom

9.18

Å³

c/a Ratio

0.7798

Electronic Properties

Metallic

Metal

Band Gap

Direct Gap

CBM

N/A

Magnetic Properties

Magnetic

Yes

Total Mag. Moment

1.6147

μB

Mag. Ordering

Mag. Sites

Magnetization/Volume

0.014660

μB/Å³

Elastic Properties

Elastic data not available

Feature Analysis

Composition Overview

Element Composition (atomic fraction)

Composition Info

Major / Matrix Element

H · 0.667

Element Family

Alkali-AlkEarth

Solute Fraction

0.333

Interstitial Fraction

0.000

High-Entropy Alloy Features

Composite Radar (normalized)

Element-Class Share

Mix Entropy ΔS/R

0.9831

HEA criterion (>1.0 = high entropy)

Mix Entropy ΔS

8.1734

J/mol·K

Ω Parameter

12.1216

Ω > 1.1 favors solid solution

Atomic Size Mismatch δr

93.214%

δr < 6.6% favors single-phase solid solution

Electronegativity Diff Δχ

0.3862

smaller = more stable mixing

VEC

3.167

valence electron concentration, affects phase stability

Mix Enthalpy ΔH_mix

-0.382

kJ/mol; negative = exothermic mixing

Entropy Norm

0.7091

SS Former

Phase Tendency

Related Tasks

Related computation task IDs (1)

aaahcwkl

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-3249127

Reference Citation

The crystal structure and related material properties of Sm2CoH8Rh were obtained from the Materials Project database (MP-ID: mp-3249127, 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_Sm2CoH8Rh
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.26503713
_cell_length_b   6.26503734
_cell_length_c   4.88554880
_cell_angle_alpha   90.00000000
_cell_angle_beta   90.00000000
_cell_angle_gamma   144.94713557
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Sm2CoH8Rh
_chemical_formula_sum   'Sm2 Co1 H8 Rh1'
_cell_volume   110.13457387
_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
  Sm  Sm0  1  0.86760746  0.13239254  0.75000000  1.0
  Sm  Sm1  1  0.13600914  0.86399086  0.25000000  1.0
  Co  Co2  1  0.40049342  0.59950658  0.25000000  1.0
  H  H3  1  0.09053388  0.90946612  0.75000000  1.0
  H  H4  1  0.91279011  0.08720989  0.25000000  1.0
  H  H5  1  0.69412835  0.30587165  0.50110434  1.0
  H  H6  1  0.30781686  0.69218314  0.49823596  1.0
  H  H7  1  0.69412835  0.30587165  0.99889566  1.0
  H  H8  1  0.30781686  0.69218314  0.00176404  1.0
  H  H9  1  0.49815718  0.50184282  0.00565784  1.0
  H  H10  1  0.49815718  0.50184282  0.49434216  1.0
  Rh  Rh11  1  0.59236220  0.40763780  0.75000000  1.0

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