Rb(BeAs)2

High-Entropy Materials HEA Traditional Materials TRA

MP-ID: mp-3201720 · Space group: I4/mmm (#139)

Materials Project API

Basic Information

Formula

Rb(BeAs)2

MP-ID

mp-3201720

Elements

Sites

Density

4.1362

g/cm³

Volume

101.71

Å³

Cell a

8.1149

Cell b

8.1149

Cell c

8.1149

α Angle

154.12

β Angle

154.12

γ Angle

36.93

Space Group

I4/mmm

Point Group

4/mmm

Crystal System

Tetragonal

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
30.13	2.9662	100.0	(2,1,-1)
34.91	2.5704	30.9	(1,-1,0)
34.97	2.5657	14.1	(3,3,-3)
36.87	2.4380	1.1	(1,1,0)
38.31	2.3494	1.2	(3,2,-2)
38.31	2.3494	1.2	(3,2,-3)
47.24	1.9243	1.0	(4,4,-4)
50.20	1.8175	13.1	(1,-1,1)
50.24	1.8159	6.0	(3,3,-2)
50.24	1.8159	12.1	(4,2,-3)
50.24	1.8159	6.0	(3,3,-4)
59.66	1.5497	6.9	(2,1,0)
59.66	1.5497	13.8	(3,0,-1)
59.66	1.5497	6.9	(2,1,-3)
59.75	1.5477	5.8	(5,4,-4)
59.75	1.5477	5.8	(5,4,-5)
62.64	1.4831	2.5	(4,2,-2)
62.64	1.4831	2.5	(2,4,-2)
62.64	1.4831	5.1	(4,2,-4)
73.72	1.2852	4.2	(2,-2,0)
73.88	1.2829	1.5	(6,6,-6)
81.65	1.1793	2.8	(3,0,0)
81.65	1.1793	2.8	(3,0,-3)
81.72	1.1784	2.4	(5,4,-3)

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Energy Properties

Formation Energy/atom

-0.40917

eV/atom

Energy/atom

-10.81354

eV/atom

Energy above Hull

0.0000

eV/atom

Uncorrected Energy

-10.8135

eV/atom

Volume/atom

20.34

Å³

c/a Ratio

1.0000

Electronic Properties

Metallic

Metal

Band Gap

Direct Gap

CBM

N/A

Magnetic Properties

Magnetic

Total Mag. Moment

0.0000

μB

Mag. Ordering

Mag. Sites

Magnetization/Volume

0.000000

μB/Å³

Elastic Properties

Elastic data not available

Feature Analysis

Composition Overview

Element Composition (atomic fraction)

Composition Info

Major / Matrix Element

Be · 0.400

Element Family

Alkali-AlkEarth

Solute Fraction

0.600

Interstitial Fraction

0.000

High-Entropy Alloy Features

Composite Radar (normalized)

Element-Class Share

Mix Entropy ΔS/R

1.0549

HEA criterion (>1.0 = high entropy)

Mix Entropy ΔS

8.7706

J/mol·K

Ω Parameter

0.0000

Ω > 1.1 favors solid solution

Atomic Size Mismatch δr

35.282%

δr < 6.6% favors single-phase solid solution

Electronegativity Diff Δχ

0.5025

smaller = more stable mixing

VEC

2.200

valence electron concentration, affects phase stability

Mix Enthalpy ΔH_mix

0.000

kJ/mol; negative = exothermic mixing

Entropy Norm

0.9602

SS Former

Phase Tendency

Traditional Material Features

ROM Blended-Feature Radar

Rating & Classification

Tier

Score

0.388

Family

Be-rich Multi-Component

Matrix Element

Be · 0.400

Related Tasks

Related computation task IDs (1)

aaahaehc

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-3201720

Reference Citation

The crystal structure and related material properties of Rb(BeAs)2 were obtained from the Materials Project database (MP-ID: mp-3201720, 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_Rb(BeAs)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.11491562
_cell_length_b   8.11491542
_cell_length_c   8.11491468
_cell_angle_alpha   154.11503780
_cell_angle_beta   154.11503798
_cell_angle_gamma   36.93241911
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Rb(BeAs)2
_chemical_formula_sum   'Rb1 Be2 As2'
_cell_volume   101.70554238
_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  0.00000000  0.00000000  0.00000000  1.0
  Be  Be1  1  0.75000000  0.25000000  0.50000000  1.0
  Be  Be2  1  0.25000000  0.75000000  0.50000000  1.0
  As  As3  1  0.34284926  0.34284926  0.00000000  1.0
  As  As4  1  0.65715074  0.65715074  1.00000000  1.0

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