Sm3Th2Pb3Br

High-Entropy Materials HEA

MP-ID: mp-3294203 · Space group: P6_3/mcm (#193)

Materials Project API

Basic Information

Formula

Sm3Th2Pb3Br

MP-ID

mp-3294203

Elements

Sites

Density

10.1485

g/cm³

Volume

529.05

Å³

Cell a

9.5403

Cell b

9.5403

Cell c

6.7119

α Angle

90.00

β Angle

90.00

γ Angle

120.00

Space Group

P6_3/mcm

Point Group

6/mmm

Crystal System

Hexagonal

Bravais Lattice

Stability

Yes

Packing Fraction

0.7405

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
10.71	8.2621	9.7	(1,0,-1,0)
22.87	3.8882	4.7	(2,-1,-1,1)
26.56	3.3559	8.1	(0,0,0,2)
28.58	3.1228	1.6	(1,-3,2,0)
28.58	3.1228	7.8	(3,-1,-2,0)
28.71	3.1092	3.3	(1,0,-1,2)
31.60	2.8313	50.2	(3,-1,-2,1)
32.51	2.7540	52.4	(3,-3,0,0)
32.51	2.7540	26.2	(3,0,-3,0)
32.62	2.7447	100.0	(2,-1,-1,2)
34.43	2.6048	5.3	(2,0,-2,2)
37.72	2.3851	1.5	(4,-2,-2,0)
39.32	2.2915	2.2	(4,-1,-3,0)
40.12	2.2474	1.8	(2,2,-4,1)
41.65	2.1686	17.2	(4,-1,-3,1)
42.46	2.1289	1.7	(3,0,-3,2)
46.72	1.9441	27.2	(4,-2,-2,2)
50.00	1.8241	4.0	(3,-5,2,1)
50.00	1.8241	4.0	(5,-2,-3,1)
50.16	1.8187	14.0	(3,-1,-2,3)
50.63	1.8029	2.0	(4,-5,1,0)
50.63	1.8029	2.0	(5,-1,-4,0)
51.99	1.7591	2.3	(4,-4,0,2)
51.99	1.7591	1.1	(4,0,-4,2)

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Energy Properties

Formation Energy/atom

-0.89441

eV/atom

Energy/atom

-47.36814

eV/atom

Energy above Hull

0.0000

eV/atom

Uncorrected Energy

-47.3681

eV/atom

Volume/atom

29.39

Å³

c/a Ratio

0.7035

Electronic Properties

Metallic

Metal

Band Gap

Direct Gap

CBM

N/A

Magnetic Properties

Magnetic

Total Mag. Moment

0.0779

μB

Mag. Ordering

Mag. Sites

Magnetization/Volume

0.000150

μB/Å³

Elastic Properties

Elastic data not available

Feature Analysis

Composition Overview

Element Composition (atomic fraction)

Composition Info

Major / Matrix Element

Sm · 0.333

Element Family

Lanthanide

Solute Fraction

0.667

Interstitial Fraction

0.000

High-Entropy Alloy Features

Composite Radar (normalized)

Element-Class Share

Mix Entropy ΔS/R

1.3108

HEA criterion (>1.0 = high entropy)

Mix Entropy ΔS

10.8979

J/mol·K

Ω Parameter

0.0000

Ω > 1.1 favors solid solution

Atomic Size Mismatch δr

12.057%

δr < 6.6% favors single-phase solid solution

Electronegativity Diff Δχ

0.6563

smaller = more stable mixing

VEC

4.333

valence electron concentration, affects phase stability

Mix Enthalpy ΔH_mix

0.000

kJ/mol; negative = exothermic mixing

Entropy Norm

0.9455

SS Former

Phase Tendency

Related Tasks

Related computation task IDs (1)

aaahflcd

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-3294203

Reference Citation

The crystal structure and related material properties of Sm3Th2Pb3Br were obtained from the Materials Project database (MP-ID: mp-3294203, 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_Sm3Th2Pb3Br
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.54028267
_cell_length_b   9.54028400
_cell_length_c   6.71185676
_cell_angle_alpha   90.00000000
_cell_angle_beta   90.00000000
_cell_angle_gamma   120.00000231
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Sm3Th2Pb3Br
_chemical_formula_sum   'Sm6 Th4 Pb6 Br2'
_cell_volume   529.04893795
_cell_formula_units_Z   2
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  0.72924791  1.00000000  0.75000000  1.0
  Sm  Sm1  1  1.00000000  0.27075209  0.25000000  1.0
  Sm  Sm2  1  0.72924791  0.72924791  0.25000000  1.0
  Sm  Sm3  1  0.27075209  0.00000000  0.25000000  1.0
  Sm  Sm4  1  0.27075209  0.27075209  0.75000000  1.0
  Sm  Sm5  1  0.00000000  0.72924791  0.75000000  1.0
  Th  Th6  1  0.33333300  0.66666700  0.50000000  1.0
  Th  Th7  1  0.33333300  0.66666700  0.00000000  1.0
  Th  Th8  1  0.66666700  0.33333300  0.50000000  1.0
  Th  Th9  1  0.66666700  0.33333300  0.00000000  1.0
  Pb  Pb10  1  0.38261417  1.00000000  0.75000000  1.0
  Pb  Pb11  1  0.61738583  0.00000000  0.25000000  1.0
  Pb  Pb12  1  1.00000000  0.61738583  0.25000000  1.0
  Pb  Pb13  1  0.61738583  0.61738583  0.75000000  1.0
  Pb  Pb14  1  0.00000000  0.38261417  0.75000000  1.0
  Pb  Pb15  1  0.38261417  0.38261417  0.25000000  1.0
  Br  Br16  1  0.00000000  0.00000000  0.50000000  1.0
  Br  Br17  1  0.00000000  0.00000000  0.00000000  1.0

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