Rb8Tb6GaBr20

High-Entropy Materials HEA

MP-ID: mp-3292842 · Space group: Fm-3m (#225)

Materials Project API

Basic Information

Formula

Rb8Tb6GaBr20

MP-ID

mp-3292842

Elements

Sites

Density

4.3013

g/cm³

Volume

1,275.94

Å³

Cell a

12.1744

Cell b

12.1744

Cell c

12.1744

α Angle

60.00

β Angle

60.00

γ Angle

60.00

Space Group

Fm-3m

Point Group

m-3m

Crystal System

Cubic

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
8.90	9.9404	31.0	(1,0,0)
8.90	9.9404	31.0	(0,1,0)
10.28	8.6086	50.2	(1,1,0)
17.08	5.1912	2.6	(2,2,1)
17.85	4.9702	24.8	(2,0,0)
20.64	4.3043	5.1	(2,2,0)
22.51	3.9499	34.0	(3,1,1)
23.10	3.8499	1.6	(3,2,1)
23.10	3.8499	4.8	(3,1,2)
25.34	3.5145	7.3	(3,1,0)
26.91	3.3135	73.0	(3,2,0)
29.34	3.0436	12.5	(4,2,2)
30.72	2.9103	15.4	(4,2,1)
31.17	2.8695	65.8	(4,1,1)
31.17	2.8695	90.0	(0,3,-1)
32.90	2.7223	42.6	(4,3,1)
34.56	2.5956	5.2	(4,2,0)
36.14	2.4851	10.1	(4,0,0)
37.30	2.4109	12.6	(4,3,0)
37.67	2.3876	2.6	(5,2,3)
40.23	2.2415	9.3	(5,3,1)
41.98	2.1522	14.6	(4,4,0)
43.00	2.1034	8.9	(5,2,0)
43.34	2.0879	4.4	(5,4,1)

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Energy Properties

Formation Energy/atom

-1.98687

eV/atom

Energy/atom

-18.42761

eV/atom

Energy above Hull

0.0000

eV/atom

Uncorrected Energy

-18.4276

eV/atom

Volume/atom

36.46

Å³

c/a Ratio

1.0000

Electronic Properties

Metallic

Metal

Band Gap

Direct Gap

CBM

N/A

Magnetic Properties

Magnetic

Yes

Total Mag. Moment

1.0003

μB

Mag. Ordering

Mag. Sites

Magnetization/Volume

0.000780

μB/Å³

Elastic Properties

Elastic data not available

Feature Analysis

Composition Overview

Element Composition (atomic fraction)

Composition Info

Major / Matrix Element

Br · 0.571

Element Family

Metalloid-Nonmetal

Solute Fraction

0.429

Interstitial Fraction

0.000

High-Entropy Alloy Features

Composite Radar (normalized)

Element-Class Share

Mix Entropy ΔS/R

1.0610

HEA criterion (>1.0 = high entropy)

Mix Entropy ΔS

8.8215

J/mol·K

Ω Parameter

0.0000

Ω > 1.1 favors solid solution

Atomic Size Mismatch δr

32.319%

δr < 6.6% favors single-phase solid solution

Electronegativity Diff Δχ

0.9852

smaller = more stable mixing

VEC

4.714

valence electron concentration, affects phase stability

Mix Enthalpy ΔH_mix

0.000

kJ/mol; negative = exothermic mixing

Entropy Norm

0.7654

SS Former

Phase Tendency

Related Tasks

Related computation task IDs (1)

aaahfjbu

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-3292842

Reference Citation

The crystal structure and related material properties of Rb8Tb6GaBr20 were obtained from the Materials Project database (MP-ID: mp-3292842, 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_Rb8Tb6GaBr20
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   12.17443732
_cell_length_b   12.17443671
_cell_length_c   12.17443606
_cell_angle_alpha   59.99999919
_cell_angle_beta   60.00000084
_cell_angle_gamma   59.99999743
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Rb8Tb6GaBr20
_chemical_formula_sum   'Rb8 Tb6 Ga1 Br20'
_cell_volume   1275.94402065
_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
  Rb  Rb0  1  0.35872812  0.35872812  0.35872812  1.0
  Rb  Rb1  1  0.64127188  0.64127188  0.64127188  1.0
  Rb  Rb2  1  0.35872812  0.35872812  0.92381463  1.0
  Rb  Rb3  1  0.35872812  0.92381463  0.35872812  1.0
  Rb  Rb4  1  0.64127188  0.64127188  0.07618537  1.0
  Rb  Rb5  1  0.64127188  0.07618537  0.64127188  1.0
  Rb  Rb6  1  0.92381463  0.35872812  0.35872812  1.0
  Rb  Rb7  1  0.07618537  0.64127188  0.64127188  1.0
  Tb  Tb8  1  0.83789398  0.16210602  0.16210602  1.0
  Tb  Tb9  1  0.16210602  0.83789398  0.83789398  1.0
  Tb  Tb10  1  0.16210602  0.83789398  0.16210602  1.0
  Tb  Tb11  1  0.83789398  0.16210602  0.83789398  1.0
  Tb  Tb12  1  0.16210602  0.16210602  0.83789398  1.0
  Tb  Tb13  1  0.83789398  0.83789398  0.16210602  1.0
  Ga  Ga14  1  0.00000000  0.00000000  0.00000000  1.0
  Br  Br15  1  0.33616670  0.00000000  1.00000000  1.0
  Br  Br16  1  0.66383330  1.00000000  0.00000000  1.0
  Br  Br17  1  0.00000000  0.33616670  0.66383330  1.0
  Br  Br18  1  1.00000000  0.66383330  0.33616670  1.0
  Br  Br19  1  0.00000000  0.33616670  1.00000000  1.0
  Br  Br20  1  0.66383330  1.00000000  0.33616670  1.0
  Br  Br21  1  1.00000000  0.66383330  0.00000000  1.0
  Br  Br22  1  0.33616670  0.00000000  0.66383330  1.0
  Br  Br23  1  0.00000000  0.00000000  0.33616670  1.0
  Br  Br24  1  1.00000000  1.00000000  0.66383330  1.0
  Br  Br25  1  0.66383330  0.33616670  0.00000000  1.0
  Br  Br26  1  0.33616670  0.66383330  1.00000000  1.0
  Br  Br27  1  0.67226016  0.32773984  0.32773984  1.0
  Br  Br28  1  0.32773984  0.67226016  0.67226016  1.0
  Br  Br29  1  0.32773984  0.67226016  0.32773984  1.0
  Br  Br30  1  0.67226016  0.32773984  0.67226016  1.0
  Br  Br31  1  0.32773984  0.32773984  0.67226016  1.0
  Br  Br32  1  0.67226016  0.67226016  0.32773984  1.0
  Br  Br33  1  0.25000000  0.25000000  0.25000000  1.0
  Br  Br34  1  0.75000000  0.75000000  0.75000000  1.0

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