Rb2NaPbF6

High-Entropy Materials HEA

MP-ID: mp-989569 · Space group: Fm-3m (#225)

Materials Project API

Basic Information

Formula

Rb2NaPbF6

MP-ID

mp-989569

Elements

Sites

Density

4.4999

g/cm³

Volume

190.09

Å³

Cell a

6.4539

Cell b

6.4539

Cell c

6.4539

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 22)

2θ	d (Å)	I	hkl
16.82	5.2696	52.4	(1,1,1)
19.45	4.5636	7.9	(1,1,0)
27.64	3.2270	100.0	(2,1,1)
32.54	2.7520	32.2	(2,2,1)
34.03	2.6348	1.2	(2,2,2)
39.49	2.2818	39.8	(2,2,0)
43.21	2.0939	14.9	(3,2,2)
44.39	2.0409	4.0	(3,2,1)
48.89	1.8631	43.0	(2,-1,-1)
52.07	1.7565	12.3	(3,3,3)
57.08	1.6135	25.5	(4,2,2)
59.96	1.5428	12.2	(4,3,2)
60.90	1.5212	1.8	(4,3,3)
64.58	1.4431	19.1	(4,3,1)
67.27	1.3919	4.3	(4,4,3)
71.63	1.3174	8.3	(4,4,4)
74.20	1.2781	6.8	(5,3,3)
78.41	1.2197	22.6	(5,4,3)
80.90	1.1883	8.1	(5,4,2)
85.02	1.1409	3.9	(4,4,0)
87.48	1.1151	2.2	(3,-2,-2)
88.30	1.1068	1.0	(5,4,1)

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Energy Properties

Formation Energy/atom

-2.76022

eV/atom

Energy/atom

-4.61051

eV/atom

Energy above Hull

0.0000

eV/atom

Uncorrected Energy

-4.3333

eV/atom

Volume/atom

19.01

Å³

c/a Ratio

1.0000

Electronic Properties

Metallic

Metal

Band Gap

Direct Gap

CBM

N/A

Magnetic Properties

Magnetic

Yes

Total Mag. Moment

0.8751

μB

Mag. Ordering

Mag. Sites

Magnetization/Volume

0.004600

μB/Å³

Elastic Properties

Elastic data not available

Feature Analysis

Composition Overview

Element Composition (atomic fraction)

Composition Info

Major / Matrix Element

F · 0.600

Element Family

Metalloid-Nonmetal

Solute Fraction

0.400

Interstitial Fraction

0.000

High-Entropy Alloy Features

Composite Radar (normalized)

Element-Class Share

Mix Entropy ΔS/R

1.0889

HEA criterion (>1.0 = high entropy)

Mix Entropy ΔS

9.0531

J/mol·K

Ω Parameter

1.0844

Ω > 1.1 favors solid solution

Atomic Size Mismatch δr

70.042%

δr < 6.6% favors single-phase solid solution

Electronegativity Diff Δχ

1.4090

smaller = more stable mixing

VEC

3.700

valence electron concentration, affects phase stability

Mix Enthalpy ΔH_mix

-1.601

kJ/mol; negative = exothermic mixing

Entropy Norm

0.7855

SS Former

Phase Tendency

Related Tasks

Related computation task IDs (5)

aaadmhlz aaaduozr aaaealro aaaepkxn aaafaznl

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-989569

Reference Citation

The crystal structure and related material properties of Rb2NaPbF6 were obtained from the Materials Project database (MP-ID: mp-989569, 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_Rb2NaPbF6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.45389653
_cell_length_b   6.45389653
_cell_length_c   6.45389653
_cell_angle_alpha   60.00000000
_cell_angle_beta   60.00000000
_cell_angle_gamma   60.00000000
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Rb2NaPbF6
_chemical_formula_sum   'Rb2 Na1 Pb1 F6'
_cell_volume   190.08637869
_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  0.25000000  0.25000000  0.25000000  1.0
  Rb  Rb1  1  0.75000000  0.75000000  0.75000000  1.0
  Na  Na2  1  0.50000000  0.50000000  0.50000000  1.0
  Pb  Pb3  1  0.00000000  0.00000000  0.00000000  1.0
  F  F4  1  0.24767900  0.75232100  0.75232100  1.0
  F  F5  1  0.24767900  0.75232100  0.24767900  1.0
  F  F6  1  0.75232100  0.24767900  0.75232100  1.0
  F  F7  1  0.75232100  0.75232100  0.24767900  1.0
  F  F8  1  0.24767900  0.24767900  0.75232100  1.0
  F  F9  1  0.75232100  0.24767900  0.24767900  1.0

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